Public water system · CA0410002
ActiveCal-Water Service Co.-Chico
At a glance
Cal-Water Service Co.-Chico (PWSID CA0410002) is an active community water system in Butte County, California. It reports serving 114,925 people through 30,396 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 5 violations for this system; all are health-based, and the most recent began in September 2002.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
114,925
Service connections
30,396
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Cal-Water Service Co.-Chico compare with other water systems in Butte County?
By EPA's size categories, Cal-Water Service Co.-Chico is a very large system (more than 100,000 people). Butte County has 86 active public water systems, and Cal-Water Service Co.-Chico is the largest of them by population served. Its population served is about 43 times the county average of 2,697 people per system, and accounts for 50% 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 Cal-Water Service Co.-Chico is about 17 times 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 Cal-Water Service Co.-Chico?
EPA lists Cal-Water Service Co.-Chico 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 Cal-Water Service Co.-Chico have drinking water violations?
EPA's records list 5 violations for this system; all are health-based, and the most recent began in September 2002. The violations listed here began between September 1992 and September 2002. By type: 5 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 5 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 |
|---|---|---|---|---|
| 2002-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Tetrachloroethylenecode 2987 | Yes | Resolved |
| 1992-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1992-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1992-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
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.
Cal-Water Service Co.-Chico: frequently asked questions
Who runs Cal-Water Service Co.-Chico?
Cal-Water Service Co.-Chico (PWSID CA0410002) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Cal-Water Service Co.-Chico serve?
Cal-Water Service Co.-Chico reports serving 114,925 people through 30,396 service connections in Butte County, California.
Where does Cal-Water Service Co.-Chico 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 Cal-Water Service Co.-Chico have any drinking water violations?
EPA's records list 5 violations for this system; all are health-based, and the most recent began in September 2002. 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 Cal-Water Service Co.-Chico'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; all are health-based, and the most recent began in September 2002. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Cal-Water Service Co.-Chico's water quality report?
As a community water system, Cal-Water Service Co.-Chico 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 |
|---|---|---|---|---|
| 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 |
| Paradise Irrigation District | Butte | 9,142 | Community | 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, “Cal-Water Service Co.-Chico, PWSID CA0410002, California”, https://aquacensus.com/water-systems/california/cal-water-service-co-chico-ca0410002 (data as of October 1, 2026).