How to Check Ppm of Water

Co-authored by Brian Blake

Last Updated: January 3, 2025

If your water is odorless and clear, how in the world can you tell what’s in it? The answer is you measure really, really small. Parts per million (ppm) measures tiny amounts of substances in your water. It’s actually really easy to test the ppm of water to make sure it’s safe to drink. You just need a water quality tester. To help you out, we’ve answered a few of the most common questions about testing the ppm of water.

Question 1 of 5:

What is ppm water testing?

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Ppm water testing measures substances in the water. Parts per million (ppm) equals one part contaminant to one million parts water. Ppm testing is an effective way to measure substances like chlorine and salt. For reference, 1 ppm is the equivalent of 1 or 2 grains of sugar dissolved in a bathtub full of water.^{[1]
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- Some substances and toxins are so small they can be measured in parts per billion (ppb).

Question 2 of 5:

Is ppm and TDS the same?

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TDS stands for total dissolved solids, which are the amount of organic and inorganic substances in the water. It can include salts, metals, minerals, and other substances.^{[2]
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Research source} TDS uses parts per million (ppm) as a measurement of solids contained within a volume of water. So essentially, TDS and ppm are components of each other.

Question 3 of 5:

How do you measure ppm in water?

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1
Use a water quality tester to quickly test the water. A water quality tester is an electronic device that quickly tests the ppm of a sample of water. Fill a glass with water, turn on the tester, and insert it into the water. Wait a minute or so until the tester takes a reading and then check the ppm of the water sample.^{[3]
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- You can find water quality testers at pool supply stores. You can also order them online.
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Use a color-wheel test for a simple chlorine test. A color-wheel test is commonly used to test pool water to check the chlorine levels. You’ll dissolve a special tablet in a sample of the water that causes it to change colors. Then, you’ll compare the color of the water to a chart to get a range of the ppm levels of chlorine in the water.
- A digital colorimeter involves dissolving special tablets into a sample of water that causes the water to change colors, which you can then test with a special meter. It’s more accurate than a color-wheel test.

Question 4 of 5:

What is the normal ppm of tap water?

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Because tap water is often used as drinking water and for tasks such as washing dishes and bathing, you want the ppm levels to be low. The lower the ppm, the lower the amount of total dissolved solids (TDS) in the water such as inorganic salts and minerals like calcium, magnesium, and potassium. Anything below 100 ppm is a good range.

Question 5 of 5:

How many ppm in water is safe?

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While the ideal range for drinking water is below 100 ppm, water is still safe at higher levels. Any water with a ppm level below 400 ppm is safe for things like bathing, washing, and even drinking.