Public water system · CA3010004
ActiveMesa Water District
At a glance
Mesa Water District (PWSID CA3010004) is an active community water system in Orange County, California. It reports serving 110,000 people through 24,436 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2010.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
110,000
Service connections
24,436
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Mesa Water District compare with other water systems in Orange County?
By EPA's size categories, Mesa Water District is a very large system (more than 100,000 people). Orange County has 46 active public water systems. Its population served is about 58% above the county average of 69,606 people per system, and accounts for 3.4% of the 3,201,893 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 Mesa Water District is about 16 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 506 California systems (6.8%) list purchased surface water as their primary source.
Who owns and regulates Mesa Water District?
EPA lists Mesa Water District 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. 34 of the 46 active systems in Orange County (74%) are also owned by a local government.
Does Mesa Water District have drinking water violations?
EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2010. The violations listed here began between July 2000 and January 2010. By type: 1 monitoring and reporting and 1 contaminant level above the legal limit. The contaminants or rules involved are Combined Uranium and Total coliform bacteria (TCR). EPA lists 2 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 |
|---|---|---|---|---|
| 2010-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Uraniumcode 4006 | No | Resolved |
| 2000-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 2 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.
Mesa Water District: frequently asked questions
Who runs Mesa Water District?
Mesa Water District (PWSID CA3010004) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Mesa Water District serve?
Mesa Water District reports serving 110,000 people through 24,436 service connections in Orange County, California.
Where does Mesa Water District get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Mesa Water District have any drinking water violations?
EPA's records list 2 violations for this system; 1 is health-based, and the most recent began in January 2010. 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 Mesa Water District'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 2 violations for this system; 1 is health-based, and the most recent began in January 2010. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Mesa Water District's water quality report?
As a community water system, Mesa Water District 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 Orange County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Irvine Ranch Water District | Orange | 444,800 | Community | Surface water |
| City of Anaheim | Orange | 348,593 | Community | Surface water |
| City of Santa Ana | Orange | 310,539 | Community | Purchased surface water |
| City of Huntington Beach | Orange | 201,000 | Community | Purchased surface water |
| City of Garden Grove | Orange | 174,226 | Community | Purchased surface water |
| Moulton Niguel Water District | Orange | 170,236 | 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, “Mesa Water District, PWSID CA3010004, California”, https://aquacensus.com/water-systems/california/mesa-water-district-ca3010004 (data as of October 1, 2026).