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Tap water quality report

Sierra Twain Harte Mhp

EPA monitoring tested this supplier for 53 contaminants and detected 10. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

53
contaminants tested
10
detected
129
people served
4
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
Ground water
Ownership
Private
Counties served
Tuolumne

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.

4
health-based violations
13
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 1999-10-01 → 1999-10-31
MCL Health-based Resolved 1999-10-01 → 1999-10-31
MCL Health-based Resolved 1999-10-01 → 1999-10-31
MCL Health-based Resolved 1999-10-01 → 1999-10-31
MON Monitoring Resolved 2025-04-01 → 2025-04-30
MON Monitoring Resolved 2025-04-01 → 2025-04-30
MR Monitoring Resolved 2015-08-01 → 2015-08-31
MR Monitoring Resolved 2015-08-01 → 2015-08-31
MR Monitoring Resolved 1993-07-01 → 2003-12-31
Other Monitoring Archived 1983-06-01 → 1983-06-30

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
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 7/7 LCR 2024
Fluoride
193.1 µg/L 4.8%
of the EPA limit 4000 µg/L
worst single sample: 199 µg/L
3/4 SYR4 2013–2019
TTHM
1.727 µg/L 2.2%
of the EPA limit 80 µg/L
worst single sample: 1.76 µg/L
3/3 SYR4 2014–2018
Chloroform
1.7385 µg/L
No EPA limit set
worst single sample: 1.76 µg/L
2/3 SYR4 2014–2018
Dibromoacetic Acid
2.514 µg/L
No EPA limit set
worst single sample: 2.59 µg/L
2/3 SYR4 2014–2018
Dichloroacetic Acid
1.674 µg/L
No EPA limit set
worst single sample: 1.68 µg/L
2/3 SYR4 2014–2018
Total Haloacetic Acids (HAA5)
5.4515 µg/L 9.1%
of the EPA limit 60 µg/L
worst single sample: 5.6 µg/L
2/3 SYR4 2014–2018
Arsenic
3.79 µg/L 38%
of the EPA limit 10 µg/L
 1/4 SYR4 2013–2019
Dichloromethane
8.39 µg/L 168%
of the EPA limit, at the 95th percentile of samples — 5 µg/L
 1/2 SYR4 2017–2018
Monobromoacetic Acid
1.33 µg/L
No EPA limit set
 1/3 SYR4 2014–2018
43 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-DichloropropaneAntimony, TotalAtrazineBariumBenzeneBeryllium, TotalBromodichloromethaneBromoformChlorobenzeneCopperCadmiumCarbon TetrachlorideChromiumDibromochloromethaneEthylene DibromideEthylbenzeneLassoLeadMercuryMonochloroacetic AcidNitrateNitrate-NitriteNitriteSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTrichloroacetic AcidTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
BARTELS, OLIVIA
Phone
209-630-8876
Email
Properties@moyleexcavation.com

Frequently asked questions about Sierra Twain Harte Mhp

Is Sierra Twain Harte Mhp tap water safe to drink?

EPA monitoring detected 10 contaminants in Sierra Twain Harte Mhp'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 Sierra Twain Harte Mhp's water?

EPA monitoring detected Lead, Fluoride, TTHM, Chloroform, Dibromoacetic Acid, and others. The full list with the level and data source for each is above.

How many people does Sierra Twain Harte Mhp serve?

Sierra Twain Harte Mhp reports serving 129 people in California, per its EPA record.

Has Sierra Twain Harte Mhp had any water quality violations?

The EPA has 13 violations on file for Sierra Twain Harte Mhp, of which 4 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.