Public water system · CA1910126
ActivePomona - City, Water Dept.
At a glance
Pomona - City, Water Dept. (PWSID CA1910126) is an active community water system in Los Angeles County, California. It reports serving 151,713 people through 30,172 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list one violation for this system; it is health-based, and the most recent began in June 1993.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
151,713
Service connections
30,172
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Pomona - City, Water Dept. compare with other water systems in Los Angeles County?
By EPA's size categories, Pomona - City, Water Dept. is a very large system (more than 100,000 people). Los Angeles County has 275 active public water systems. Its population served is about 4.1 times the county average of 36,762 people per system, and accounts for 1.5% of the 10,109,668 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 Pomona - City, Water Dept. is about 23 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 Pomona - City, Water Dept.?
EPA lists Pomona - City, Water Dept. 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. 100 of the 275 active systems in Los Angeles County (36%) are also owned by a local government.
Does Pomona - City, Water Dept. have drinking water violations?
EPA's records list one violation for this system; it is health-based, and the most recent began in June 1993. By type: 1 required treatment not met. The contaminant or rule involved is Surface Water Treatment Rule. EPA lists 1 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 |
|---|---|---|---|---|
| 1993-06-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
The one violation in EPA's records.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.
Pomona - City, Water Dept.: frequently asked questions
Who runs Pomona - City, Water Dept.?
Pomona - City, Water Dept. (PWSID CA1910126) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Pomona - City, Water Dept. serve?
Pomona - City, Water Dept. reports serving 151,713 people through 30,172 service connections in Los Angeles County, California.
Where does Pomona - City, Water Dept. 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 Pomona - City, Water Dept. have any drinking water violations?
EPA's records list one violation for this system; it is health-based, and the most recent began in June 1993. 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 Pomona - City, Water Dept.'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 one violation for this system; it is health-based, and the most recent began in June 1993. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Pomona - City, Water Dept.'s water quality report?
As a community water system, Pomona - City, Water Dept. 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 Los Angeles County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Los Angeles-City, Dept. of Water & Power | Los Angeles | 3,875,566 | Community | Surface water |
| Long Beach Utilities Department | Los Angeles | 466,772 | Community | Purchased surface water |
| Santa Clarita Valley Water Agency | Los Angeles | 294,090 | Community | Surface water |
| Gswc - Southwest | Los Angeles | 277,740 | Community | Purchased surface water |
| San Gabriel Valley Water Co.-El Monte | Los Angeles | 248,000 | Community | Groundwater |
| Los Angeles Cwwd 40 Reg 4 & 34 Lancaster | Los Angeles | 208,129 | 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, “Pomona - City, Water Dept., PWSID CA1910126, California”, https://aquacensus.com/water-systems/california/pomona-city-water-dept-ca1910126 (data as of October 1, 2026).