Arsenic in Maple Valley, WA Drinking Water
Arsenic data for Maple Valley, Washington · 29,097 residents · 1 ZIP code
Within Maple Valley, Washington, 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 Maple Valley Tap Water
Arsenic has been detected in Maple Valley, Washington drinking water at a maximum level of 400 ppb — 40x the EPA MCL.
This analysis covers 29,097 residents across 1 ZIP code in Maple Valley.
Maple Valley's overall water quality grade is B (78/100).
Is Arsenic in Maple Valley Water Safe?
If you live in an affected ZIP code, consider installing a reverse osmosis filter certified under NSF 53 / NSF 58 and testing your water independently.
Arsenic Levels by ZIP Code
| ZIP Code | Arsenic Level | EPA Limit | Status |
|---|---|---|---|
| 98038 | 400 ppb | 10 ppb | Exceeds limit |
Average arsenic level across Maple Valley: 400 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 Maple Valley 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.