Public water system · CA3901248
ActiveFlag City Water System
At a glance
Flag City Water System (PWSID CA3901248) is an active non-transient non-community water system in San Joaquin County, California. It reports serving 135 people through 41 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2006.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
135
Service connections
41
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Flag City Water System compare with other water systems in San Joaquin County?
By EPA's size categories, Flag City Water System is a very small system (500 people or fewer). San Joaquin County has 302 active public water systems. Its population served is well below the county average of 2,571 people per system, and accounts for less than 0.1% of the 776,334 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active non-transient non-community water system reports serving 430 people, so Flag City Water System is well below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. California has 1,466 active non-transient non-community water systems, 20% of the state's 7,479 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,179 California systems (83%) list groundwater as their primary source.
Who owns and regulates Flag City Water System?
EPA lists Flag City Water System 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. 69 of the 302 active systems in San Joaquin County (23%) are also owned by a local government.
Does Flag City Water System have drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2006. The violations listed here began between April 2000 and July 2006. By type: 2 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Consumer Confidence Rule (2 of them). EPA lists 3 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 |
|---|---|---|---|---|
| 2006-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2002-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2000-04-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
All 3 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.
Flag City Water System: frequently asked questions
Who runs Flag City Water System?
Flag City Water System (PWSID CA3901248) is a non-transient non-community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Flag City Water System serve?
Flag City Water System reports serving 135 people through 41 service connections in San Joaquin County, California.
Where does Flag City Water System get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Flag City Water System have any drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2006. 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 Flag City Water System'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 3 violations for this system; none is health-based, and the most recent began in July 2006. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Flag City Water System's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Flag City Water System is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in San Joaquin County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Stockton | San Joaquin | 191,302 | Community | Surface water |
| California Water Service - Stockton | San Joaquin | 176,266 | Community | Purchased surface water |
| Tracy, City of | San Joaquin | 96,609 | Community | Surface water |
| Manteca, City of | San Joaquin | 84,928 | Community | Purchased surface water |
| Lodi, City of | San Joaquin | 68,272 | Community | Surface water |
| City of Lathrop | San Joaquin | 35,080 | 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, “Flag City Water System, PWSID CA3901248, California”, https://aquacensus.com/water-systems/california/flag-city-water-system-ca3901248 (data as of October 1, 2026).