How to measure water quality? PPM vs. TDS value: What do the values reveal about my drinking water?

You often read that you can use the TDS reading to assess the quality of water . This suggests that the TDS value says something about whether your drinking water is free of pesticides, medication and other substances that are harmful to health. This is a big misunderstanding , because the TDS value is a purely quantitative value for the amount of substances that are dissolved in drinking water, for example. But it does not allow any conclusions to be drawn about which substances are involved.
That is why you will learn in this Guidebook , that...

• a low TDS value ( ≤ 100 ppm) says nothing about good water quality.
• a TDS analysis only measures the amount of salts, minerals and metals.
• the sum of these dissolved particles is given in ppm (parts per million).
• the TDS value does not allow any conclusions to be drawn as to whether there are residues of hormones, pesticides, fungicides, medicines or other substances in the water.
• properly filtered water should be free of toxins, but may contain valuable minerals and trace elements (= high TDS value).

Here we show you how a TDS meter works in practice and how you can correctly interpret the measured values in ppm.

What is the TDS value? Can it measure water quality?

If you want to measure the quality of your drinking water, you may be on the wrong track with a TDS meter. This is due to the nature of the test itself: The TDS value provides information about the amount of substances in your drinking water that have an electrical conductivity - i.e. minerals, salts and metals. Substances such as calcium, magnesium and iron are anything but harmful to the human organism. Heavy metal residues, on the other hand, are. TDS stands for "Total Dissolved Solids". This means that the TDS value indicates the sum or quantity of dissolved solids in the water.

How to measure water quality correctly?

The TDS value therefore does not allow any conclusions to be drawn about the type of substances. A high TDS value (≥ 400 ppm) only indicates that there is an above-average amount of minerals, salts or metals in the drinking water. TDS is therefore a purely quantitative measure of the number of substances dissolved in a water sample. A TDS meter cannot provide any information on whether these substances are beneficial or harmful to health.

How high can the PPM value be? [EU & WHO guidelines]

As the following table shows: Not only the average values measured in German mineral water and Tapwater, but also the officially defined limit values of the EU, the USA and the WHO often cause more confusion than clarity.

If you come across the assertion that only water with a very low TDS value (≤ 100 ppm) is beneficial to health, this is not correct. It is not the quantity of the substance that matters - high calcium or magnesium values are actually desirable in mineral water - but the type of substance. Even the smallest amounts of heavy metals (e.g. copper or lead) can be extremely harmful.

An osmosis filter? The way to healthy water?

As you can see from the table above, an osmosis filter reduces the ppm value in the water to a minimum. After the filtering process, very low TDS values between 0.1 ppm and 25 ppm are not unusual. But does this also mean that my water is healthier after filtration than before? yes and no! This would only be the case if the assumption that only a low TDS value indicates healthy water were correct. To understand this better, we need to look at exactly how an osmosis filter works: If the water whose quality you want to improve is passed through an osmosis filter, the proportion of electrical substances is reduced and the TDS value is low. Osmosis water therefore contains little or no minerals or salts. If some salt were added to the water, the TDS value would increase immediately. However, this would in no way make the water unhealthy. Conversely, for the reasons mentioned, it has not been proven at all that the water with the low TDS value measured after purification is healthier.

The significance of the TDS value for water quality

If you have now measured either a µS value or a ppm value, you have a quantitative result in your hand. You now know that you have a high or low number of conductive, dissolved substances in the water. These can be minerals that shape the regional character of the water. Minerals belong in natural spring water and form its typical regional taste. Whether a water has many or few minerals depends solely on the region and is not a general characteristic of its quality. In fact, the TDS value alone makes no statement about the purity and water quality, as many harmful and unhealthy substances cannot be detected in the physical measurement.

A water filter cannot measure water quality, but it can improve it

If you really want to measure the quality of the water coming out of your tap, there is no getting around a chemical analysis. Only if you have the water quality tested in a laboratory will you receive a well-founded report on which substances are actually in your Tapwater .

After all, all drinking water filters from Albfilter have one thing in common: all water filters from Albfilter ensure clean and high-quality drinking water - free from toxins, but with valuable minerals and trace elements. This means that you can actually influence the water quality instead of just determining a measured value (TDS value), which does not provide any real information about the quality of your water.

FAQs - Important questions briefly explained

What is measured with a TDS meter?

TDS stands for "Total Dissolved Solids". This means that the TDS value indicates the sum of the dissolved solids in the water. These include, for example, minerals, salts and metals. The device used for this purpose performs a physical measurement. It determines the electrical conductivity of the water. The degree of this conductivity depends on the ions, the electrically charged molecules, in the water. Salts, minerals and metals are particularly conductive. The sum of these dissolved particles is given in ppm (parts per million), among other things.

Why does the ppm value say nothing about the quality of water?

The TDS value (in ppm) only provides information about the quantity of substances in your drinking water that have an electrical conductivity - e.g. minerals, salts, metals. When talking about water quality, it is not the quantity but the type of substance that matters. High calcium or magnesium values, which then lead to a high ppm value, are not exactly undesirable in drinking water.

How can water quality be measured independently?

Unfortunately, there are no quick tests for private use. If you want to know what substance concentrations and ingredients are really in your drinking water at home, you can only measure this independently if you have a laboratory test carried out.

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