Is your tap water safe? The honest answer is in your utility’s own federal record. In EPA UCMR5 occurrence data, Feb 2026 release (~95% complete; final reporting 2026), 1,693 of 10,299 US public water systems (16.4%, about 1 in 6) reported PFOA or PFOS above the 4-ppt federal limits — which also means about five in six reported under them. This is a check-yours question, not a panic question: enter your ZIP below to see your utility’s actual reported results, graded against the EPA limits and dated.
Try: 07102 Newark45202 Cincinnati48503 Flint28401 Wilmington
ALAMEDA COUNTY WATER DISTRICT
Worth a look
Within current limits, but there is something to be aware of -- see the details.
Matched with high confidence (100%). Confirm it is the system on your water bill.
Every regulated PFAS was non-detect in UCMR5 testing, but this system has health-based violations on record -- see below.
Per EPA UCMR5 (2023-2025), Feb 2026 release: ALAMEDA COUNTY WATER DISTRICT, CA (PWSID CA0110001) -- Worth a look. Within current limits, but there is something to be aware of -- see the details. These are system-level EPA records, not a reading of any individual tap; confirm against the utility's current Consumer Confidence Report.
| PFAS (regulated) | Your utility | EPA limit | Status |
|---|---|---|---|
| PFOA | non-detect (< ~4 ppt) | 4 ppt | Non-detect |
| PFOS | non-detect (< ~4 ppt) | 4 ppt | Non-detect |
| PFHxS | non-detect (< ~3 ppt) | 10 ppt (under reconsideration 2026) | Non-detect |
| PFNA | non-detect (< ~4 ppt) | 10 ppt (under reconsideration 2026) | Non-detect |
| GenX (HFPO-DA) | non-detect (< ~5 ppt) | 10 ppt (under reconsideration 2026) | Non-detect |
| Lead & Copper (90th pct) | Your utility | Action level | Status |
|---|---|---|---|
| Lead (90th percentile) | non-detect (below the reporting limit) (12/31/2024) | 15 ppb | Non-detect |
| Copper (90th percentile) | 1.8 ppm (12/31/1992) | 1.3 ppm | Above action level |
This is the SYSTEM's 90th-percentile result for a monitoring round -- a sampling statistic, not your tap's level. The only way to know YOUR tap is a tap-specific test.
| Other regulated contaminants | Your utility (max) | EPA limit | Status |
|---|---|---|---|
| nitrate | 2.82 mg/L (2023-01-30) | 10 mg/L | Below |
| nitrate + nitrite | 2.82 mg/L (2023-01-30) | 10 mg/L | Below |
| arsenic | 5.6 ug/L (2024-10-30) | 10 ug/L | Below |
| TTHM (total trihalomethanes) | 84 ug/L (2025-10-28) | 80 ug/L | Above limit |
| HAA5 (haloacetic acids) | 46 ug/L (2026-04-14) | 60 ug/L | Below |
| gross alpha | 4.01 pCi/L (2024-02-26) | 15 pCi/L | Below |
| fluoride | 0.83 mg/L (2025-01-08) | 4 mg/L | Below |
Also tested, non-detect: nitrite, uranium, combined radium.
These are measured sample results reported by the water system to its state, by analyte and date -- a system-level record, not a reading of your tap. A single result near or over a limit is a reason to look closer and check the utility's current Consumer Confidence Report, not a verdict on your water.
This is the highest result the system reported (state record), not your tap and not a compliance determination -- and the MCL for this contaminant is a running annual average, so a single high sample is not a violation. Confirm against the utility's current CCR.
EPA violations: 9 drinking-water violation(s) on record: 4 health-based (a contaminant or treatment standard) and 5 monitoring/reporting (paperwork/testing-timing).
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Catches: Copper
UCMR5 results are grab samples; EPA states they do not indicate compliance with the MCLs.
Source: EPA UCMR5 (2023-2025), Feb 2026 release. Lead/copper and violations: EPA SDWIS/ECHO; state contaminant layers where covered. Graded against EPA health-based limits (limit + basis + as-of). Public-domain federal data; this report is a dated snapshot -- your utility's current Consumer Confidence Report is the official local record.
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Frequently asked questions
Is my tap water safe to drink based on my ZIP code?
A ZIP code can tell you which public water system serves you, and that system’s own EPA-reported testing is the honest starting point. The report above shows your utility’s actual reported PFAS, lead and copper, and other regulated-contaminant results, graded against the federal limits and dated. Two cautions we state on every report: these are system-level records, not a reading of your individual tap, and a ZIP can be served by more than one system — confirm the utility on your water bill and its current Consumer Confidence Report (CCR).
How do I check my water quality by ZIP code?
Enter your 5-digit ZIP in the tool above. It resolves your public water system and shows that system’s reported results from the EPA’s UCMR5 PFAS monitoring (2023-2025), lead and copper 90th-percentile results and violations from EPA SDWIS/ECHO, and state-reported contaminants where your state publishes them. Every value is shown with its date and the EPA limit it is graded against. It is free, with no signup.
What does ‘reported above the EPA limit’ mean?
It means at least one reported monitoring result exceeded the limit — a flag worth knowing about, not a violation finding. The EPA’s PFOA/PFOS limit is a running annual average, and the EPA states that UCMR5 grab samples do not indicate compliance on their own. Compliance with the 4-ppt PFAS limits is not required until April 2029 (proposed extension to April 2031), so no utility is out of compliance on that line today. We say ‘reported above the limit’, never ‘in violation’, and we never make health claims from a monitoring number.
Does this cover private wells?
No. EPA monitoring programs and utility reports cover public water systems only. If you are on a private well, no database can tell you what is in your water — a certified lab test of your own tap is the only real answer.
Where does the data come from?
Public-domain federal and state records: the EPA’s UCMR5 PFAS occurrence data (2023-2025), EPA SDWIS/ECHO for lead/copper and violations, and state Drinking Water Watch records where states publish them. Every report states its sources and dates, and our national analyses of the same data are published as reproducible data studies you can check.