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Tap water quality report

Mission Highlands Mutual Water Co.

EPA monitoring tested this supplier for 62 contaminants and detected 11. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

62
contaminants tested
11
detected
150
people served
2
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
Ground water
Ownership
Private
Counties served
Sonoma

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
16
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2001-07-01 → 2001-07-31
MCL Health-based Resolved 2001-07-01 → 2001-07-31
MON Monitoring Resolved 2021-05-01 → 2021-05-31
MON Monitoring Resolved 2021-05-01 → 2021-05-31
MR Monitoring Resolved 2019-10-01
MR Monitoring Resolved 2019-10-01
MR Monitoring Resolved 2019-10-01
MR Monitoring Resolved 2019-01-01 → 2021-12-31
MR Monitoring Resolved 2019-01-01 → 2021-12-31
MR Monitoring Resolved 2019-01-01 → 2021-12-31

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 single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Nitrate
1401.2 µg/L 14%
of the EPA limit 10000 µg/L
 78/78 SYR4 2012–2019
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 26/26 LCR 2023
Arsenic
5.7 µg/L 57%
of the EPA limit 10 µg/L
 6/6 SYR4 2014–2017
Dibromochloromethane
3.6 µg/L
No EPA limit set
 4/4 SYR4 2013–2018
TTHM
14 µg/L 18%
of the EPA limit 80 µg/L
 4/4 SYR4 2013–2018
Bromodichloromethane
4 µg/L
No EPA limit set
 3/4 SYR4 2013–2018
Chloroform
2.5 µg/L
No EPA limit set
 2/4 SYR4 2013–2018
Dibromoacetic Acid
3.36 µg/L
No EPA limit set
 2/4 SYR4 2013–2018
Fluoride
170 µg/L 4.3%
of the EPA limit 4000 µg/L
 2/3 SYR4 2017
Total Haloacetic Acids (HAA5)
3.36 µg/L 5.6%
of the EPA limit 60 µg/L
 2/4 SYR4 2013–2018
Bromoform
1 µg/L
No EPA limit set
 1/4 SYR4 2013–2018
51 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAsbestosAtrazineBhc-GammaBenzeneChlorobenzeneCopperCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDichloroacetic AcidDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNitriteOxamylPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneTolueneToxapheneTrichloroacetic AcidTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
JOHNSTON, TOPPER
Phone
415-710-8629
Email
p39topper@gmail.com

Frequently asked questions about Mission Highlands Mutual Water Co.

Is Mission Highlands Mutual Water Co. tap water safe to drink?

EPA monitoring detected 11 contaminants in Mission Highlands 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 Mission Highlands Mutual Water Co.'s water?

EPA monitoring detected Nitrate, Lead, Arsenic, Dibromochloromethane, TTHM, and others. The full list with the level and data source for each is above.

How many people does Mission Highlands Mutual Water Co. serve?

Mission Highlands Mutual Water Co. reports serving 150 people in California, per its EPA record.

Has Mission Highlands Mutual Water Co. had any water quality violations?

The EPA has 16 violations on file for Mission Highlands 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.