Public water system · CA2810003
ActiveNapa, City of
At a glance
City of Napa (PWSID CA2810003) is an active community water system in Napa County, California. It reports serving 84,804 people through 25,376 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
84,804
Service connections
25,376
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Napa compare with other water systems in Napa County?
By EPA's size categories, City of Napa is a large system (10,001 to 100,000 people). Napa County has 188 active public water systems, and City of Napa is the largest of them by population served. Its population served is about 98 times the county average of 861 people per system, and accounts for 52% of the 161,950 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 City of Napa is about 13 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 City of Napa?
EPA lists City of Napa 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. 15 of the 188 active systems in Napa County (8%) are also owned by a local government.
Does City of Napa have drinking water violations?
EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016. The violations listed here began between July 1988 and January 2016. By type: 6 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 1 required treatment not met. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (5 of them). EPA lists 7 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 |
|---|---|---|---|---|
| 2016-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 1995-04-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1988-08-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1988-07-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
All 9 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.
City of Napa: frequently asked questions
Who runs City of Napa?
City of Napa (PWSID CA2810003) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does City of Napa serve?
City of Napa reports serving 84,804 people through 25,376 service connections in Napa County, California.
Where does City of Napa 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 City of Napa have any drinking water violations?
EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016. 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 City of Napa'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 9 violations for this system; 7 are health-based, and the most recent began in January 2016. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find City of Napa's water quality report?
As a community water system, City of Napa 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 Napa County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| American Canyon, City of | Napa | 21,437 | Community | Surface water |
| Phelps Vineyards | Napa | 19,412 | Non-transient non-community | Groundwater |
| Calistoga, City of | Napa | 5,610 | Community | Surface water |
| St. Helena, City of | Napa | 5,386 | Community | Surface water |
| Town of Yountville | Napa | 2,787 | Community | Purchased surface water |
| Pacific Union College | Napa | 1,958 | 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, “Napa, City of, PWSID CA2810003, California”, https://aquacensus.com/water-systems/california/napa-city-of-ca2810003 (data as of October 1, 2026).