Arsenic in Sonoma, CA Drinking Water
Arsenic data for Sonoma, California · 13,206 residents · 1 ZIP code
Within Sonoma, California, Arsenic has been detected in water samples drawn from the public supply — the results are part of the official EPA compliance record for systems here.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Arsenic in Sonoma Tap Water
Arsenic has been detected in Sonoma, California drinking water at a maximum level of 6.98 ppb — below the EPA MCL of 10 ppb.
This analysis covers 13,206 residents across 1 ZIP code in Sonoma.
Sonoma's overall water quality grade is B (73/100).
Is Arsenic in Sonoma Water Safe?
Arsenic was detected in Sonoma water but currently falls within EPA limits. However, some health organizations argue the EPA MCL may not be protective enough.
If you are concerned, a reverse osmosis filter can reduce arsenic levels further.
Arsenic Levels by ZIP Code
| ZIP Code | Arsenic Level | EPA Limit | Status |
|---|---|---|---|
| 95476 | 6.98 ppb | 10 ppb | OK |
Average arsenic level across Sonoma: 6.98 ppb
Health Effects of Arsenic
- Increased risk of skin, bladder, lung, and kidney cancer
- Cardiovascular disease and type 2 diabetes
- Skin changes (darkening, thickening, lesions)
- Developmental effects in children exposed in utero
Health risk severity: High. Governed by the Arsenic Rule (2006).
How Arsenic Gets Into Drinking Water
- Natural deposits in rock and soil (especially in western U.S.)
- Runoff from orchards and glass/electronics production
- Historical use of arsenic-based pesticides
- Well water in areas with arsenic-rich geology
What to Do About Arsenic in Sonoma Water
- Install a reverse osmosis (RO) system certified under NSF 58
- Adsorptive media filters (iron-based) can also reduce arsenic
- Have well water tested if on a private supply
- Boiling water does NOT remove arsenic — it concentrates it
Look for filters certified under NSF 53 / NSF 58 for arsenic removal.