California · State Water Board SDWIS data

See your local tap-water snapshot in seconds

Enter a California ZIP to match a public water system, review recent detected contaminants, and compare legal limits with California health guidelines — in plain English.

Free · No signup to view · Confirm the utility on your bill · Shareable report

Try: 92501 Riverside 90210 Beverly Hills 94577 East Bay 94550 Livermore (multi) 94102 SF
✓ Based on CA SDWIS public monitoring data ✓ Not medical advice · Not EWG ✓ Free for homeowners
2,429CA ZIPs covered
2,211community systems
Boundary-firstutility matching
2023–2026current extract window

Clear answers from public data

TapCheck CA translates utility-style water quality numbers into plain English — with an optional way to ask a local filtration installer questions.

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ZIP → utility snapshot

See which water system we matched, confidence, and alternatives when service areas overlap. Confirm against your bill.

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Legal limit vs health guideline

EPA MCLs (what's legal) and California PHGs (stricter health guidelines) side by side.

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Filter guidance + local help

Compare carbon vs reverse osmosis educationally, then optionally ask a local installer about options.

Important: Reports use public California State Water Board SDWIS monitoring data (recent community-system detections). ZIP→utility matching prefers official service-area boundaries where available; some ZIPs still use HQ/city estimates, and overlapping areas show a utility chooser. This is not a lab test of your faucet, not medical advice, and not affiliated with EWG or any water utility. Read methodology & disclaimers.

Explore by region

Educational shortcuts into ZIP search — reports still match a specific utility.

Inland Empire Los Angeles Bay Area San Diego Contaminant glossary

Optional: talk with a local installer

If you’d like a licensed filtration installer to explain options for your ZIP, leave your contact info. Someone covering your area may reach out. No obligation — and we don’t show plumber plan pricing on this consumer site.

We do not show plumber plan prices on this consumer site.