Public water system · CA4900513
ActiveMadrone Mutual Water Company
At a glance
Madrone Mutual Water Company (PWSID CA4900513) is an active community water system in Sonoma County, California. It reports serving 76 people through 23 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in May 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
76
Service connections
23
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Madrone Mutual Water Company compare with other water systems in Sonoma County?
By EPA's size categories, Madrone Mutual Water Company 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 Madrone Mutual Water Company 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 Madrone Mutual Water Company?
EPA lists Madrone Mutual Water Company 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 Madrone Mutual Water Company have drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in May 2015. The violations listed here began between August 1984 and May 2015. By type: 9 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (10 of them). EPA lists 10 as resolved and 2 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 |
|---|---|---|---|---|
| 2015-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1984-09-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-08-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | 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.
Madrone Mutual Water Company: frequently asked questions
Who runs Madrone Mutual Water Company?
Madrone Mutual Water Company (PWSID CA4900513) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Madrone Mutual Water Company serve?
Madrone Mutual Water Company reports serving 76 people through 23 service connections in Sonoma County, California.
Where does Madrone Mutual Water Company 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 Madrone Mutual Water Company 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 May 2015. 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 Madrone Mutual Water Company'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. Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in May 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Madrone Mutual Water Company's water quality report?
As a community water system, Madrone Mutual Water Company 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 |
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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, “Madrone Mutual Water Company, PWSID CA4900513, California”, https://aquacensus.com/water-systems/california/madrone-mutual-water-company-ca4900513 (data as of October 1, 2026).