Water Testing and Contaminants: Complete Guide

Everything else on this site depends on knowing what is in your water. Testing is cheap relative to the equipment it prevents you buying by mistake, and it is the only way to specify treatment properly.

What this section covers

  • Hardness testing and the difference between grains per gallon and parts per million
  • Total dissolved solids and what a TDS meter can and cannot tell you
  • Certified laboratory panels versus home test strips
  • Reading a municipal Consumer Confidence Report
  • Lead, PFAS, nitrates, arsenic, manganese, chlorine and chloramine
  • NSF/ANSI 42, 44, 53, 58 and 401 explained in plain English

Municipal supply or private well?

If you are on a municipal supply, your utility publishes an annual Consumer Confidence Report showing what was detected and at what level. That report is free, specific to your system, and the correct starting point. It will not tell you what happened to the water between the treatment plant and your tap, which is why lead testing at the tap is still worthwhile in older housing.

If you are on a private well, nobody is testing for you. See Well Water.

Test strips versus laboratory panels

Strips are useful for one job: getting a rough hardness or chlorine number quickly so you can size equipment. They are not reliable for health-related contaminants. Where the question is lead, nitrate, arsenic, bacteria or PFAS, a certified laboratory panel with a chain of custody is the only sensible answer.

Important

Water Upkeep reports regulatory limits and certification facts. We do not interpret results medically and we do not advise on health risk. If a result exceeds an EPA maximum contaminant level, contact your state or local health department.

Common questions

What does a TDS meter actually measure?

The total concentration of dissolved solids, expressed in parts per million. It is a useful way to check whether a reverse osmosis membrane is still working. It tells you nothing about which solids are present, so it cannot detect lead, bacteria or PFAS.

How do I convert hardness units?

One grain per gallon is approximately 17.1 parts per million as calcium carbonate. Laboratories usually report ppm; softener sizing usually uses gpg.

How much does a proper water test cost?

Basic mail-in panels covering the common well parameters typically run from around one hundred dollars; broader panels including metals and PFAS cost several times that. Many county health departments offer low-cost bacteria testing.

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Last reviewed September 6, 2026.