Public water system · CA4900721
ActiveColonial Park
At a glance
Colonial Park (PWSID CA4900721) is an active community water system in Sonoma County, California. It reports serving 342 people through 194 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 10 violations for this system; none is health-based, and the most recent began in October 2011.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
342
Service connections
194
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Colonial Park compare with other water systems in Sonoma County?
By EPA's size categories, Colonial Park is a very small system (500 people or fewer). Sonoma County has 441 active public water systems. Its population served is well below the county average of 1,092 people per system, and accounts for less than 0.1% of the 481,435 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 Colonial Park 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 Colonial Park?
EPA lists Colonial Park 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. 371 of the 441 active systems in Sonoma County (84%) are also privately owned.
Does Colonial Park have drinking water violations?
EPA's records list 10 violations for this system; none is health-based, and the most recent began in October 2011. The violations listed here began between October 1980 and October 2011. By type: 7 monitoring and reporting and 3 public notice, recordkeeping or other. The contaminant or rule involved most often is Nitrate (2 of them). EPA lists 5 as resolved and 5 as archived. 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. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2011-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2006-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2001-03-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1984-09-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-07-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1982-10-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1981-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
| 1980-10-30 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 10 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.
Colonial Park: frequently asked questions
Who runs Colonial Park?
Colonial Park (PWSID CA4900721) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Colonial Park serve?
Colonial Park reports serving 342 people through 194 service connections in Sonoma County, California.
Where does Colonial Park 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 Colonial Park have any drinking water violations?
EPA's records list 10 violations for this system; none is health-based, and the most recent began in October 2011. 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 Colonial Park'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 10 violations for this system; none is health-based, and the most recent began in October 2011. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Colonial Park's water quality report?
As a community water system, Colonial Park 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 Sonoma County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Santa Rosa, City of | Sonoma | 175,396 | Community | Groundwater |
| Petaluma, City of | Sonoma | 60,781 | Community | Groundwater |
| Rohnert Park, City of | Sonoma | 43,821 | Community | Groundwater |
| Windsor, Town of | Sonoma | 25,561 | Community | Groundwater |
| Valley of the Moon Water District | Sonoma | 23,107 | Community | Groundwater |
| Sonoma, City of | Sonoma | 11,725 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Colonial Park, PWSID CA4900721, California”, https://aquacensus.com/water-systems/california/colonial-park-ca4900721 (data as of October 1, 2026).