Public water system · CA5510005
ActiveTwain Harte Community Services District
At a glance
Twain Harte Community Services District (PWSID CA5510005) is an active community water system in Tuolumne County, California. It reports serving 2,378 people through 1,588 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in April 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,378
Service connections
1,588
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Twain Harte Community Services District compare with other water systems in Tuolumne County?
By EPA's size categories, Twain Harte Community Services District is a small system (501 to 3,300 people). Tuolumne County has 117 active public water systems. Its population served is about 3.4 times the county average of 706 people per system, and accounts for 2.9% of the 82,611 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so Twain Harte Community Services District is about 65% below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 609 California systems (8.1%) list surface water as their primary source.
Who owns and regulates Twain Harte Community Services District?
EPA lists Twain Harte Community Services District as owned by a local government. The CA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 17 of the 117 active systems in Tuolumne County (15%) are also owned by a local government.
Does Twain Harte Community Services District have drinking water violations?
EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in April 2025. The violations listed here began between July 1980 and April 2025. By type: 2 required treatment not met, 1 monitoring and 1 public notice, recordkeeping or other. The contaminants or rules involved are Revised Total Coliform Rule, Carbon, total and Surface Water Treatment Rule. EPA lists 3 as resolved and 1 as archived. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-04-01 | MonitoringMonitoring, Lab Certification/Method Error (RTCR) · code 3D | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2004-07-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | Resolved |
| 1995-03-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1980-07-28 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
All 4 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Twain Harte Community Services District: frequently asked questions
Who runs Twain Harte Community Services District?
Twain Harte Community Services District (PWSID CA5510005) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Twain Harte Community Services District serve?
Twain Harte Community Services District reports serving 2,378 people through 1,588 service connections in Tuolumne County, California.
Where does Twain Harte Community Services District get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Twain Harte Community Services District have any drinking water violations?
EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in April 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Twain Harte Community Services District's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in April 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Twain Harte Community Services District's water quality report?
As a community water system, Twain Harte Community Services District must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Tuolumne County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Tud - Upper Basin Water System | Tuolumne | 13,280 | Community | Surface water |
| Tud - Sonora/Jamestown Water System | Tuolumne | 11,054 | Community | Surface water |
| Tud - Columbia Water System | Tuolumne | 5,463 | Community | Surface water |
| Peppery Bar and Grill, the | Tuolumne | 4,500 | Transient non-community | Groundwater |
| Cdcr - Sierra Conservation Center | Tuolumne | 3,571 | Community | Surface water |
| Groveland Community Serv Dist | Tuolumne | 3,400 | Community | Surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Twain Harte Community Services District, PWSID CA5510005, California”, https://aquacensus.com/water-systems/california/twain-harte-community-services-district-ca5510005 (data as of October 1, 2026).