Arsenic in Lancaster, CA Drinking Water
Arsenic data for Lancaster, California · 194,781 residents · 6 ZIP codes
Across the water systems that serve Lancaster, California, Arsenic has appeared in EPA compliance samples — standard municipal treatment targets this contaminant, though detections in the compliance record indicate it has reached household taps at measurable levels.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-04-05
Arsenic in Lancaster Tap Water
Lancaster, California has 84 EPA violations related to arsenic in drinking water.
This analysis covers 194,781 residents across 6 ZIP codes in Lancaster.
Lancaster's overall water quality grade is D (40/100).
Is Arsenic in Lancaster 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.
EPA Violations for Arsenic in Lancaster
| Date | Violation Type | Status | ZIP Code |
|---|---|---|---|
| 2025-04-01 | Arsenic (Known) | Known | 93534 |
| 2025-04-01 | Arsenic (Known) | Known | 93535 |
| 2025-04-01 | Arsenic (Known) | Known | 93536 |
| 2025-04-01 | Arsenic (Known) | Known | 93539 |
| 2025-04-01 | Arsenic (Known) | Known | 93584 |
| 2025-04-01 | Arsenic (Known) | Known | 93586 |
| 2025-01-01 | Arsenic (Known) | Known | 93534 |
| 2025-01-01 | Arsenic (Known) | Known | 93535 |
| 2025-01-01 | Arsenic (Known) | Known | 93536 |
| 2025-01-01 | Arsenic (Known) | Known | 93539 |
| 2025-01-01 | Arsenic (Known) | Known | 93584 |
| 2025-01-01 | Arsenic (Known) | Known | 93586 |
| 2024-10-01 | Arsenic (Known) | Known | 93534 |
| 2024-10-01 | Arsenic (Known) | Known | 93535 |
| 2024-10-01 | Arsenic (Known) | Known | 93536 |
| 2024-10-01 | Arsenic (Known) | Known | 93539 |
| 2024-10-01 | Arsenic (Known) | Known | 93584 |
| 2024-10-01 | Arsenic (Known) | Known | 93586 |
| 2024-07-01 | Arsenic (Known) | Known | 93534 |
| 2024-07-01 | Arsenic (Known) | Known | 93535 |
| ... | 64 more violations |
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 Lancaster 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.