Absolute Rating

Is used to accurately define the grade or level of filtration delivered. This absolute rating means 100% of particles larger than the filter rating (usually in microns) will be removed or entrapped on or within the filter medium i.e. 1 micron absolute will remove or entrap all particles greater than 1 micron as opposed to 1 micron nominal which may still let particles greater than 1 micron through. Back to Top

Activated Carbon

A filter material made from coal or coconut shell carbon and used for removing taste and smell from water and air. Black in colour and comes in powder, granulated or extruded block form. Back to Top


Refers to a treatment process or activity that requires or depends on air or oxygen. Back to Top


Are simple tiny plants or seaweed that grow and multiply if nutrients are present and chlorine or sanitiser levels are low. Most algae are invisible except in millions. In sunlight they convert carbon dioxide into oxygen by photosynthesis. They are larger than bacteria and viruses but generally smaller than 5 microns. Back to Top


Is the sum of all alkaline chemicals in the water. A measurement of all carbonates, biocarbonates, hydroxides and other alkaline substances. It is closely related to pH and known as the buffering capacity of the water. Back to Top


(Aluminium Sulphate) – is a flocculant product used in water treatment to coagulate (bind together) colloidal very fine dirt particles and other organic materials so they fall to the bottom of a tank where they can be removed. This process then leaves the water clear. Alum is also used to remove phosphorus from water. Back to Top


Is a metallic element mined from Bauxite found in the ground. Aluminium salts have and are used as coagulants in water treatment. Aluminium in drinking water should not exceed 0.2 mg/L and preferably under 0.1 mg/L. It is being phased out of use in drinking water treatment plants due to links with Alzheimer’s disease. It is also used in many other products such as antacids, anti-perspirants, food additives, vaccines, food packaging and utensils. Back to Top

Ambient Temperature

The current or average air temperature in the room/location or environment. Back to Top


A colourless gas with a sharp offensive odour. It is made by humans and nature and dissolves easily in water. It is made up of 1 nitrogen and 3 hydrogen atoms and is very alkaline in water based solutions. It is found in many household cleaners and chloramines. It is irritating to the skin, eyes, nose, throat and lungs. Levels in drinking water should not exceed 0.5 mg/L. Back to Top


Description of any process, activity or treatment that needs no air or oxygen. Refers to a treatment process or activity that requires no air or oxygen. Back to Top


Is an electrode, rod or pole through which a low voltage electric current flows. This low voltage causes a process called electrolysis whereby salts in the water collect on the electrode or the electrode erodes by oxidation. Back to Top


A form or type of activated carbon. Back to Top


A naturally occurring element that forms a number of poisonous compounds. Organic arsenic is less harmful than inorganic. Inorganic arsenic compounds are mainly used to preserve wood, insecticides, pesticides and weed killers. Pentavalent arsenic is generally the most common form found in surface waters while the trivalent form is found mainly in ground waters and deep lake sediments. The concentration of arsenic in drinking water should not exceed 0.007 mg/L. Back to Top


Are used with UV lamps. They are an electronic device that regulate the flow of current through the lamp. Back to Top

Ball valve

Is a type of isolating valve containing a circular ball with a hold through it. It is turned 90° or ¼ turn to open or close. Back to Top

Blastocystis Hominis

Is a single celled parasite that infects the gastrointestinal tracts of humans, animals, birds rodents, reptiles, amphibians, fish and cockroaches. The most frequent symptoms are abdominal pain, constipation and diarrhea. It was originally thought to be protozoan but is now classified as a stramenopiles. Other stramenopiles include brown algae, mildew and diatoms. They all have 4 various life cycle stages including cyst forms. The blastocystis cyst form can infect humans with 9 species able to do this. The blastocystis cyst form is the way the infection is transmitted. It is also very resistant to chemicals in this form and is able to survive in harsh conditions because of its multi-layered cyst wall. Blastocystis can remain in the intestines for weeks, months or years with many people having no symptoms at all. This parasite is very common in developing countries although it is also prevalent in many parts of Australia. The cyst form varies enormously in size between 1 and 200 microns with an average size of 6-40 microns. Standard high quality 1 micron filtration should remove this parasite from the water although sub-micron absolute filtration would be recommended as a better preventative measure. Back to Top


A non-metallic element found in the ground and many food products. It is used in glass manufacture, cleaners, antiseptics, flame retardants, fertilizers, algaecides, insecticides and herbicides. The concentration of boron in drinking water can be reduced by activated carbon or lime softening. High doses of boron are poisonous to humans leading to gastro-intestinal problems, skin eruptions, etc. Based on health considerations, the concentration of boron in drinking water should not exceed 0.3 mg/L. Back to Top

Butterfly valve

Is a type of isolating valve containing a circular disc inside a pipe. It is normally used in large diameter pipes and geared to make it easier to open and close. Back to Top


Crystalline calcium carbonate found in marble and other limestone Back to Top

Check valve

Or non return valve allows flow in a pipe line in only one direction. Back to Top


Chloramine is now becoming a common disinfectant for drinking water supplies replacing Chlorine in many capital cities including Sydney, Melbourne and Brisbane. This rollout will continue in the future with more and more towns and cities moving to this form of disinfectant. The main reason for this is the considerably reduced level of carcinogenic by-product trihalomethanes (THM’s) formed when using chloramines and it stays in the water much longer, a much higher residual. The most common form is Monochloramine with concentrations ranging from 1.5 to 2.5 mg/L. Typical residual in Australia is 0.5 mg/L with a maximum of 3 mg/L. It is less effective than chlorine and therefore needs a higher initial dose and longer contact time. Unlike chlorine, monochloramines do not add any taste or smell to the water. Types of Chloramine:There are 3 forms of inorganic Chloramine; monochloramine, dichloramine and trichloramine. All of these can be formed when water containing or injected with ammonia is chlorinated. The pH and the ammonia/ chlorine ratio determine which kind of chloramines is formed. At a pH <3 mainly trichloramine is formed, at pH 4-7 mainly dichloramines is formed while at a neutral pH >7 or above monochloramine is the main form produced. Three types of chloramines are generally formed when different ratios of chlorine and ammonia are added to water. Dichloramine is a stronger disinfectant than monochloramine (the most common type used) but is less stable and has a distinct disagreeable odour. Nitrogen trichloride has an extremely offensive odour but is readily destroyed by sunlight. Monochloramine is a weak disinfectant used extensively in the US requiring 25 to 100 times the contact time of free chlorine for equivalent disinfection however chloramines stay longer and continue to disinfect in the extremities of long pipeline distribution systems than chlorine. Back to Top


