Public water system · CA2100582
ActiveNicasio School
At a glance
Nicasio School (PWSID CA2100582) is an active non-transient non-community water system in Marin County, California. It reports serving 48 people through 5 service connections. Its primary water source is groundwater under influence of surface water, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in October 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
48
Service connections
5
Primary source
GU
Groundwater under influence of surface water
System type
NTNCWS
Non-transient non-community water system
System record
How does Nicasio School compare with other water systems in Marin County?
By EPA's size categories, Nicasio 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 Nicasio School is well below 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 under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules. 105 California systems (1.4%) list groundwater under influence of surface water as their primary source.
Who owns and regulates Nicasio School?
EPA lists Nicasio School as privately owned. 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. 22 of the 46 active systems in Marin County (48%) are also privately owned.
Does Nicasio School have drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in October 2021. The violations listed here began between October 2013 and October 2021. By type: 12 contaminant level above the legal limit. The contaminant or rule involved most often is Haloacetic acids (HAA5) (12 of them). EPA lists 12 as resolved. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2021-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2021-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2021-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2020-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2020-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2018-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2018-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2018-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2016-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2013-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
The 12 most recent 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.
Nicasio School: frequently asked questions
Who runs Nicasio School?
Nicasio School (PWSID CA2100582) is a non-transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Nicasio School serve?
Nicasio School reports serving 48 people through 5 service connections in Marin County, California.
Where does Nicasio School get its water?
EPA SDWIS lists this system's primary water source as groundwater under influence of surface water. Groundwater under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules.
Does Nicasio School have any drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in October 2021. 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 Nicasio 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. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in October 2021. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Nicasio School's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Nicasio 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, “Nicasio School, PWSID CA2100582, California”, https://aquacensus.com/water-systems/california/nicasio-school-ca2100582 (data as of October 1, 2026).