What is TDS in Water? A Complete Guide for Australians

Water quality is a major concern for many Australians, especially when it comes to drinking water. Whether you’re using tap water, bore water, or filtered water, you’ve probably heard aboutTDS levels. But what exactly isTDS in water, and why does it matter?

In this article, we’ll break downTotal Dissolved Solids (TDS), how it affects water quality, and whether it’s something you should be worried about. We’ll also explore how TDS levels compare across different water sources inAustraliaand what you can do to manage them.

TDS stands for Total Dissolved Solids , which refers to the amount of organic and inorganic substances dissolved in water. These substances include:

• Minerals (like calcium, magnesium, and potassium)
• Salts (such as sodium chloride)
• Metals (like lead, arsenic, or iron)
• Organic matter (such as algae and bacteria)

TDS is usually measured inmilligrams per litre (mg/L)orparts per million (ppm).The higher the TDS level, the more dissolved substances are in the water.

TDS levels in water can vary depending onthe source. Some common contributors include:

• Natural sources : Minerals dissolve in water as it flows through rocks and soil.
• Urban runoff : Rainwater can carry pollutants from roads, gardens, and industrial areas into water supplies.
• Agricultural activities : Fertilizersand pesticides can leach into groundwater, increasing TDS.
• Water treatment processes : Some water treatment chemicals can add to the TDS levels.
• Piping and plumbing : Old pipes can release metals like copper and lead into your water.

According to the Australian Drinking Water Guidelines (ADWG) ,TDS levels under 600 mg/Lare generally considered good for drinking. Here’s a rough breakdown:

TDS itself isn’t necessarily harmful—many of the dissolved minerals in water are actuallybeneficial for health. However,excessive TDScan lead to issues such as:

• Unpleasant taste : High TDS can make water taste salty, metallic, or bitter.
• Scaling in appliances : Hard water with high TDS can cause limescale buildup in kettles, dishwashers, and pipes.
• Potential contaminants : High TDS could indicate the presence of harmful substances like heavy metals, nitrates, or pesticides.

If you’re concerned about high TDS levels, it’s a good idea totest your water qualityand take necessary action.

Most Australian cities havemoderate to low TDS levelsin their tap water, as the water is sourced from dams, rivers, and reservoirs that are treated before distribution. However, tap water quality can vary by location:

• Melbourne & Sydney : Low TDS (usually under 100 mg/L)
• Brisbane & Perth : Moderate TDS (200-500 mg/L)
• Adelaide & Regional Areas : Higher TDS (often over 500 mg/L due to groundwater sources)

• Bore Water : Often hashigh TDS levelsdue to dissolved salts and minerals from underground sources. In some cases, bore water in Australia can exceed1,200 mg/L, making it unsuitable for drinking without treatment.
• Rainwater : Typically hasvery low TDSbecause it is naturally filtered by evaporation. However, contamination from roofs, pipes, and storage tanks can increase its TDS.

Related: Is Rainwater Safe to Drink in Australia?

• Bottled water usually has a TDS level between50-300 mg/L,depending on the brand and source. Some mineral water brands intentionally have higher TDS due to added minerals.
• Filtered water (e.g., reverse osmosis or carbon filters) usually has lower TDS levels, often below50 mg/L.

Measuring TDS is easy with aTDS meter, which you can buy online or from hardware stores. Simply dip the meter in a glass of water, and it will display theTDS reading in ppm (mg/L).

If your TDS levels are high, you might want to consider water filtration options.

If you want to lower TDS levels in your drinking water, here are some effective methods:

1. Reverse Osmosis (RO) Filters : These systems can remove up to99% of TDS, making them one of the most effective solutions.

2. Distillation : Boiling water and collecting the steam leaves behind dissolved solids, producing very pure water.

3. Deionisation : Uses special resins to remove ions from water, reducing TDS.

4. Carbon Filters : While these improve taste and remove some contaminants, theydon’t significantly reduce TDS.

It’s important to note thatnot all TDS is bad—some minerals in water are beneficial. If you’re using RO or distilled water, you may need toremineralizeit with essential minerals for better taste and health benefits.

For most Australians,TDS in waterisn’t a major concern unless levels are excessively high. If your water has an odd taste, leaves stains, or causes buildup in appliances, it may be worth testing and filtering.

If you live inregional areas or rely on bore water, it’s a good idea to check your TDS levels regularly and consider a filtration system if necessary. Otherwise, for city dwellers with access to treated tap water, TDS is usually within safe and acceptable limits.

By understanding whatTDS in watermeans and how it affects you, you can make informed choices about your drinking water and overall health.