Is present in just about all natural waters. Sodium chloride is widely used in the production of caustic soda, chlorine; sodium chlorite and sodium hypochlorite. The taste threshold of chloride in water is in the range of 200-300 mg/L. In surface water, the concentration of chloride is usually below 100 mg/L and frequently below 10 mg/L. Food is the major source of chloride intake particularly if salt is added during processing or cooking. All plants and animals contain chloride. Based on taste considerations chloride concentration in drinking water should not exceed 250 mg/L. Chloride is essential for humans and animals. It contributes to the osmotic activity of body fluids. A normal 70 kg human body contains approximately 80 grams of chloride. Back to Top


A chemical compound available in a gas, liquid, granular or powder form used for disinfecting water. It is a strong disinfectant and bleaching agent and is effective with short contact times. It is also a strong oxidizing agent and can oxidise iron and manganese and remove the taste and odour produced by some algae. Chlorine has an odour threshold in drinking water of approximately 0.6 mg/L although sensitive people can detect it as low as 0.2 mg/L. Based on health considerations the maximum free chlorine level should not exceed 5 mg/L. In Australia most drinking water supplies range from 0.1 mg/L to 4 mg/L with a typical average of 0.2 mg/L. Refer to water quality in your suburb. Back to Top

Chlorine dioxide

Is a reactive gas that cannot be easily stored or transported and must be generated or made on site. Chlorine dioxide is a more effective disinfectant than chlorine with little to no formation of chlorinated by-products such as THM’s. The effectiveness increases about three fold between pH 6 and 9. Back to Top


A disinfection process in water treatment where chlorine is used to sanitise the water. It is the most popular method of drinking water treatment and usually leaves 0.2 to 0.8 ppm of free chlorine in the water. Chlorine, although a poisonous gas, is a strong oxidizing agent and therefore an excellent disinfectant. However the by-products of chlorination eg THMs can produce cancer in humans. Back to Top


A metallic element found naturally in the environment in the trivalent and hexavalent states. It increases the harden ability of steels and is present in stainless steels because of its corrosion resistance. Trivalent chromium is the most common naturally occurring state. Most soils and rocks contain small amounts of chromium oxide. Weathering, oxidation and bacterial action convert this insoluble compound into soluble salts. Trivalent chromium salts are used in leather tanning, manufacture of catalysts, paint pigments, fungicides and ceramic and glass manufacture. Trivalent chromium is an essential trace element for humans, with food being the major source of intake. Hexavalent chromium also occurs frequently in nature. Its presence in water is generally the result of industrial and domestic chromium waste discharges. Hexavalent chromium compounds are used in the metallurgical industry for chrome alloy and chrome metal production and in the chemical industry as oxidizing agents. Hexavalent chromium is not considered to be an essential element for humans with harmful effects due to chromium being attributed to this form. Based on health considerations the concentration of hexavalent chromium in drinking water should not exceed 0.05 mg/L. Back to Top


Is a very fine grained soil of colloid size (0.01 – 1.0 microns) consisting mainly of hydrated silicate of aluminium. Back to Top


Causes colloidal particles (0.01 – 1.0 microns) to clump together into large groups where they fall to the bottom of the vessel. Back to Top


Are small bacteria, many of which are able to multiply in water to high numbers given the right conditions. Coliforms are most likely to be present in reticulated water supplies when the water has not been treated or disinfected, or when treatment has not been adequate. Types include Escherichia Coli (E coli) and Klebsiella. Back to Top


Are organic particles smaller than 0.002mm and larger than 0.000001mm. Particles less than 0.002 mm settle in water very slowly or not at all. Back to Top


This term is used in conjunction with reverse osmosis water filters and refers to the reject water or water that goes to drain or waste. This water has a high or concentrated amount of impurities not able to pass through the filter membrane. This water may still be suitable for use but is of lower quality than the incoming/feedwater and the pure filtered water (permeate). Back to Top


A soft reddish brown metallic element that is an excellent conductor of electricity and used extensively for electrical wiring and water piping. It is also used in many household goods and in the chemical industry; copper sulphate is used to control the growth of algae in rivers and water storages. Copper is widely distributed in rocks and soils and is in most surface waters in very low concentrations. The taste threshold for copper is generally 3 mg/L. Concentrations above 1 mg/L may cause blue or green stains on tapware and basins. Copper is an essential trace element for humans with the main source of copper intake being food with small amount taken in through water. Copper can be removed from drinking water by increasing the pH followed by coagulation and filtration. The concentration of copper in drinking water supplies should not exceed 1 mg/L. Back to Top


Is a type of protozoa. This cyst is small in size (4-6 microns) and is best removed from water supplies by filtration. It has a hard outer shell which makes it extremely resistant to disinfection even with chlorine rates up to 1000 ppm. Human infection by Cryptosporidium can result in diarrhoea and other ill effects. Back to Top


A chemical compound found naturally in soils and plants although highly toxic in potassium cyanide and sodium cyanide forms. Cyanides are used in plastics and the extraction of gold and silver from low grade ores. It is also used in the electroplating steel and chemical industries. Green almonds and improperly prepared cassava plants can have high concentrations of cyanide, long term consumption can lead to health complications. Based on health considerations, the concentration of cyanide in drinking water should not exceed 0.08 mg/L. Back to Top


