B73/100
Atascadero Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 34,718 residents · California
What's In Atascadero's Tap Water?
67
Contaminants Tested
3
Exceed EPA Limits
1
Above EPA Goals
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
Water Utility Details
ATASCADERO MUTUAL WATER CO
Population Served
30,618
Water Source
Groundwater
System ID
CA4010002
ATASCADERO STATE HOSPITAL
Population Served
4,100
Water Source
Groundwater
System ID
CA4010832
Frequently Asked Questions About Atascadero Water
Is Atascadero tap water safe to drink?
Atascadero, California tap water receives a grade of B (73/100), which is considered good. Out of 67 contaminants tested, 3 exceed EPA maximum contaminant levels (MCLs) and 5 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Atascadero's water?
Of the 67 contaminants tested in Atascadero's water supply, the most notable include PFOS, PFOA, Copper (90th percentile), Lead (90th percentile), chlorate. 3 contaminant(s) exceed EPA legal limits (MCLs). 5 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Atascadero have any water quality violations?
Yes, Atascadero has 4 EPA violation(s) on record, with the most recent in 2023. Violation types include MR, TT. 1 of these are health-based violations, which are the most serious category.
Do I need a water filter in Atascadero?
Based on EPA data, using a water filter in Atascadero is recommended. 3 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Atascadero's tap water come from?
Atascadero's drinking water is sourced from groundwater and supplied by ATASCADERO MUTUAL WATER CO and 1 other water system(s). The system serves approximately 34,718 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Atascadero's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Atascadero's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Atascadero's water compare to other cities in California?
Atascadero's water quality score of 73/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our California state page to see how all cities in the state compare.
What should I do if I'm concerned about Atascadero's water quality?
If you have concerns about Atascadero's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (ATASCADERO MUTUAL WATER CO) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.