Public water system · CA0600008
ActiveColusa Co. Wwd #1 - Grimes
At a glance
Colusa Co. Wwd #1 - Grimes (PWSID CA0600008) is an active community water system in Colusa County, California. It reports serving 512 people through 114 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, 9 are health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
512
Service connections
114
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Colusa Co. Wwd #1 - Grimes compare with other water systems in Colusa County?
By EPA's size categories, Colusa Co. Wwd #1 - Grimes is a small system (501 to 3,300 people). Colusa County has 29 active public water systems. Its population served is about 58% below the county average of 1,211 people per system, and accounts for 1.5% of the 35,121 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 Colusa Co. Wwd #1 - Grimes 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 Colusa Co. Wwd #1 - Grimes?
EPA lists Colusa Co. Wwd #1 - Grimes 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. 7 of the 29 active systems in Colusa County (24%) are also owned by a local government.
Does Colusa Co. Wwd #1 - Grimes have drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in October 2025. The violations listed here began between October 2022 and October 2025. By type: 9 contaminant level above the legal limit, 2 monitoring and reporting and 1 monitoring. The contaminant or rule involved most often is Arsenic (9 of them). EPA lists 9 as archived, 2 as resolved and 1 as unaddressed. 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. 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 |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2024-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2023-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2023-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2023-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2023-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2023-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2022-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | 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.
Colusa Co. Wwd #1 - Grimes: frequently asked questions
Who runs Colusa Co. Wwd #1 - Grimes?
Colusa Co. Wwd #1 - Grimes (PWSID CA0600008) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Colusa Co. Wwd #1 - Grimes serve?
Colusa Co. Wwd #1 - Grimes reports serving 512 people through 114 service connections in Colusa County, California.
Where does Colusa Co. Wwd #1 - Grimes 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 Colusa Co. Wwd #1 - Grimes have any drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in October 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 Colusa Co. Wwd #1 - Grimes' 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, 9 are health-based, and the most recent began in October 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 Colusa Co. Wwd #1 - Grimes' water quality report?
As a community water system, Colusa Co. Wwd #1 - Grimes 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 Colusa County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Caltrans-Maxwell Reststops | Colusa | 15,000 | Transient non-community | Groundwater |
| City of Colusa | Colusa | 6,447 | Community | Groundwater |
| City of Williams | Colusa | 5,538 | Community | Groundwater |
| Arbuckle Public Utility District | Colusa | 2,778 | Community | Groundwater |
| Maxwell Public Utility District | Colusa | 1,175 | Community | Groundwater |
| Colusa Industrial Properties | Colusa | 533 | Non-transient non-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, “Colusa Co. Wwd #1 - Grimes, PWSID CA0600008, California”, https://aquacensus.com/water-systems/california/colusa-co-wwd-1-grimes-ca0600008 (data as of October 1, 2026).