Or protozoan cysts are found in many freshwater streams and storages. Most of these organisms are of no significance to health and generally feed on other micro-organisms such as bacteria, cyanobacteria or algae. Some protozoa have life stages alternating between proliferative (trophozoites) stages and dormant cysts. As cysts, protozoa can survive harsh conditions such as exposure to extreme temperatures or strong chemicals, or long periods without nutrients, water or oxygen. Being in a cyst form also allows protozoa to survive outside of a host or move from one host to another. When protozoa are in the trophozoite form they actively feed and grow. The protozoa that can be found in Australian drinking water causing adverse health effects fall into the following two groups:
  • Enteric protozoa which occur widely as parasites in the gut of human and other mammals and include cryptosporidium, Giardia and Entamoebe histolyitca.
  • A few free living organism which are opportunistic pathogens in humans and are responsible for serious cerebral and eye diseases. These include: Naegleria and Acanthamoeba.
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Demineralised/De-onised Water

Has had its total dissolved and suspended solids removed by distillation, reverse osmosis and or ion exchange filters. Back to Top


Is the removal of dissolved salts from water. This is usually for making drinking water from sea water and carried out with reverse osmosis filtration systems using special membranes. Back to Top

DI Water

Is deionized water. This water has been distilled or treated with a reverse osmosis filter followed by ion exchange filters to remove remaining impurities. This water is very pure with very low electrical conductivity. Back to Top

E Coli

Escherichia coli is a thermo tolerant (heat tolerant) or faecal coliform bacteria usually caused by faecal pollution of the water supply. The strains of this bacteria cause diarrhoea and other cholera like symptoms requiring medical attention. Back to Top

EC (Electrical Conductivity)

Is a standardised measurement of electrical conductivity or level of salts (salinity) contained in water corrected to 25°C. Back to Top


The conduction or movement of electric current through electrolytes (free ions in solution). Direct current (DC) causes metal or hydrogen to be released at the cathode and acid radicals or oxygen at the anode. Back to Top


This term is used in conjunction with reverse osmosis water filters and refers to the inlet water or the water that is supplied to the reverse osmosis unit to be filtered. Back to Top

Filter Cartridge

A cylindrical shaped item containing various types of filtration media designed to remove or reduce impurities in water. Cartridges are usually 9”, 10” or 20” long x 2” - 4.5” in diameter. They usually fit inside a housing or outer casing creating a water tight filtration system. The media is generally designed to absorb/trap and hold/contain the impurities until the end of its rated life. Back to Top


Is the removal of solids from a liquid, gas or air. This is usually done with some sort of media or membrane. Back to Top


A mixing process by which suspended material or very fine particles are assembled into larger masses of flocs (clumps) which then settle out of suspension. Back to Top

Flow Rate

This is the amount of water that is able to pass through or discharge from a filter in a given period of time and is usually expressed in litres/second, litres per minute or litres per hour, i.e. 8.5 litres/minute means the filter can treat 8.5 litres of water per minute to the nominated standard. Back to Top


An organic or inorganic compound containing the element fluorine. The organic form occurs naturally in seawater and soil. Concentrations in surface water are generally quite low (0.1 – 0.5 mg/L) while water from deep bores can have quite high concentrations (1 – 10 mg/L) if the rock formations are fluoride-rich. Inorganic fluorine compounds are generally a by-product of aluminium production and used in the steel, fertilizer and ceramic industries i.e. brick, tiles, etc. Virtually all food contains traces of fluoride with high amounts in tea leaves. Inorganic fluoride in a corrosive dangerous chemical injected into many town water drinking supplies because it is said to enhance dental health. It is also present in most brands of toothpaste. The target fluoride concentration in fluoridated water supplies is between 0.7 mg/L and 1 mg/L. Lower concentrations are used in warmer areas to allow for higher water consumption. Based on health considerations, the concentration of fluoride in drinking water should not exceed 1.5 mg/L. Concentrations above 1.5 mg/L can lead to dental fluorosis (a tooth decay and mottling of teeth enamel). High concentrations can also cause brittle bones and skeletal fluorosis. People with reduced kidney function should also be careful as they can retain the fluoride at 3 times the rate of a normal person. Back to Top

Foot valve

A check valve located at the bottom or end of a pump suction line designed to hold water in the pump suction between operating events. Back to Top


Weather during which dew is deposited as ice. Water expands by about 9% of its volume when it freezes. Back to Top


Is a type of protozoa. This cyst is small in size (3-5 micron) and can be removed from water supplies by filtration or disinfection with chlorine, chloramines, chlorine dioxide or ozone. It is a lot less resistant than cryptosporidium to chlorine although more resistant than most bacteria. Infection by Giardia may reduce absorption of nutrients in the intestines and cause diarrhoea. Back to Top


Is the chemical symbol for water. Each molecule of water contains 2 atoms of hydrogen joined to a single atom of oxygen. Water is the most abundant molecule on the earth’s surface covering nearly 75%. In its pure form it is colourless and tasteless. Back to Top


Is generally the level of calcium and magnesium irons present in the water although other cations such as strontium, iron, manganese and barium can also contribute. Hard water requires more soap than soft water to obtain a lather or soapy bubbles. It can also cause scale to form on hot water appliances, air conditioners, etc. Back to Top

Hydrogen Peroxide

Or H2O2 is an effective disinfectant and can be used for small drinking water supplies or emergency applications. It is also widely used to sanitise water filtration systems and equipment although correct dosage and use is important due to its low biocidal effect. After sanitizing it breaks down into water and oxygen. Back to Top

Hydrogen Sulfide

A colourless, toxic and flammable chemical compound/gas that smells like rotten eggs. Hydrogen sulfide is formed in drinking water by the hydrolysis (a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions) of soluble sulfides or through the reduction of sulfate by the action of micro-organisms under anaerobic/anoxic conditions. Hydrogen sulfide can therefore be removed from drinking water by keeping the water well oxygenated. Hydrogen sulfide has a taste and odour threshold of 0.05 mg/L, therefore concentrations in drinking water should not exceed this level. Hydrogen sulfide is used industrially in the production on sulfur, sulfuric acid, inorganic sulfides and other organic chemicals. It also occurs as a by-product in a number of processes such as petrol refining, paper mills, iron smelters, food processing and tanneries. However it is possibly known most for its presence in sewers where it can be a major problem and source of odour. Back to Top

