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Atascadero Mutual Water Co

EPA monitoring tested this supplier for 84 contaminants and detected 26. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

84
contaminants tested
26
detected
30,618
people served
2
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
Ground water
Ownership
Private
Counties served
San Luis Obispo

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

2
health-based violations
2
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 1993-06-01 → 1993-06-30
TT Health-based Resolved 1993-06-01 → 1993-06-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
PFHXS 0.0076 µg/L 6/8 2023
PFBS 0.0094 µg/L 4/8 2023
PFOS 0.0223 µg/L 4/8 2023
Pfba 0.0100 µg/L 2/8 2023
PFOA 0.0084 µg/L 2/8 2023

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Nitrate
2938 µg/L 29%
of the EPA limit 10000 µg/L
worst single sample: 4600 µg/L
608/726 SYR4 2012–2019
Dibromoacetic Acid
8.6 µg/L
No EPA limit set
worst single sample: 9.7 µg/L
181/181 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
19.1 µg/L 32%
of the EPA limit 60 µg/L
worst single sample: 27.2 µg/L
181/181 SYR4 2012–2019
Bromodichloromethane
18.9 µg/L
No EPA limit set
worst single sample: 25 µg/L
175/181 SYR4 2012–2019
Bromoform
8.25 µg/L
No EPA limit set
worst single sample: 10.1 µg/L
175/181 SYR4 2012–2019
Chloroform
15.51 µg/L
No EPA limit set
worst single sample: 22.8 µg/L
175/181 SYR4 2012–2019
TTHM
60.85 µg/L 76%
of the EPA limit 80 µg/L
worst single sample: 68.8 µg/L
175/181 SYR4 2012–2019
Dichloroacetic Acid
9.365 µg/L
No EPA limit set
worst single sample: 12.6 µg/L
170/170 SYR4 2012–2019
Dibromochloromethane
20.26 µg/L
No EPA limit set
worst single sample: 24.3 µg/L
169/176 SYR4 2012–2019
Trichloroacetic Acid
3.85 µg/L
No EPA limit set
worst single sample: 4.7 µg/L
111/122 SYR4 2012–2019
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 69/69 LCR 2025
Fluoride
331.5 µg/L 8.3%
of the EPA limit 4000 µg/L
worst single sample: 360 µg/L
58/62 SYR4 2012–2019
Nitrate-Nitrite
671000 µg/L 6710%
of the EPA limit, at the 95th percentile of samples — 10000 µg/L
worst single sample: 860000 µg/L
30/38 SYR4 2013–2019
Combined Uranium
16.688 µg/L 56%
of the EPA limit 30 µg/L
worst single sample: 19.37 µg/L
19/21 SYR4 2012–2019
Selenium
9.48 µg/L 19%
of the EPA limit 50 µg/L
worst single sample: 10 µg/L
14/51 SYR4 2012–2019
Lithium
20.7 µg/L
No EPA limit set
 6/8 UCMR-5 2023
Barium
130 µg/L 6.5%
of the EPA limit 2000 µg/L
 5/51 SYR4 2012–2019
Arsenic
3.28 µg/L 33%
of the EPA limit 10 µg/L
worst single sample: 3.4 µg/L
4/51 SYR4 2012–2019
Cadmium
2.51 µg/L 50%
of the EPA limit 5 µg/L
worst single sample: 2.6 µg/L
3/51 SYR4 2012–2019
Monobromoacetic Acid
1 µg/L
No EPA limit set
 3/33 SYR4 2012–2019
Monochloroacetic Acid
2.68 µg/L
No EPA limit set
worst single sample: 2.7 µg/L
2/32 SYR4 2012–2019
58 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBenzeneBeryllium, TotalChlorobenzeneCopperCyanideCarbon TetrachlorideChromiumDichloromethaneEthylbenzeneGlyphosateHfpo-DaLassoLeadMercuryNetfosaaNfdhaNmefosaaNitritePfdaPfdoaPfeesaPfhpaPfhpsPfhxaPfmbaPfmpaPFNAPfpeaPfpesPftaPftrdaPfunaSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
POWERS, CHERYL
Phone
805-400-5851
Email
[email protected]

Frequently asked questions about Atascadero Mutual Water Co

Is Atascadero Mutual Water Co tap water safe to drink?

EPA monitoring detected 26 contaminants in Atascadero Mutual Water Co's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Atascadero Mutual Water Co's water?

EPA monitoring detected Nitrate, Dibromoacetic Acid, Total Haloacetic Acids (HAA5), Bromodichloromethane, Bromoform, and others. The full list with the level and data source for each is above.

How many people does Atascadero Mutual Water Co serve?

Atascadero Mutual Water Co reports serving 30,618 people in California, per its EPA record.

Has Atascadero Mutual Water Co had any water quality violations?

The EPA has 2 violations on file for Atascadero Mutual Water Co, of which 2 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.