Public water system · CA2410012
ActiveHilmar County Water District
At a glance
Hilmar County Water District (PWSID CA2410012) is an active community water system in Merced County, California. It reports serving 5,504 people through 1,684 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in November 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
5,504
Service connections
1,684
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hilmar County Water District compare with other water systems in Merced County?
By EPA's size categories, Hilmar County Water District is a medium system (3,301 to 10,000 people). Merced County has 120 active public water systems. Its population served is about 147% above the county average of 2,228 people per system, and accounts for 2.1% of the 267,324 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 Hilmar County Water District is about 18% 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 Hilmar County Water District?
EPA lists Hilmar County 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. 30 of the 120 active systems in Merced County (25%) are also owned by a local government.
Does Hilmar County Water District have drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in November 2025. The violations listed here began between February 2024 and November 2025. By type: 12 contaminant level above the legal limit. The contaminant or rule involved most often is Nitrate (12 of them). EPA lists 12 as archived. 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 |
|---|---|---|---|---|
| 2025-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
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.
Hilmar County Water District: frequently asked questions
Who runs Hilmar County Water District?
Hilmar County Water District (PWSID CA2410012) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Hilmar County Water District serve?
Hilmar County Water District reports serving 5,504 people through 1,684 service connections in Merced County, California.
Where does Hilmar County Water District 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 Hilmar County Water District 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 November 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 Hilmar County 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. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in November 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 Hilmar County Water District's water quality report?
As a community water system, Hilmar County 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 Merced County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Merced | Merced | 93,692 | Community | Groundwater |
| City of Los Banos | Merced | 47,419 | Community | Groundwater |
| City of Atwater | Merced | 29,479 | Community | Groundwater |
| City of Livingston | Merced | 14,894 | Community | Groundwater |
| Winton Water & Sanitary Dist | Merced | 9,745 | Community | Groundwater |
| Delhi Cwd | Merced | 7,784 | 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, “Hilmar County Water District, PWSID CA2410012, California”, https://aquacensus.com/water-systems/california/hilmar-county-water-district-ca2410012 (data as of October 1, 2026).