Public water system · CA2210901
ActiveMpwd-Coulterville Csa 1
At a glance
Mpwd-Coulterville Csa 1 (PWSID CA2210901) is an active community water system in Mariposa County, California. It reports serving 193 people through 83 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 11 violations for this system; 4 are health-based, and the most recent began in February 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
193
Service connections
83
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mpwd-Coulterville Csa 1 compare with other water systems in Mariposa County?
By EPA's size categories, Mpwd-Coulterville Csa 1 is a very small system (500 people or fewer). Mariposa County has 67 active public water systems. Its population served is about half of the county average of 381 people per system, and accounts for 0.8% of the 25,508 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 Mpwd-Coulterville Csa 1 is well 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. 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 Mpwd-Coulterville Csa 1?
EPA lists Mpwd-Coulterville Csa 1 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. 21 of the 67 active systems in Mariposa County (31%) are also owned by a local government.
Does Mpwd-Coulterville Csa 1 have drinking water violations?
EPA's records list 11 violations for this system; 4 are health-based, and the most recent began in February 2022. The violations listed here began between July 1993 and February 2022. By type: 5 monitoring and reporting, 4 contaminant level above the legal limit and 2 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (7 of them). EPA lists 11 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 |
|---|---|---|---|---|
| 2022-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2015-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2014-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2011-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2008-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1999-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-01-02 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
All 11 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.
Mpwd-Coulterville Csa 1: frequently asked questions
Who runs Mpwd-Coulterville Csa 1?
Mpwd-Coulterville Csa 1 (PWSID CA2210901) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Mpwd-Coulterville Csa 1 serve?
Mpwd-Coulterville Csa 1 reports serving 193 people through 83 service connections in Mariposa County, California.
Where does Mpwd-Coulterville Csa 1 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 Mpwd-Coulterville Csa 1 have any drinking water violations?
EPA's records list 11 violations for this system; 4 are health-based, and the most recent began in February 2022. 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 Mpwd-Coulterville Csa 1'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 11 violations for this system; 4 are health-based, and the most recent began in February 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Mpwd-Coulterville Csa 1's water quality report?
As a community water system, Mpwd-Coulterville Csa 1 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 Mariposa County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Yosemite Nps-Glacier Point | Mariposa | 4,000 | Transient non-community | Surface water |
| Blm-Briceburg Water System | Mariposa | 3,196 | Transient non-community | Groundwater |
| Mariposa Public Utility Dist | Mariposa | 2,000 | Community | Surface water |
| Yosemite Nps-Bridalveil Fall | Mariposa | 1,163 | Transient non-community | Groundwater |
| Mid - Mc Swain Rec Area | Mariposa | 1,119 | Transient non-community | Surface water |
| Yosemite Nps-Yosemite Valley | Mariposa | 1,000 | 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, “Mpwd-Coulterville Csa 1, PWSID CA2210901, California”, https://aquacensus.com/water-systems/california/mpwd-coulterville-csa-1-ca2210901 (data as of October 1, 2026).