Public water system · CA2100538
ActiveTomales High School
At a glance
Tomales High School (PWSID CA2100538) is an active non-transient non-community water system in Marin County, California. It reports serving 200 people through 2 service connections. Its primary water source is groundwater, 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 October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
200
Service connections
2
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Tomales High School compare with other water systems in Marin County?
By EPA's size categories, Tomales High School is a very small system (500 people or fewer). Marin County has 46 active public water systems. Its population served is well below the county average of 6,203 people per system, and accounts for less than 0.1% of the 285,353 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active non-transient non-community water system reports serving 430 people, so Tomales High School is about half of that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. California has 1,466 active non-transient non-community water systems, 20% of the state's 7,479 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,179 California systems (83%) list groundwater as their primary source.
Who owns and regulates Tomales High School?
EPA lists Tomales High School 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. 12 of the 46 active systems in Marin County (26%) are also owned by a local government.
Does Tomales High School have drinking water violations?
EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in October 2024. The violations listed here began between August 1984 and October 2024. By type: 1 required treatment not met, 1 reporting, 1 contaminant level above the legal limit and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Lead and Copper Rule Revisions (2 of them). EPA lists 2 as addressed, 1 as resolved and 1 as archived. Addressed means the violation is not resolved or archived and is covered by formal enforcement. 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 |
|---|---|---|---|---|
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Addressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Addressed |
| 2003-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1984-08-01 | 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.
Tomales High School: frequently asked questions
Who runs Tomales High School?
Tomales High School (PWSID CA2100538) is a non-transient non-community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Tomales High School serve?
Tomales High School reports serving 200 people through 2 service connections in Marin County, California.
Where does Tomales High School get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Tomales High School have any drinking water violations?
EPA's records list 4 violations for this system; 2 are health-based, and the most recent began in October 2024. 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 Tomales High School'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 October 2024. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Tomales High School's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Tomales High School is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Marin County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Marin Municipal Water District | Marin | 186,895 | Community | Surface water |
| North Marin Water District | Marin | 61,691 | Community | Surface water |
| Nps Ggnra | Marin | 18,447 | Community | Purchased surface water |
| Bolinas Community PUD | Marin | 2,483 | Community | Surface water |
| North Marin Wd - Pt. Reyes | Marin | 1,841 | Community | Groundwater |
| Csp - Angel Island St Park | Marin | 1,622 | Transient non-community | Groundwater |
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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, “Tomales High School, PWSID CA2100538, California”, https://aquacensus.com/water-systems/california/tomales-high-school-ca2100538 (data as of October 1, 2026).