Public water system · CA2110002
ActiveMarin Municipal Water District
At a glance
Marin Municipal Water District (PWSID CA2110002) is an active community water system in Marin County, California. It reports serving 186,895 people through 60,868 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's Safe Drinking Water Act records list no violations for this system.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
186,895
Service connections
60,868
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Marin Municipal Water District compare with other water systems in Marin County?
By EPA's size categories, Marin Municipal Water District is a very large system (more than 100,000 people). Marin County has 46 active public water systems, and Marin Municipal Water District is the largest of them by population served. Its population served is about 30 times the county average of 6,203 people per system, and accounts for 65% 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 community water system reports serving 6,703 people, so Marin Municipal Water District is about 28 times 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 Marin Municipal Water District?
EPA lists Marin Municipal Water 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. 12 of the 46 active systems in Marin County (26%) are also owned by a local government.
Does Marin Municipal Water District have drinking water violations?
No SDWA violations on record.
EPA's SDWA violation and enforcement data (via EPA ECHO, updated quarterly) lists no violations for Marin Municipal Water District. For the latest compliance status, check EPA ECHO for current compliance history.
Marin Municipal Water District: frequently asked questions
Who runs Marin Municipal Water District?
Marin Municipal Water District (PWSID CA2110002) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Marin Municipal Water District serve?
Marin Municipal Water District reports serving 186,895 people through 60,868 service connections in Marin County, California.
Where does Marin Municipal Water 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 Marin Municipal Water District have any drinking water violations?
EPA's Safe Drinking Water Act records list no violations for this system.
Is Marin Municipal Water 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 Safe Drinking Water Act records list no violations for this system. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Marin Municipal Water District's water quality report?
As a community water system, Marin Municipal Water 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 Marin County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| 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 |
| Nps Prns - Beaches | Marin | 1,560 | 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, “Marin Municipal Water District, PWSID CA2110002, California”, https://aquacensus.com/water-systems/california/marin-municipal-water-district-ca2110002 (data as of October 1, 2026).