What is Total Dissolved Solids (TDS)?

Have you ever noticed a slightly salty, bitter, or metallic taste in your tap water? Or maybe your kettle has developed a chalky buildup over time? These could be signs of high total dissolved solids (TDS) in your water. But exactly what is TDS in water, and why does it matter?

TDS is the total amount of dissolved substances (both natural and artificial) in your water. These include minerals, salts, metals, and even chemicals from human activities. While some dissolved solids are harmless (or even beneficial), others can impact water quality, affecting its taste, odour, and safety.

Monitoring your TDS levels is a simple yet powerful way to make sure your drinking water is safe and clean. So, how can you check your TDS levels? What do the numbers mean? And if they’re too high, how do you fix them? Let’s find out.

What is TDS in Water?

Imagine a crystal-clear mountain spring. It looks pristine, but even this water contains naturally occurring dissolved minerals like calcium, magnesium, and sodium. In contrast, tap water from a city supply may contain chlorine, fluoride, and even trace amounts of industrial byproducts.

Total dissolved solids is the sum of all these dissolved substances. It can come from:

  • Natural sources: Minerals from rocks and soil leach into groundwater and rivers.

  • Agricultural runoff: Fertilisers and pesticides can seep into water supplies.

  • Industrial waste: Factories sometimes discharge dissolved chemicals into nearby water sources.

  • Municipal treatment: Water treatment plants add substances like chlorine and fluoride for safety and sanitation.

The key question: Just because something is dissolved in water, does that mean it’s safe to drink? Not necessarily. The type and concentration of dissolved solids determine whether your water is pure and healthy or potentially harmful.

Types of TDS

Common substances found in water include:

  • Calcium & magnesium: Essential minerals but can cause scale buildup.

  • Sodium: Contributes to salty taste if levels are too high.

  • Chloride & sulfates: Found in seawater and industrial waste.

  • Nitrates & phosphates: Common in agricultural runoff and can be harmful in high doses.

  • Heavy metals (lead, arsenic, mercury): Dangerous even in small amounts.

  • Pesticides & herbicides: Contaminants from farming and lawn care.

  • Fluoride & chlorine: Added to municipal water for health and sanitation.

Which of these are in your water? The answer might surprise you.

How is TDS Measured?

Testing your water for TDS is easy with a total dissolved solids test. Here are the two main options for how to measure total dissolved solids:

  1. Laboratory testing: Provides a precise breakdown of dissolved solids, but takes time and can be costly.

  2. At-home TDS meter: Offers a quick, convenient reading of your water’s TDS level.

While lab tests give detailed results, water quality monitors can help you regularly check your water at home, allowing you to spot potential issues early.

How Does a TDS Meter Work?

A total dissolved solids meter measures how well water conducts electricity. Since dissolved solids increase conductivity, the meter gives an estimate of the total concentration.

Here’s how to use one:

  1. Turn on the meter and remove the protective cap.

  2. Submerge the probe into a glass of water.

  3. Wait for the reading to stabilise.

  4. Compare your results to recommended TDS levels.

So, what’s a good number?

Ideal TDS Range for Drinking Water

According to the World Health Organisation (WHO), TDS levels should ideally be below 500 ppm (parts per million). Here’s a general breakdown:

  • Below 50 ppm: Very pure but may taste flat due to lack of minerals.

  • 50–150 ppm: Ideal balance.

  • 150–500 ppm: Generally safe but may have noticeable taste differences.

  • 500–1000 ppm: Could indicate contamination or excessive minerals.

  • Above 1000 ppm: Poor water quality. Filtration is necessary.

If your TDS levels are creeping towards the higher end, it’s time to take action.

How Does Total Dissolved Solids Affect Water Quality?

Ever had water that tastes overly salty or bitter? That’s total dissolved solids at work. High TDS levels can affect:

  • Taste: Too much sodium or sulfate can make water taste unpleasant.

  • Odour: Certain dissolved substances, like chlorine or algae byproducts, can create a noticeable smell.

  • Appearance: Cloudy or coloured water may indicate high TDS levels.

More importantly, unsafe TDS levels (above 500 ppm) can signal potential health risks. Contaminants like arsenic, lead, or nitrates can enter your water supply, and prolonged exposure to these substances is dangerous.

What are the Common Causes of High TDS Levels?

TDS levels can rise due to both natural and human-made factors. The most common causes include:

  • Mineral deposits: Areas with high limestone or salt deposits often have naturally high TDS in groundwater.

  • Agriculture: Fertilisers, pesticides, and animal waste contribute to nitrate and phosphate contamination.

  • Urban runoff: Chemicals from roads, factories, and industrial plants seep into local water sources.

  • Water treatment residues: Chlorine, fluoride, and other additives can raise TDS levels.

Even if your water is treated, that doesn’t mean it’s free of dissolved solids!

How to Lower TDS Levels in Water

The best solution for how to reduce total dissolved solids in water is filtration. A high-quality filter can:

  • Remove excess minerals and impurities

  • Improve taste and odour

  • Reduce reliance on bottled water (saving money and plastic waste)

For serious TDS reduction, a mixed bed resin deionising cartridge is one of the best options. This advanced filtration system effectively removes dissolved solids, giving you cleaner, healthier water.

Take Control of Your Water Quality – Test and Filter Your Water

Understanding how total dissolved solids affect water quality is key to maintaining clean, safe drinking water. A simple test with a TDS meter can tell you a lot about your water quality, and if necessary, filtration can help improve it.

Don’t leave your water quality to chance. Test it, filter it, and drink with confidence.

For expert advice on how to lower TDS in water and filtration solutions, contact AquaSafe today!