Inline Filters

These water filters are designed to be installed or cut into the water supply line with the water flowing in one end through the filtration media and out of the other end. They are generally quick connect requiring little or no tools and sized between 6 and 12 mm inlet/outlet. When the filters is changed, the complete unit is removed from the line and replaced. Inline water filters are used on reverse osmosis systems, ice makers, fridges, bubblers and other beverage equipment. Back to Top

Inorganic Compounds

Are all non carbon based compounds. They as well as oxides and sulphides of carbon and metallic carbides. Include metals, gases such as carbon dioxide, oxygen etc and minerals such as silicon, limestone, etc. Back to Top


A natural occurring element in seawater, seaweed, cows milk, seafood and nitrate minerals. It is mostly found in nature in the form of iodide which can be oxidised to form iodine. It can also be found in the form of iodates and periodates. Iodine solutions are used as antiseptics and sanitising agents, germicides and dyes. It can also be used for emergency disinfection of small water supplies; it is not popular though due to taste and is not recommended for regular use due to possible health effects with long term consumption. Iodide is used in pharmaceutical and photographic materials. Based on health considerations, the concentration of iodide in drinking water should not exceed 0.1 mg/L. No concentration levels have been set for iodine. Iodine is considered an essential trace element for humans and is used in synthesis and thyroid hormones. The recommended dietary intake for adults ranges from 0.03 mg/day to 0.15 mg/day. Iodine is absorbed by the gastro-intestinal tract and deposited in the thyroid gland, the eye and muscles tissue. More than 70% of the bodies intake is found in the thyroid gland. Very high doses of iodine (over 30 mg/kg body weight can be lethal to humans). Back to Top

Ion Exchange

The chemical exchange of an undesired dissolved substance for another. Water softeners take in calcium and magnesium in exchange for the sodium (salt) they give out. This exchange is done with iron exchange resin media. Back to Top

Ion Exchange Resins

There are many types of synthetic resins available to remove any number of dissolved substances from water including minerals, heavy metals and fluoride. Once their removal capacity is reached they are disposed of, flushed or regenerated with acid or caustic soda. Back to Top


A metallic element occurring naturally in soil and rocks in the form of iron oxide, iron sulphide or carbonate minerals. In water it is in ferric (Fe III) form or Ferrous (Fe II) form. Iron is used in iron and steel products, paint pigments, food colours and health supplements. Iron sulphate is also used as a flocculant in water treatment. Iron is often present in surface waters and ground water bores. Iron has a taste threshold of 0.3 mg/L in water and becomes objectionable above 3 mg/L. Water supplied through rusting iron pipes can have concentrations of 5mg/L or higher. Concentrations in drinking water however should not exceed 0.3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of basins and fittings. Growths of iron bacteria (which concentrate iron) may cause taste and odour problems and may lead to pipe restrictions and blockages. Iron is an essential trace element for humans. Food is the major source of iron intake and is a natural constituent in plants and animals. Fish, green vegetables and tomatoes have a high iron content. Minimum daily requirements are estimated at 14 mg/day for women aged 11-50 years and 7 mg/day for men aged 11-50 years. Iron is used in the human body to transport oxygen in the blood. It is also used in the production of haemoglobin, myoglobin and a number of enzymes. It is stored in the spleen, liver, bone marrow and muscle. Back to Top


A soft, malleable heavy metal metallic element mined from the ground widely throughout the world. It is used in production of lead acid batteries, solder, alloys, cable sheathings, paint pigments, rust inhibitors, ammunition, glazes and plastic stabilisers. Lead can be present in drinking water from natural ground based sources or from household plumbing systems containing lead. With household sources the amount depends upon the type and age of pipes, water pH and hardness. Lead is a cumulative poison that can severely affect the human central nervous system. Lead can be absorbed by the body through inhalation, ingestion or placental transfer. In adults, approximately 10% of ingested lead is absorbed but in children this figure can be 4-5 times higher. Studies conducted suggest that exposure to lead can adversely affect intelligence, result in kidney damage and interfere with the production of read blood cells and the metabolism of calcium needed for bone formation. Based on health considerations, the concentration of lead in drinking water should not exceed 0.01 mg/L. Lead concentrations in drinking water can be reduced by coagulants or lime softening during water treatment. The majority of humans daily intake of lead, although very low is from the ingestion of food, dirt and dust. Back to Top


A hard, brittle metallic element used in the manufacture of iron, steel and other alloys. It occurs in many minerals in the environment although it is present in very low concentrations in uncontaminated rivers and streams. High concentrations can be found in polluted rivers under anaerobic conditions in deep lakes or ground water. Manganese is found in the environment in he divalent, tetravalent and heptavalent states. The divalent and heptavalent compounds are generally soluble in water while the tetravalent compounds mainly manganese dioxide is insoluble. At concentrations exceeding 0.1 mg/L, manganese gives an undesirable taste to water and stains plumbing fixtures and basins. Even at concentrations of 0.02 mg/L, manganese will form a coating on pipes resulting in a black discharge into the water. Micro-organisms present in the water can also concentrate manganese resulting in taste, odour and colour problems. Manganese interferes with the DPD method for determining chlorine residual, resulting in an over estimation of the residual so that chlorine appears to be present when in fact it may not be. Manganese is present in many foods particularly in grains, nuts and vegetables with tea leaves having the highest concentration. Manganese is an essential element and is required for normal growth. Deficiency affects bone and brain development along with reproduction. Studies estimate the average dietary intake of manganese is 2-4 mg per day. Owing to the low solubility of manganese in gastric juices, only 3-8% of ingested manganese is absorbed by the gastro-intestinal tract, the remainder passes through the body. Of that ingested the majority is concentrated in the liver before it too passes through the body. Manganese in drinking water can be reduced or removed by converting soluble forms to insoluble precipitates whereby it can then be filtered out. Chlorine can also be used to oxidise some forms of manganese or lime softening at high pH levels. Back to Top


