Public water system · CA0400003
ActiveHartley Mutual Water System
At a glance
Hartley Mutual Water System (PWSID CA0400003) is an active community water system in Butte County, California. It reports serving 41 people through 15 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
41
Service connections
15
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hartley Mutual Water System compare with other water systems in Butte County?
By EPA's size categories, Hartley Mutual Water System is a very small system (500 people or fewer). Butte County has 86 active public water systems. Its population served is well below the county average of 2,697 people per system, and accounts for less than 0.1% of the 231,911 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 Hartley Mutual Water System 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 Hartley Mutual Water System?
EPA lists Hartley Mutual Water System 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. 23 of the 86 active systems in Butte County (27%) are also owned by a local government.
Does Hartley Mutual Water System have drinking water violations?
EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in October 2024. The violations listed here began between October 1980 and October 2024. By type: 3 monitoring and reporting, 2 public notice, recordkeeping or other, 1 reporting and 1 required treatment not met. The contaminant or rule involved most often is Lead and Copper Rule Revisions (2 of them). EPA lists 3 as archived, 2 as unaddressed and 2 as resolved. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement. 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 |
|---|---|---|---|---|
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Unaddressed |
| 2014-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1983-07-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1981-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
| 1980-10-30 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 7 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.
Hartley Mutual Water System: frequently asked questions
Who runs Hartley Mutual Water System?
Hartley Mutual Water System (PWSID CA0400003) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Hartley Mutual Water System serve?
Hartley Mutual Water System reports serving 41 people through 15 service connections in Butte County, California.
Where does Hartley Mutual Water System 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 Hartley Mutual Water System have any drinking water violations?
EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in October 2024. 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 Hartley Mutual Water System'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 7 violations for this system; 1 is health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Hartley Mutual Water System's water quality report?
As a community water system, Hartley Mutual Water System 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 Butte County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Cal-Water Service Co.-Chico | Butte | 114,925 | Community | Groundwater |
| South Feather W&P - Miners Ranch | Butte | 22,664 | Community | Surface water |
| Butte-Glenn Community College Dist | Butte | 18,000 | Non-transient non-community | Groundwater |
| Thermalito Water & Sewer Dist | Butte | 12,136 | Community | Surface water |
| Cal-Water Service Co.-Oroville | Butte | 11,106 | Community | Surface water |
| Del Oro Water Co.-Paradise Pines | Butte | 10,940 | Community | Purchased surface water |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Hartley Mutual Water System, PWSID CA0400003, California”, https://aquacensus.com/water-systems/california/hartley-mutual-water-system-ca0400003 (data as of October 1, 2026).