B68/100
ATASCADERO MUTUAL WATER CO — Water Quality Report 2026
Serving 30,618 people · California
Water Source
Groundwater
County
—
System ID
CA4010002
Violations
1
Contaminant Test Results
4 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.50 mg/L | 1.30 mg/L | Over Limit |
PFOS | 0.022 µg/L | 0.004 µg/L | Over Limit |
PFOA | 0.007 µg/L | 0.004 µg/L | Over Limit |
chlorate | 410.00 µg/L | — | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 1993.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About ATASCADERO MUTUAL WATER CO
Is ATASCADERO MUTUAL WATER CO water safe to drink?
ATASCADERO MUTUAL WATER CO water receives a grade of B (68/100), which is considered good. Out of 67 contaminants tested, 3 exceed EPA legal limits. 4 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has ATASCADERO MUTUAL WATER CO detected?
67 contaminants were tested in ATASCADERO MUTUAL WATER CO's water. Notable contaminants include PFOS, PFOA, Copper (90th percentile), chlorate. 3 exceed EPA legal limits (MCLs). 4 exceed EPA health goals (MCLGs).
Does ATASCADERO MUTUAL WATER CO have any EPA violations?
Yes, ATASCADERO MUTUAL WATER CO has 1 EPA violation(s) on record, with the most recent in 1993. Violation types include TT. 1 are health-based violations.
How many people does ATASCADERO MUTUAL WATER CO serve?
ATASCADERO MUTUAL WATER CO serves approximately 30,618 people, California.
What type of water does ATASCADERO MUTUAL WATER CO provide?
ATASCADERO MUTUAL WATER CO sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is CA4010002.
How does ATASCADERO MUTUAL WATER CO compare to other utilities in California?
ATASCADERO MUTUAL WATER CO scores 68/100 with a grade of B (good). This is an above-average performance for utilities statewide. Visit our California state page for a full comparison of water systems.