Public water system · CA4310011
ActiveSan Jose Water
At a glance
San Jose Water (PWSID CA4310011) is an active community water system in Santa Clara County, California. It reports serving 1,039,920 people through 237,130 service connections. Its primary water source is surface water, 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 June 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,039,920
Service connections
237,130
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does San Jose Water compare with other water systems in Santa Clara County?
By EPA's size categories, San Jose Water is a very large system (more than 100,000 people). Santa Clara County has 121 active public water systems, and San Jose Water is the largest of them by population served. Its population served is about 60 times the county average of 17,334 people per system, and accounts for 50% of the 2,097,447 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 Jose Water is about 155 times 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 Jose Water?
EPA lists San Jose Water 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. 82 of the 121 active systems in Santa Clara County (68%) are also privately owned.
Does San Jose Water have drinking water violations?
EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in June 2023. The violations listed here began between August 1997 and June 2023. By type: 2 required treatment not met, 1 monitoring and reporting and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Surface Water Treatment Rule (2 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 |
|---|---|---|---|---|
| 2023-06-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2017-04-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2000-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | 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.
San Jose Water: frequently asked questions
Who runs San Jose Water?
San Jose Water (PWSID CA4310011) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does San Jose Water serve?
San Jose Water reports serving 1,039,920 people through 237,130 service connections in Santa Clara County, California.
Where does San Jose Water 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 Jose Water have any drinking water violations?
EPA's records list 4 violations for this system; 3 are health-based, and the most recent began in June 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 San Jose Water'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 June 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 San Jose Water's water quality report?
As a community water system, San Jose Water 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 Santa Clara County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Sunnyvale | Santa Clara | 157,566 | Community | Purchased surface water |
| City of Santa Clara | Santa Clara | 130,746 | Community | Purchased surface water |
| Great Oaks Wc Inc. | Santa Clara | 110,088 | Community | Groundwater |
| City of San Jose - Evg/Edv/Coy | Santa Clara | 101,265 | Community | Purchased surface water |
| City of Milpitas | Santa Clara | 81,773 | Community | Purchased surface water |
| City of Mountain View | Santa Clara | 81,501 | 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 Jose Water, PWSID CA4310011, California”, https://aquacensus.com/water-systems/california/san-jose-water-ca4310011 (data as of October 1, 2026).