Public water system · CA0410005
ActiveCal-Water Service Co.-Oroville
At a glance
Cal-Water Service Co.-Oroville (PWSID CA0410005) is an active community water system in Butte County, California. It reports serving 11,106 people through 3,528 service connections. Its primary water source is surface water, and EPA lists it as privately owned. EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
11,106
Service connections
3,528
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Cal-Water Service Co.-Oroville compare with other water systems in Butte County?
By EPA's size categories, Cal-Water Service Co.-Oroville is a large system (10,001 to 100,000 people). Butte County has 86 active public water systems, and Cal-Water Service Co.-Oroville is the 5th-largest of them by population served. Its population served is about 4.1 times the county average of 2,697 people per system, and accounts for 4.8% 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.-Oroville is about 66% above 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 609 California systems (8.1%) list surface water as their primary source.
Who owns and regulates Cal-Water Service Co.-Oroville?
EPA lists Cal-Water Service Co.-Oroville 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.-Oroville have drinking water violations?
EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2022. The violations listed here began between June 1996 and January 2022. By type: 1 monitoring and 1 contaminant level above the legal limit. The contaminants or rules involved are Revised Total Coliform Rule and Total coliform bacteria (TCR). EPA lists 2 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 |
|---|---|---|---|---|
| 2022-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 1996-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 2 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.-Oroville: frequently asked questions
Who runs Cal-Water Service Co.-Oroville?
Cal-Water Service Co.-Oroville (PWSID CA0410005) 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.-Oroville serve?
Cal-Water Service Co.-Oroville reports serving 11,106 people through 3,528 service connections in Butte County, California.
Where does Cal-Water Service Co.-Oroville get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Cal-Water Service Co.-Oroville have any drinking water violations?
EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2022. 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.-Oroville'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 2 violations for this system; 1 is health-based, and the most recent began in January 2022. 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.-Oroville's water quality report?
As a community water system, Cal-Water Service Co.-Oroville 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 |
| 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.-Oroville, PWSID CA0410005, California”, https://aquacensus.com/water-systems/california/cal-water-service-co-oroville-ca0410005 (data as of October 1, 2026).