User Guide

Perhaps the water purification system was faulty, or something had contaminated the distilled
water. TDS testing is like a watchdog. It will tell you if things are not as they should be. Let’s
take a look at all the ways you can use a TDS meter to check water quality.
TDS and tap water
Tap water contains a variety of minerals and salts like calcium, magnesium, chloride, and
potassium. The more minerals and salts in the water, the higher the TDS. The United States
Environmental Protection Agency sets the standards for drinking water in the US. For
aesthetics, the recommended maximum TDS in drinking water is 500 ppm. A high TDS usually
indicates that the water source contains a high level of minerals, carbonates, and other salts.
This water is probably corrosive to plumbing fixtures, pipes, and appliances. The water may
taste bad too, due to the high mineral content. However, a high TDS does not necessarily mean
that the water is a health hazard.
What TDS level is normal?
“Normal” TDS levels are relative to the type of water being tested. Reverse osmosis water
should have a low TDS, and mineral spring water normally has a higher TDS level. We’ve
created the following TDS reference chart to help explain this concept.