Refers to the materials contained within the filter used to remove the required impurities. This can be a combination of different materials including carbon, ion exchange resin, KDF, calcite, polyphosphate, etc. Back to Top


A silvery white poisonous metallic element which is liquid at room temperature and widely used in electrical components, batteries, switches, lamps, thermometers, barometers, pesticides and fungicides. It is also used in dental amalgams, antiseptics, preservatives and pharmaceuticals. Natural occurring mercury very rarely enters the food chain or drinking water supplies. Most contamination comes from industrial emission or spills. Mercury compounds fall into two categories, inorganic mercury salts (generally insoluble in water) or organic mercury compounds. Food is the main source of exposure for humans with the highest concentrations found in fish and fish products. Australian adult dietary intake of mercury is approximately 0.004 mg per day. The concentration of total mercury in drinking water supplies around the country is typically less than 0.0001 mg per litre ranging up to 0.001 mg per litre. Granular activated carbon is generally used to remove organic and inorganic mercury from water. Inorganic mercury is absorbed by the gastro-intestinal tract accumulating in the kidney. Toxicity results in damage to the kidneys and central nervous system. Generally less than 15% of inorganic mercury in drinking water will be absorbed as opposed to organic mercury where almost all is absorbed by the gastro-intestinal tract. The effects are also more severe than those of inorganic mercury. Based on health considerations, the concentration of total mercury in drinking water should not exceed 0.001 mg per litre. Back to Top


A layer of material that acts as a barrier between two liquids allowing specific particles, molecules or substances to pass through when water pressure is applied to one of the liquids. Back to Top


Milligrams per litre is the measure of the proportion or concentration of a particular chemical or compound in a solution. Back to Top

Micro filtration

A filtration process able to filter down to 0.05 microns, generally using filter cartridges which are thrown away. Back to Top


A unit of measure, one thousandth of a millimetre, 0.001 mm. Back to Top


Is a metallic element used to strengthen alloy steels and soften tungsten alloy. It is also used in fertilizers, spark plugs, dyes, enamels and reagents. Molybdenum compounds are used as lubricants in oils and greases. Molybdenum is an essential trace element for humans with an estimated requirement between 0.15 – 0.5 mg per day for adults. Many foods contain significant amounts of molybdenum including legumes, grains and liver. Molybdenum is found in ground and surface waters at very low concentrations, generally under 0.01 mg per litre. Based on health considerations the concentration of molybdenum in drinking water should not exceed 0.05 mg per litre. Back to Top


Is a chemical compound used as a disinfectant for drinking water supplies. It is an alternative to chlorine that is becoming more widespread in Australia. Although it is less effective than chlorine it stays in the water longer making it better for use in long water supply pipelines. It also has a lot less by-products such as THM’s (Trihalomethanes). Concentrations in drinking water supplies usually range from 1.5 to 2.5 mg per litre and should not exceed 3.0 mg per litre. Average residual concentrations are about 0.5 mg per litre. Monochloramine, dichloramine and trichloramine can all be formed when ammonia and chlorine are added to water. The pH of the water effects which compound is formed. Monochloramine is the most common with lower odour and taste issues. Odour can usually be detected at concentrations over 0.5 mg per litre. Monochloramine can be removed from drinking water by granular activated carbon although longer contact times are required and filter capacities are usually substantially de-rated with many filters unsuitable. Sodium sulphite or sodium bisulphate can also be used. Back to Top


A hard silvery metallic element that is resistant to corrosion. It is used in alloys in the chemical, marine, nuclear and aerospace industries and in the electroplating industry. It is also used as a catalyst in industrial processes and in oil refining. Nickel is present in many foods with highest concentrations in cocoa, soy beans and some cereals/grains. Drinking water supplies in major Australian cities have concentrations up to 0.03 mg per litre with typical concentrations less than 0.01 mg per litre. Based on health considerations, the concentration of nickel in drinking water should not exceed 0.02 mg per litre. It can however be removed from drinking water and co-precipitated with iron and manganese oxides. These can then be removed as sludge or filtered out. In humans intestinal absorption of soluble nickel in drinking water can be as high as 27% compared with only 0.7% from food. After absorption, nickel appears to be distributed to most organs, with higher amounts in the kidneys, lung and liver. Long term exposure can result in toxic effects and cancer. It is also known to be a common skin allergen causing dermatitis in more sensitive people. Inhalation of nickel can cause lung, sinus and nasal cancer. Back to Top


A naturally occurring salt that dissolves easily in water and is an important part of the nitrogen cycle. They are also naturally occurring irons formed from the oxidation of organic wastes such as manure or by the action of nitrogen fixing bacteria in soils. Nitrates are manufactured for use in explosives and inorganic fertilizers. Farming practice’s and sewage effluent disposal to streams have led to increasing amounts of nitrate in some surface and ground waters. Drinking water supplies in major Australian cities can have nitrate levels up to 18 mg per litre with typical concentrations usually less than 0.15 mg per litre. Based on health considerations, levels should not exceed 50 mg NO3 per litre. Food particularly vegetable and cured meat is the major source of nitrate intake for humans. Nitrate removal in water supplies can be done with the use of anion exchange resins. The toxicity of nitrate to humans is thought to be solely due to its reduction to nitrite. The nitrite iron is unstable and can be formed by the reduction of nitrate in poorly oxygenated water. The major biological effect of nitrite in humans is its involvement in the oxidation of normal haemoglobin (the protein found in blood) to methaemoglobin which is unable to transport oxygen to the tissues and organs of the body. Young infants are more susceptible to methaemoglobin formation then older children and adults. Back to Top


