Tap WaterIndex

← California

Tap water quality report

Oak Knolls Mutual Water Company

EPA monitoring tested this supplier for 57 contaminants and detected 20. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

57
contaminants tested
20
detected
123
people served
10
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
Ground water
Ownership
Private
Counties served
Kern

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.

10
health-based violations
40
violations on file
2
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2025-01-01 → 2025-03-31
TT Health-based Unaddressed 2024-10-17
MCL Health-based Resolved 2024-10-01 → 2024-12-31
MCL Health-based Resolved 2024-10-01 → 2024-12-31
MCL Health-based Resolved 2024-07-01 → 2024-09-30
MCL Health-based Resolved 2024-07-01 → 2024-09-30
MCL Health-based Archived 2024-04-01 → 2024-06-30
MCL Health-based Archived 2024-01-01 → 2024-03-31
MCL Health-based Resolved 2012-03-01 → 2012-03-31
MCL Health-based Resolved 2012-03-01 → 2012-03-31

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
9000 µg/L 90%
of the EPA limit 10000 µg/L
 54/54 SYR4 2012–2019
Lead
0.00090 mg/L 6%
of the EPA limit 0.0150 mg/L
 13/13 LCR 2025
Barium
68.6 µg/L 3.4%
of the EPA limit 2000 µg/L
worst single sample: 69 µg/L
9/9 SYR4 2013–2019
Combined Uranium
9.5062 µg/L 32%
of the EPA limit 30 µg/L
worst single sample: 9.983 µg/L
9/9 SYR4 2012–2013
Fluoride
560 µg/L 14%
of the EPA limit 4000 µg/L
 9/9 SYR4 2013–2019
Bromodichloromethane
13.55 µg/L
No EPA limit set
worst single sample: 14 µg/L
4/4 SYR4 2015–2018
Bromoform
6.895 µg/L
No EPA limit set
worst single sample: 7.3 µg/L
4/4 SYR4 2015–2018
Chloroform
10.58 µg/L
No EPA limit set
worst single sample: 11 µg/L
4/4 SYR4 2015–2018
Dibromochloromethane
15.4 µg/L
No EPA limit set
worst single sample: 16 µg/L
4/4 SYR4 2015–2018
TTHM
46.75 µg/L 58%
of the EPA limit 80 µg/L
worst single sample: 49 µg/L
4/4 SYR4 2015–2018
Total Haloacetic Acids (HAA5)
8.745 µg/L 15%
of the EPA limit 60 µg/L
worst single sample: 9 µg/L
4/4 SYR4 2015–2018
Dibromoacetic Acid
4.26 µg/L
No EPA limit set
worst single sample: 4.3 µg/L
3/4 SYR4 2015–2018
1,2-DIBROMO-3-CHLOROPROPANE
0.0379 µg/L 19%
of the EPA limit 0.2000 µg/L
worst single sample: 0.0380 µg/L
2/3 SYR4 2016
Arsenic
2.19 µg/L 22%
of the EPA limit 10 µg/L
worst single sample: 2.2 µg/L
2/9 SYR4 2013–2019
Trichloroacetic Acid
2.65 µg/L
No EPA limit set
worst single sample: 2.7 µg/L
2/4 SYR4 2015–2018
Copper
36 µg/L 2.8%
of the EPA limit 1300 µg/L
 1/9 SYR4 2013–2019
Dichloroacetic Acid
3.4 µg/L
No EPA limit set
 1/4 SYR4 2015–2018
Lead
6.2 µg/L 41%
of the EPA limit 15 µg/L
 1/9 SYR4 2013–2019
Monochloroacetic Acid
4.7 µg/L
No EPA limit set
 1/4 SYR4 2015–2018
Selenium
2 µg/L 4%
of the EPA limit 50 µg/L
 1/9 SYR4 2013–2019
37 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-DichloropropaneAntimony, TotalAsbestosAtrazineBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCadmiumCarbon TetrachlorideChromiumDichloromethaneDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateEthylene DibromideEthylbenzeneLassoMercuryMonobromoacetic AcidNitriteSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
TRUBEY, DENNIS
Phone
928-234-0499
Email
dennistrubeypools@aol.com

Frequently asked questions about Oak Knolls Mutual Water Company

Is Oak Knolls Mutual Water Company tap water safe to drink?

EPA monitoring detected 20 contaminants in Oak Knolls Mutual Water Company'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 Oak Knolls Mutual Water Company's water?

EPA monitoring detected Nitrate, Lead, Barium, Combined Uranium, Fluoride, and others. The full list with the level and data source for each is above.

How many people does Oak Knolls Mutual Water Company serve?

Oak Knolls Mutual Water Company reports serving 123 people in California, per its EPA record.

Has Oak Knolls Mutual Water Company had any water quality violations?

The EPA has 40 violations on file for Oak Knolls Mutual Water Company, of which 10 are health-based (a contaminant limit or required treatment was breached) and 2 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.