Public water system · CA3810001
ActiveSan Francisco Regional Water System
At a glance
San Francisco Regional Water System (PWSID CA3810001) is an active community water system in San Francisco County, California. It reports serving 600 people through 256 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in June 1998.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
600
Service connections
256
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does San Francisco Regional Water System compare with other water systems in San Francisco County?
By EPA's size categories, San Francisco Regional Water System is a small system (501 to 3,300 people). San Francisco County has 8 active public water systems, and San Francisco Regional Water System is the 5th-largest of them by population served. Its population served is well below the county average of 130,038 people per system, and accounts for less than 0.1% of the 1,040,304 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 San Francisco Regional Water System 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 San Francisco Regional Water System?
EPA lists San Francisco Regional Water System as owned by a local government. 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. 6 of the 8 active systems in San Francisco County (75%) are also owned by a local government.
Does San Francisco Regional Water System have drinking water violations?
EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in June 1998. The violations listed here began between April 1991 and June 1998. By type: 4 required treatment not met, 2 monitoring and reporting and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Surface Water Treatment Rule (4 of them). EPA lists 7 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 |
|---|---|---|---|---|
| 1998-06-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1996-08-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Antimonycode 1074 | No | Resolved |
| 1995-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1995-03-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1993-06-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1992-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1991-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 7 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.
San Francisco Regional Water System: frequently asked questions
Who runs San Francisco Regional Water System?
San Francisco Regional Water System (PWSID CA3810001) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does San Francisco Regional Water System serve?
San Francisco Regional Water System reports serving 600 people through 256 service connections in San Francisco County, California.
Where does San Francisco Regional Water System 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 San Francisco Regional Water System have any drinking water violations?
EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in June 1998. 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 San Francisco Regional Water System'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 7 violations for this system; 5 are health-based, and the most recent began in June 1998. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find San Francisco Regional Water System's water quality report?
As a community water system, San Francisco Regional Water System 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 Francisco County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Sfpuc City Distribution Division | San Francisco | 848,019 | Community | Purchased surface water |
| San Francisco International Airport | San Francisco | 183,386 | Non-transient non-community | Purchased surface water |
| Treasure Island | San Francisco | 3,864 | Community | Purchased surface water |
| Presidio of San Francisco | San Francisco | 3,500 | Community | Surface water |
| Hhw&P-O'Shaughnessy Dam Cpd-Sfpuc | San Francisco | 495 | Transient non-community | Surface water |
| Hhw&P Moccasin Compound-Sfpuc | San Francisco | 410 | 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, “San Francisco Regional Water System, PWSID CA3810001, California”, https://aquacensus.com/water-systems/california/san-francisco-regional-water-system-ca3810001 (data as of October 1, 2026).