Public water system · CA3700933
ActivePalomar Mountain Mutual Water Co.
At a glance
Palomar Mountain Mutual Water Co. (PWSID CA3700933) is an active community water system in San Diego County, California. It reports serving 193 people through 195 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, 3 are health-based, and the most recent began in April 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
193
Service connections
195
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Palomar Mountain Mutual Water Co. compare with other water systems in San Diego County?
By EPA's size categories, Palomar Mountain Mutual Water Co. is a very small system (500 people or fewer). San Diego County has 191 active public water systems. Its population served is well below the county average of 19,427 people per system, and accounts for less than 0.1% of the 3,710,459 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 Palomar Mountain Mutual Water Co. 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 Palomar Mountain Mutual Water Co.?
EPA lists Palomar Mountain Mutual Water Co. 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. 101 of the 191 active systems in San Diego County (53%) are also privately owned.
Does Palomar Mountain Mutual Water Co. have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in April 2023. The violations listed here began between September 1984 and April 2023. By type: 4 monitoring, 3 contaminant level above the legal limit, 3 monitoring and reporting and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Revised Total Coliform Rule (5 of them). EPA lists 11 as resolved and 1 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 |
|---|---|---|---|---|
| 2023-04-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-11-01 | Public notice, recordkeeping or otherSample Siting Plan Errors (RTCR) · code 5A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2010-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | 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 |
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.
Palomar Mountain Mutual Water Co.: frequently asked questions
Who runs Palomar Mountain Mutual Water Co.?
Palomar Mountain Mutual Water Co. (PWSID CA3700933) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Palomar Mountain Mutual Water Co. serve?
Palomar Mountain Mutual Water Co. reports serving 193 people through 195 service connections in San Diego County, California.
Where does Palomar Mountain Mutual Water Co. 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 Palomar Mountain Mutual Water Co. have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in April 2023. 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 Palomar Mountain Mutual Water Co.'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, 3 are health-based, and the most recent began in April 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Palomar Mountain Mutual Water Co.'s water quality report?
As a community water system, Palomar Mountain Mutual Water Co. 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 San Diego County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| San Diego, City of | San Diego | 1,385,379 | Community | Surface water |
| Helix Water District | San Diego | 277,668 | Community | Surface water |
| Otay Water District | San Diego | 238,008 | Community | Purchased surface water |
| Sweetwater Authority | San Diego | 191,282 | Community | Surface water |
| Oceanside, City of | San Diego | 171,483 | Community | Purchased surface water |
| Escondido, City of | San Diego | 137,044 | 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, “Palomar Mountain Mutual Water Co., PWSID CA3700933, California”, https://aquacensus.com/water-systems/california/palomar-mountain-mutual-water-co-ca3700933 (data as of October 1, 2026).