Tap Water Contaminants (2026): What’s in Your Water

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The short answer

Tap water contaminants range from lead and arsenic to disinfection byproducts, nitrate, PFAS, and microbes. The EPA sets legal limits on over 90 contaminants in public water, and your utility must send you a water quality report every year by July 1. Private wells aren’t federally regulated, so owners need to test. Once you know what’s in your water, choose a filter certified for those contaminants.

What contaminants are in tap water?

The EPA’s national primary drinking water regulations group them as microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals, and radionuclides, with PFAS in their own section. Common ones, with their federal limits:

Limits from the EPA’s national primary drinking water regulations unless noted. In May 2026 the EPA proposed giving systems until 2031 to meet the PFOA and PFOS limits and rescinding limits for four other PFAS; those are proposals, not final rules (EPA).

Which contaminants aren’t regulated yet?

In April 2026 the EPA’s draft Contaminant Candidate List named microplastics, pharmaceuticals, PFAS, and disinfection byproducts as priority groups, alongside 75 chemicals and nine microbes (EPA). Listing is a step toward possible regulation, not a limit. Hardness and manganese have only non-enforceable guidelines or none. See microplastics, hard water, and manganese.

How do you find out what’s in your tap water?

• City water: read your utility’s Consumer Confidence Report, due each year by July 1. Under revised rules, reports become easier to read starting in 2027, and systems serving over 10,000 people will send them twice a year.
• Private wells: they aren’t regulated by the federal government. The EPA advises testing every year for total coliform bacteria, nitrates, total dissolved solids, and pH.
• Any home: use a state-certified drinking water lab. The EPA can’t test homes on request. Your utility can also tell you whether your service line is lead; the EPA estimates about 4 million lead service lines remain.

Which filter removes the most contaminants?

Certified reverse osmosis covers the widest range: the AquaTru Carafe is certified by IAPMO R&T for lead, fluoride, arsenic, nitrate, PFOA/PFOS, and microplastics. If your report shows only one or two concerns, a cheaper filter certified for those may be enough. Compare picks in the best drinking water filters.

Certified: Certified by an independent body (named in each pick). Lab test: Tested by a named independent lab, not certified. Claim: The maker's claim, not certified. No: No claim. PFAS means PFOA/PFOS, or Total PFAS where the pick says so.

Common questions

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