Public water system · CA0410004
ActiveCity of Gridley
At a glance
City of Gridley (PWSID CA0410004) is an active community water system in Butte County, California. It reports serving 7,269 people through 2,282 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
7,269
Service connections
2,282
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Gridley compare with other water systems in Butte County?
By EPA's size categories, City of Gridley is a medium system (3,301 to 10,000 people). Butte County has 86 active public water systems. Its population served is about 170% above the county average of 2,697 people per system, and accounts for 3.1% 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 City of Gridley is roughly in line with 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 City of Gridley?
EPA lists City of Gridley 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 City of Gridley have drinking water violations?
EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in October 2024. The violations listed here began between March 1999 and October 2024. By type: 3 contaminant level above the legal limit, 1 required treatment not met, 1 reporting and 1 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule Revisions (2 of them). EPA lists 4 as resolved and 2 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Unaddressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2008-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2007-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1999-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 6 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.
City of Gridley: frequently asked questions
Who runs City of Gridley?
City of Gridley (PWSID CA0410004) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does City of Gridley serve?
City of Gridley reports serving 7,269 people through 2,282 service connections in Butte County, California.
Where does City of Gridley 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 City of Gridley have any drinking water violations?
EPA's records list 6 violations for this system; 4 are 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 City of Gridley'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 6 violations for this system; 4 are 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 City of Gridley's water quality report?
As a community water system, City of Gridley 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 |
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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, “City of Gridley, PWSID CA0410004, California”, https://aquacensus.com/water-systems/california/city-of-gridley-ca0410004 (data as of October 1, 2026).