Public water system · CA0400008
ActiveGran Mutual Water Co
At a glance
Gran Mutual Water Co (PWSID CA0400008) is an active community water system in Butte County, California. It reports serving 290 people through 91 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
290
Service connections
91
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Gran Mutual Water Co compare with other water systems in Butte County?
By EPA's size categories, Gran Mutual Water Co 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 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 Gran Mutual Water Co 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 Gran Mutual Water Co?
EPA lists Gran Mutual Water Co 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. 58 of the 86 active systems in Butte County (67%) are also privately owned.
Does Gran Mutual Water Co have drinking water violations?
EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in July 2025. The violations listed here began between October 1981 and July 2025. By type: 3 monitoring and reporting, 1 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminants or rules involved are Consumer Confidence Rule, Total coliform bacteria (TCR), Benzene and Lead and Copper Rule. EPA lists 4 as resolved and 1 as archived. 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. 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 |
|---|---|---|---|---|
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2014-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzenecode 2990 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1981-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 5 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.
Gran Mutual Water Co: frequently asked questions
Who runs Gran Mutual Water Co?
Gran Mutual Water Co (PWSID CA0400008) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Gran Mutual Water Co serve?
Gran Mutual Water Co reports serving 290 people through 91 service connections in Butte County, California.
Where does Gran Mutual Water Co 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 Gran Mutual Water Co have any drinking water violations?
EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in July 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 Gran Mutual Water Co'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 5 violations for this system; 1 is health-based, and the most recent began in July 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 Gran Mutual Water Co's water quality report?
As a community water system, Gran Mutual Water Co 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, “Gran Mutual Water Co, PWSID CA0400008, California”, https://aquacensus.com/water-systems/california/gran-mutual-water-co-ca0400008 (data as of October 1, 2026).