Municipal treatment handles bacteria and sediment. It was never designed to catch everything else that ends up in your tap water.
PFAS “forever chemicals”
Synthetic compounds that don’t break down — found in 45% of US tap water samples. No taste, no smell. Read our PFAS explainer.
Lead
Enters water after treatment, through aging service lines and household plumbing — which means your utility’s report can look clean while your tap doesn’t.
Chlorine & disinfection byproducts
Added intentionally to keep water safe in transit — but it affects taste and odor, and its byproducts are regulated contaminants in their own right.
Nitrates
From fertilizer runoff and septic systems; a particular concern for infants and in agricultural areas — and standard carbon filters don’t remove them.
Hardness minerals
Calcium and magnesium aren’t a health risk, but they scale up appliances, water heaters, and fixtures — softening is a separate treatment from filtration.
Sediment & microbial risk
More common on private wells, where no utility stands between the source and your tap — testing establishes the baseline.
How to know what applies to your home
Your utility publishes an annual water quality report — our guide to reading your water report explains it. Or skip the homework: we’ll pull your local data and summarize it for free.
Get the actual data for your address
Free water analysis from EPA and EWG records — a straight answer about what’s in your water.
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