Public water system · CA4110019
ActiveO'Connor Tract Co-Operative Water Co.
At a glance
O'Connor Tract Co-Operative Water Co. (PWSID CA4110019) is an active community water system in San Mateo County, California. It reports serving 2,789 people through 359 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in April 2018.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,789
Service connections
359
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does O'Connor Tract Co-Operative Water Co. compare with other water systems in San Mateo County?
By EPA's size categories, O'Connor Tract Co-Operative Water Co. is a small system (501 to 3,300 people). San Mateo County has 51 active public water systems. Its population served is well below the county average of 15,363 people per system, and accounts for 0.4% of the 783,522 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 O'Connor Tract Co-Operative Water Co. is about 58% 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 O'Connor Tract Co-Operative Water Co.?
EPA lists O'Connor Tract Co-Operative 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. 27 of the 51 active systems in San Mateo County (53%) are also privately owned.
Does O'Connor Tract Co-Operative Water Co. have drinking water violations?
EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in April 2018. The violations listed here began between May 2000 and April 2018. By type: 2 contaminant level above the legal limit, 1 required treatment not met and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 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 |
|---|---|---|---|---|
| 2018-04-01 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2015-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2004-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2000-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | 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.
O'Connor Tract Co-Operative Water Co.: frequently asked questions
Who runs O'Connor Tract Co-Operative Water Co.?
O'Connor Tract Co-Operative Water Co. (PWSID CA4110019) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does O'Connor Tract Co-Operative Water Co. serve?
O'Connor Tract Co-Operative Water Co. reports serving 2,789 people through 359 service connections in San Mateo County, California.
Where does O'Connor Tract Co-Operative 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 O'Connor Tract Co-Operative Water Co. have any drinking water violations?
EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in April 2018. 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 O'Connor Tract Co-Operative 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. EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in April 2018. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find O'Connor Tract Co-Operative Water Co.'s water quality report?
As a community water system, O'Connor Tract Co-Operative 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 Mateo County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Daly City | San Mateo | 104,901 | Community | Purchased surface water |
| California Water Service - San Mateo | San Mateo | 102,348 | Community | Purchased surface water |
| City of Redwood City | San Mateo | 92,819 | Community | Purchased surface water |
| California Water Service-S San Francisco | San Mateo | 64,146 | Community | Purchased surface water |
| California Water Service - Bear Gulch | San Mateo | 61,431 | Community | Surface water |
| City of San Bruno | San Mateo | 42,631 | Community | Purchased 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, “O'Connor Tract Co-Operative Water Co., PWSID CA4110019, California”, https://aquacensus.com/water-systems/california/o-connor-tract-co-operative-water-co-ca4110019 (data as of October 1, 2026).