Is a toxic substance that is produced by the oxidation of ammonia or formed by the reduction of nitrate in poorly oxygenated waters. Nitrites are used as food preservatives and colour enhances and have the chemical form of NO2. They are a naturally occurring iron and an important part of the nitrogen cycle. The nitrite iron is unstable and is normally rapidly oxidised to nitrate and is therefore seldom present in well oxygenated or chlorinated drinking water supplies. Chemical and biological processes can result in further reduction to various compounds including ammonia. Based on health considerations, the concentration of nitrite in drinking water should not exceed 3 mg NO2 per litre. Back to Top

Nominal Rating

Is the approximate grade or level of filtration delivered. This nominal rating means 60-98% of particles larger than the filter rating (usually in microns) will be removed or entrapped on or within the filter medium. As opposed to an absolute rating. Back to Top

Online Filters

These water filters are designed to be installed near the supply line. The supply line is then diverted to the filter, the water then passes through the filter before being diverted back to the supply line or discharge point. The filter cartridges are then normally changed rather than the entire filter as is the case with inline filters. Back to Top

Organic Compounds

Carbon based compounds, organic compounds are the basis of all living matter, and include plant material, amino acids, oil and its derivatives, etc. Back to Top


Is the diffusion of a solvent or diluted liquid through a membrane (permeable in only one direction) into the more concentrated solution. Back to Top


A poisonous blue gas used for disinfection of drinking water and sanitation of swimming pools and spas. It is an excellent disinfectant and completely decomposes to oxygen in an hour or less leaving no residual. It is generated on site and injected straight into the water. It is also used extensively in the treatment of bottled water. Naturally generated ozone also forms the ozone layer in the earth’s stratosphere, 10-35 km above earth’s surface. It absorbs ultra-violet rays protecting life form. One molecule of chlorine can destroy 100,000 ozone molecules. Back to Top


This term is used in conjunction with reverse osmosis water filters and refers to the pure filtered water that has passed through the membrane and had the impurities removed. Back to Top

pH Scale

The chemical way of measuring acidity and alkalinity, on a scale of 0 to 14. Neutral is pH 7.0. 7 to 14 is alkaline with 14 being the most alkaline. Below 7 indicates acidity with 0 being the most acidic. Back to Top

Potable water

Is water that is suitable for human consumption or drinking having met or exceeded Australian drinking water guidelines; world health organisation (WHO) guidelines or similar local standards or guidelines. Back to Top


Point of entry filtration refers to a water filter that is installed on or at the entry to a house or building thereby treating all water going into the building or premises. Back to Top


Point of use filtration refers to a water filter that is installed on or at a particular outlet. Treating the water at this particular outlet rather than all outlets in a house or building. Back to Top


Parts per million is a measure of the proportion or concentration of a particular chemical or compound in a solution i.e. 1 part per million = 1 litre per million litres or 1 mg/L. Back to Top


Force per unit area usually expressed in kpa or psi. Back to Top

Pressure Differential (PD)

This is the difference in pressure between the inlet and outlet of a filter and is used to indicate when the filter is getting blocked. As a filter gets more and more blocked the pressure difference between the inlet and outlet gets greater. When the filter gets completely blocked the inlet pressure will be high and the outlet pressure will be very low or zero. A pressure differential can also be caused by flow rate through a filter. The higher the flow rate through a filter the greater the pressure differential as the water requires more and more pressure on the inlet side to get through. Back to Top

Pressure Drop

This can have the same meaning as pressure differential or can refer to a decrease (drop) in pressure between the inlet of a building or pipeline and the outlet or tap. This pressure drop is mainly caused by pipe friction, valves and fittings losses. Back to Top

Pressure gauge

An instrument for measuring fluid pressure. Back to Top

Pressure tank

A tank containing a bladder/balloon used for water storage on pump systems or reverse osmosis filtration systems. The outside of the bladder is pumped up with a low air pressure thereby forcing the stored water out when required on demand. Back to Top


Is a single celled organism that can only divide within a host organism. Cryptosporidium and Giardia are protozoa. Most are too small to be seen with the naked eye ranging in size from 0.01 to 0.05mm but can be as big as 0.5mm. Back to Top

Residual chlorine

The amount of free chlorine remaining in the water to kill or sanitise organic matter. Back to Top

Reverse Osmosis

A water filtration process using a membrane to filter out chemicals and organic matter down to 0.0005 microns including bacteria and viruses. It is able to reduce total dissolved solids (TDS) by up to 99% producing very pure water. For every litre of water filtered they waste between 1 and 6 litres although this waste water can be used. Back to Top


A measure of the concentration of inorganic salts in a liquid. The electrical conductivity of a solution provides a convenient means of measuring salinity. The units of electrical conductivity are micro Siemens/cm, commonly referred to as EC units or inorganic total dissolved solids. Back to Top


Involves cleaning a water filter or piece of equipment with an antibacterial solution such as chlorine, hydrogen peroxide, bleach etc to remove and kill bacteria, dirt and other contaminants. This is usually undertaken every 3-12 months. Back to Top


Is a coating or deposit that forms on the inside of equipment such as kettles, coffee machines, hot water units, steam ovens, etc. It is caused by carbonates or bi-carbonates in the water such as calcium and magnesium. These can be removed by specific filtration or the equipment protected by adding scale inhibitors to the water supply. Back to Top


Is any material that settles in a liquid. Back to Top


Is a non-metallic element widespread in the environment. Selenium and selenium salts are released from natural and man-made sources with the main sources being the burning of coal and as a by-product of the processing of sulphide ores in the copper refining industry. The major use of selenium is in the manufacture of electronic components such as semi-conductors, photovoltaic and solar cells, hair shampoos, insecticides and as a nutritional feed for poultry and livestock. Selenium is an essential trace element for humans forming proteins that help prevent damage to cells in the body by oxidants. Deficiency in humans can cause heart muscle and heart disease. Too much selenium can cause temporary balding, brittle nails, weakness and slowed mental functioning. Food is the major source of intake for Australians. Cereals and grain products contribute most to intake, while fish and liver contain the highest selenium concentrations. The average daily intake for Australian adults is between 0.06 mg and 0.13 mg. Selenium concentrations in water supplies are generally low (less than 0.005 mg/L) and are dependent upon pH, other iron salts and local geology. Based on health considerations, the concentration of selenium in drinking water should not exceed 0.01mg/L. Most water soluble selenium compounds are absorbed by the gastro-intestinal tract. Selenium is then distributed to most organs with the highest concentrations found in the kidney, liver and spleen. Selenium concentrations in drinking water or water supplies can be reduced by coagulation with ferric chloride or lime softening. Activated alumina absorption is the most effective method of removal but only at low pH. Back to Top

