Public water system · CA4110018
ActiveCity of Millbrae
At a glance
City of Millbrae (PWSID CA4110018) is an active community water system in San Mateo County, California. It reports serving 22,795 people through 6,767 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's Safe Drinking Water Act records list no violations for this system.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
22,795
Service connections
6,767
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does City of Millbrae compare with other water systems in San Mateo County?
By EPA's size categories, City of Millbrae is a large system (10,001 to 100,000 people). San Mateo County has 51 active public water systems. Its population served is about 48% above the county average of 15,363 people per system, and accounts for 2.9% of the 783,522 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 Millbrae is about 3.4 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 City of Millbrae?
EPA lists City of Millbrae 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. 19 of the 51 active systems in San Mateo County (37%) are also owned by a local government.
Does City of Millbrae have drinking water violations?
No SDWA violations on record.
EPA's SDWA violation and enforcement data (via EPA ECHO, updated quarterly) lists no violations for City of Millbrae. For the latest compliance status, check EPA ECHO for current compliance history.
City of Millbrae: frequently asked questions
Who runs City of Millbrae?
City of Millbrae (PWSID CA4110018) 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 Millbrae serve?
City of Millbrae reports serving 22,795 people through 6,767 service connections in San Mateo County, California.
Where does City of Millbrae 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 City of Millbrae have any drinking water violations?
EPA's Safe Drinking Water Act records list no violations for this system.
Is City of Millbrae'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 Safe Drinking Water Act records list no violations for this system. 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 Millbrae's water quality report?
As a community water system, City of Millbrae 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 Mateo County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Daly City | San Mateo | 104,901 | Community | Purchased surface water |
| California Water Service - San Mateo | San Mateo | 102,348 | Community | Purchased surface water |
| City of Redwood City | San Mateo | 92,819 | Community | Purchased surface water |
| California Water Service-S San Francisco | San Mateo | 64,146 | Community | Purchased surface water |
| California Water Service - Bear Gulch | San Mateo | 61,431 | Community | Surface water |
| City of San Bruno | San Mateo | 42,631 | Community | Purchased surface water |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “City of Millbrae, PWSID CA4110018, California”, https://aquacensus.com/water-systems/california/city-of-millbrae-ca4110018 (data as of October 1, 2026).