Public water system · CA2300832
ActiveHills Ranch Mutual Water Company
At a glance
Hills Ranch Mutual Water Company (PWSID CA2300832) is an active community water system in Mendocino County, California. It reports serving 79 people through 48 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 2 violations for this system; all are health-based, and the most recent began in October 2005.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
79
Service connections
48
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hills Ranch Mutual Water Company compare with other water systems in Mendocino County?
By EPA's size categories, Hills Ranch Mutual Water Company is a very small system (500 people or fewer). Mendocino County has 144 active public water systems. Its population served is well below the county average of 576 people per system, and accounts for less than 0.1% of the 82,868 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 Hills Ranch Mutual Water Company 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 Hills Ranch Mutual Water Company?
EPA lists Hills Ranch Mutual Water Company 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. 98 of the 144 active systems in Mendocino County (68%) are also privately owned.
Does Hills Ranch Mutual Water Company have drinking water violations?
EPA's records list 2 violations for this system; all are health-based, and the most recent began in October 2005. The violations listed here began between April 2005 and October 2005. By type: 2 contaminant level above the legal limit. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (2 of them). EPA lists 2 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 |
|---|---|---|---|---|
| 2005-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2005-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
All 2 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.
Hills Ranch Mutual Water Company: frequently asked questions
Who runs Hills Ranch Mutual Water Company?
Hills Ranch Mutual Water Company (PWSID CA2300832) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Hills Ranch Mutual Water Company serve?
Hills Ranch Mutual Water Company reports serving 79 people through 48 service connections in Mendocino County, California.
Where does Hills Ranch Mutual Water Company 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 Hills Ranch Mutual Water Company have any drinking water violations?
EPA's records list 2 violations for this system; all are health-based, and the most recent began in October 2005. 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 Hills Ranch Mutual Water Company'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 2 violations for this system; all are health-based, and the most recent began in October 2005. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Hills Ranch Mutual Water Company's water quality report?
As a community water system, Hills Ranch Mutual Water Company 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 Mendocino County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Ukiah, City of | Mendocino | 16,607 | Community | Surface water |
| Fort Bragg, City of | Mendocino | 6,919 | Community | Surface water |
| Willits, City of | Mendocino | 6,175 | Community | Surface water |
| Millview County Water District | Mendocino | 5,500 | Community | Surface water |
| Redwood Valley County Water District | Mendocino | 5,200 | Community | Surface water |
| Willow County Water District | Mendocino | 3,797 | Community | Purchased surface water |
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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, “Hills Ranch Mutual Water Company, PWSID CA2300832, California”, https://aquacensus.com/water-systems/california/hills-ranch-mutual-water-company-ca2300832 (data as of October 1, 2026).