Semi-permeable Membrane

A filtration membrane used in reverse osmosis systems that is permeable or only allows water through in one direction. Back to Top


Is a soft precious metallic element having the highest electrical and thermal conductivity of any metal. It is used in tableware, jewellery, coins, batteries, mirrors, photography and as an antiseptic agent. Silver concentrations in natural water sources are generally very low; less than 0.0002 mg/L. Traces of silver can also be found in most foods with the average Australian dietary intake estimated between 0.03 and 0.09 mg/day. Based on health considerations, the concentration of silver in drinking water should not exceed 0.1 mg/L. It can also be removed from drinking water by coagulation, lime softening, KDF and other special media. Silver is not considered an essential trace element for humans. The small amount of dietary silver (<10%) absorbed by the gastro-intestinal tract is stored mainly in the liver and skin. Silver toxicity results in a bluish grey metallic discolouration of the skin, hair, mouth and eyes. Silver is a weak biocide that has been used over the centuries and is still used occasionally or in specific instances for disinfection of drinking water supplies on a small scale or with direct use equipment. High rates are required if used on its own although it is often used in conjunction with hydrogen peroxide or copper. It is also used in carbon cartridge filters to deter bacteria growth within the cartridge. Back to Top


Is a soft white metallic element found in abundance throughout the world. It is the sixth most abundant element on earth. Sodium irons are widespread in water due to the high solubility of sodium salts and the abundance of mineral deposits. Sodium salts are used in the paper, glass, soap, pharmaceutical and chemical industries. Bleach, chlorine, table salt and other food products are the main source for domestic consumption. Sodium is an essential element for humans with food being the major source. In Australia the average dietary sodium intake has been estimated at 4g/day. In major Australian drinking water supplies, sodium concentrations vary from 3 mg/L to 300 mg/L with an average value of 50 mg/L. Sodium such as sodium chloride or sodium sulphate have a taste threshold of about 135 mg/L with a noticeable taste when the sodium concentration exceed 180 mg/L. Based on taste considerations, the concentration of sodium in drinking water should not exceed 180 mg/L. Excess concentrations are usually removed by Reverse Osmosis or distillation treatment methods. Virtually all sodium consumed (food or drink) is absorbed by the human body. Sodium is present in all body tissues and fluids and its concentration is maintained by the kidneys. Increases in the sodium concentration in plasma (blood) gives rise to the sensation of thirst. Excess sodium intake can lead to health problems particularly with the heart. Excess sodium is normally removed from the body in urine. Back to Top

Solenoid valve

A valve opened or closed by a small electrical current. The solenoid has an actuator/plunger inside encircled by a coil of wire through which a current passes to strengthen or reverse the magnetism thereby opening or closing the valve. Back to Top

Spring Water

Is water obtained from a natural underground water source flowing to the surface. The majority of bottled water on the market is not spring water and is in fact filtered town water. This is the case with any bottled water that has “still water” written somewhere on the label. Back to Top


Is a chemical compound containing the sulphate iron occurring naturally in a number of minerals. Sulfate is used commercially in the manufacture of numerous products including chemicals, dyes, glass, paper, soaps, textiles, fungicides and insecticides. Sulfate including sulphuric acid, is also used in mining, pulping and the metal and plating industries. Barium sulphate is used as a lubricant in drilling rigs for ground water supply. Aluminium sulphate was used extensively and still is used as a flocculent in town water treatment plants around Australia. Copper sulphate is used for the control of blue-green algae in rivers and water storages. Food is usually the major source of intake of sulphate although sulphate can leach naturally from rocks and cause higher concentrations in drinking water. Even with this though it is typically less than 100 mg/L. Based on taste considerations, the concentration of sulphate in drinking water should not exceed 250 mg/L. In most major drinking water supplies around the country it is less than 30 mg/L but can range between 1 – 240 mg/L. Removal of excess sulfates is usually by Reverse Osmosis or distillation. Sulfate in drinking water supplies can interfere with disinfection efficiency by scavenging residual chlorine as well as causing corrosion of pipes and fittings. Sulfate is rapidly absorbed by the gastro-intestinal tract and found in all body tissue with the highest concentrations in the bone and teeth areas where it is thought to help with formation and regulation of development. Back to Top


Is a silvery malleable metallic metal element that resists corrosion. It is used in many alloys such as solders, bronzes, pewters and to coat other metals to prevent corrosion. Tin coatings are used in the manufacture of food containers and in food processing equipment. Inorganic tin compounds are used as pigments in the ceramic and textile industries while organic tin compounds are used as biocides. Food, in particular canned food is the major source of human exposure to tin. Ingestion from this source can range from 0.1 mg/day up to 100 mg/day with an average of 0.2 mg/day. Tin or tin salts are poorly absorbed (less than 5%) from the gastro-intestinal tract. Of that absorbed, the highest concentrations are found in the bone, kidney and liver. Back to Top

Total Dissolved Solids (TDS)

A measure of the quantity of dissolved solids in a given volume of water. They consist of inorganic salts and small amounts of organic matter that are dissolved in water. Total dissolved solids comprise sodium, potassium, calcium, magnesium, chloride, sulphate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphate. Less than 80 mg/L is considered excellent, 80-500 mg/L is considered good and 500 – 800 mg/L is considered fair. Back to Top

Trihalomethans (THM’S)

