Public water system · CA0600012
ActiveColusa Co. Service Area #1-Century Ranch
At a glance
Colusa Co. Service Area #1-Century Ranch (PWSID CA0600012) is an active community water system in Colusa County, California. It reports serving 246 people through 88 service connections. Its primary water source is surface water, and EPA lists it as privately owned. EPA's records list 4 violations for this system; none is health-based, and the most recent began in November 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
246
Service connections
88
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Colusa Co. Service Area #1-Century Ranch compare with other water systems in Colusa County?
By EPA's size categories, Colusa Co. Service Area #1-Century Ranch is a very small system (500 people or fewer). Colusa County has 29 active public water systems. Its population served is well below the county average of 1,211 people per system, and accounts for 0.7% 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. Service Area #1-Century Ranch 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. 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 Colusa Co. Service Area #1-Century Ranch?
EPA lists Colusa Co. Service Area #1-Century Ranch 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. 19 of the 29 active systems in Colusa County (66%) are also privately owned.
Does Colusa Co. Service Area #1-Century Ranch have drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in November 2022. The violations listed here began between January 2018 and November 2022. By type: 2 monitoring, 1 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Revised Total Coliform Rule (2 of them). EPA lists 4 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 |
|---|---|---|---|---|
| 2022-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2021-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
All 4 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. Service Area #1-Century Ranch: frequently asked questions
Who runs Colusa Co. Service Area #1-Century Ranch?
Colusa Co. Service Area #1-Century Ranch (PWSID CA0600012) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Colusa Co. Service Area #1-Century Ranch serve?
Colusa Co. Service Area #1-Century Ranch reports serving 246 people through 88 service connections in Colusa County, California.
Where does Colusa Co. Service Area #1-Century Ranch 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 Colusa Co. Service Area #1-Century Ranch have any drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in November 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 Colusa Co. Service Area #1-Century Ranch'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 4 violations for this system; none is health-based, and the most recent began in November 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 Colusa Co. Service Area #1-Century Ranch's water quality report?
As a community water system, Colusa Co. Service Area #1-Century Ranch 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. Service Area #1-Century Ranch, PWSID CA0600012, California”, https://aquacensus.com/water-systems/california/colusa-co-service-area-1-century-ranch-ca0600012 (data as of October 1, 2026).