Drinking water quality · 2022
· Verified
· PWSID CA4910012
What's in Sonoma, City of — Sonoma, Ca, CA tap water
Only 8 of 27 core regulated contaminants were reported for Sonoma, City of — Sonoma, Ca, CA. What was measured is clean — but most of the picture is missing.
- !1 open monitoring or reporting violation
- !1 contaminant within 20% of a limit
- !8 of 27 core regulated contaminants reported — 19 never appear in this report
- ✓Nothing over a federal limit
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −0 contaminants at or above a federal limit
- −4 contaminants within 20% of a limit
- −0 open health-based violations
- −3 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −17 core regulated contaminants never reported (8/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- Arsenic85% of the federal limit6.9–8.5 ug/L · limit 10 ug/L
A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
Higher than 95% of CA systems that report it · higher than 90% of U.S. systems
+18 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| HAA5 | 5.96–22.29 ug/L | 60 ug/L |
| TTHM | 24–28 ug/L | 80 ug/L |
| Fluoride | 0.37 mg/L | 4 mg/L |
| Nitrate | 0.35–0.87 mg/L | 10 mg/L |
| Copper | 0.11 mg/L | 1.3 mg/L |
| Bromide | 20–38 ug/L | — |
| Calcium | 15–27 mg/L | — |
| Germanium | 0.43–2.1 ug/L | — |
| Lead | Not detected ug/L | 15 ug/L |
| Magnesium | 4.9–18 mg/L | — |
| Manganese | 28 ug/L | — |
| Sodium | 9.6–37 mg/L | — |
| Chromium | Not detected ug/L | 100 ug/L |
| Bicarbonate | 120–150 mg/L | — |
| Hardness | 56–141 mg/L | — |
| pH | 7.27–7.58 | — |
| TOC | 0–0.78 mg/L | — |
| Gross Alpha | Not detected pCi/L | 15 pCi/L |
What this report doesn't tell you
19 of the 27 contaminants a community water system normally reports do not appear anywhere in Sonoma, City of — Sonoma, Ca, CA's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based1 violation on record · most recent Dec 2009resolved
- Reporting1 violation on record · most recent Jul 20251 open
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