Are disinfection by-products formed by adding chlorine, chloramine or bromine to water. In Australia THMs are present in drinking water principally as the result of treating drinking water with chlorine or chloramine. Chlorine, which produces hypochlorous acid when added to water reacts with organic matter in the water to produce trihalomethanes. The brominated (bromine) trihalomethanes are produced by the oxidation of bromide present in the water to from hypobromous acid which then reacts with organic matter in the water in the same way as chlorine. In major Australian drinking water supplies concentrations of total trihalomethanes range up to 0.6 mg/L. Based on health considerations, the concentration of THM’s (either individually or in total) in drinking water should not exceed 0.25 mg/L. High THM concentrations may also indicate the presence of other chlorination by-products such as chloroform. THM’s can be reduced by removing as much organic matter from the water prior to chlorination or THMs can be removed after chlorination by activated carbon filters. Chloramine, ozone and chlorine dioxide disinfection also produce substantially less THM concentrations, than chlorine. THM’s are rapidly and efficiently absorbed by the human body following ingestion. They are metabolised primarily into carbon dioxide and or carbon monoxide and exhaled or accumulated in the brain, kidney and blood. THM’s depress the central nervous system, are toxic to the liver and kidney and cause cancer. Back to Top


Is a measurement of the clarity or how clear the water is. A measure of the cloudiness or amount of suspended solids/matter such as clay, silt, colloidal particles, plankton and other microscopic organisms. A turbidity meter measures the amount of light scattered by the suspended particles present in the sample and compares this to a known calibrated value to calculate the turbidity of the sample in Turbidity Units or NTU. Most town water is less the 2 NTU with the remainder less than 5 NTU. Back to Top


Is a lower pressure membrane filtration system similar to Nano and Reverse Osmosis Systems. The membranes are not as fine as reverse osmosis filtering down to 0.002 microns. They are often tubular membranes which are normally backwashed and cleaned at set intervals. Apart from backwashing they waste little water with a low rejection rate. Back to Top

Ultraviolet Radiation (UV)

Ultra violet light is a natural part of sunlight. Back to Top

UV lamp/tube

Is an ultra-violet lamp or light tube/gas discharge lamp that uses electricity to excite mercury vapour. The excited mercury atoms produce short wave ultra-violet light that then causes phosphor to fluoresce producing visible light. Back to Top

Vinyl chloride

Is an organic compound used in the production of PVC pipe (poly vinyl chloride) plastics, rubber, paper and glass industries. Vinyl chloride may be present in drinking water through pollution, chemical spills, water stored in PVC containers or when PVC piping is used. Concentrations up to 0.01 mg/L have been reported in drinking water supplies that use PVC pipes. In Australia these types of pipes are not used in town water supply systems but are more common on rural properties. No safe concentration for vinyl chloride in drinking water has been set, levels should be below detection currently 0.0003 mg/L Vinyl chloride is a well documented human carcinogen or cancer causing compound. Tumours in the liver, brain and lung have been reported along with many other health issues. Back to Top


A micro organism smaller than bacteria ranging in size from 0.01 to 0.09 microns which cannot grow or reproduce away from a living cell. A virus invades living cells to keep itself alive and replicate itself. They can replicate exactly or with errors causing mutations and difference in the disease from person to person. Back to Top

Water hammer

Any sudden very high pressure in a pipe caused by stopping the flow too rapidly. This can result in damage to the pipeline or attached equipment. Back to Top


World Health Organisation is a specialised agency of the United Nations that acts as a co-ordinating authority on International Public Health. The WHO was established in 1948 with its headquarters in Geneva, Switzerland. WHO has 193 member states and is financed by these states and donors. The Australian Government contributes through the Department of Health and Ageing. The WHO estimates more than 1.1 billion people do not have access to clean water resulting in an estimated 88% of diarrhoea disease being attributed to unsafe water supply, inadequate sanitation and hygiene. Globally two thirds of those without reliable access to clean water live in the Asia Pacific Region. The WHO has also established Drinking Water Quality Standards and Guidelines for use globally by countries who do not have their own standards. This then enables water quality around the world to be assessed against a known or set standard. The Australian Drinking Water Guidelines and water quality standards have lower limits (in just about all criteria) than those of the WHO. Therefore if a water sample or supply complies with the Australian Drinking Water Guidelines it measurably exceeds the World Health Organisation Guidelines. Back to Top


Is a metallic element that is brittle at room temperature but malleable when heated. It is widely distributed in nature occurring in small amounts in almost all rocks. It is used to prevent corrosion of iron and steel products and in the manufacture of alloys such as brass, bronze and nickel silver. Galvanised iron, electric fuses, roofing, gutters, paint and rubber products and tyres also use zinc in the manufacturing process. In surface and ground waters, the concentration of zinc from natural leaching is usually less than 0.01 mg/L. Tap water can contain much higher concentrations as a result of corrosion of zinc coated pipes and fittings. Zinc concentrations in galvanised iron rainwater tanks are typically 2 to 4 mg/L with tests as high as 11 mg/L. Based on taste the concentration of zinc in drinking water should be less than 3 mg/L. Levels over this can given a metallic taste to the water. Zinc is an essential element for humans with a recommended intake for adults of 12 mg/day. Deficiency can result in slowed growth, anorexia, mental lethargy, skin changes and night blindness. Approximately 20 – 30% of the dietary zinc is absorbed by the gastro-intestinal tract with highest concentrations found in the liver, kidney, bones, retina, prostate and muscle tissue. Food is the major source of zinc for humans and is present in most plant and animal tissue. Dinking water provides a negligible contribution. In major Australian drinking water supplies, the concentration of zinc ranges up to 0.26 mg/L with a typical concentration of 0.05 mg/L. Excess concentration can be removed by alum coagulation at pH 6.5 – 7 (approx 30% removal) or by lime softening at pH 9.5 – 10 (approx 60% removal). Zinc toxicity can cause nausea, vomiting, diarrhoea and abdominal cramps. Back to Top