Public water system · CA1900571
ActiveUsfs-Chilao Main A-9
At a glance
Usfs-Chilao Main A-9 (PWSID CA1900571) is an active transient non-community water system in Los Angeles County, California. It reports serving 50 people through 5 service connections. Its primary water source is groundwater, and EPA lists it as owned by the federal government. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2019.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
50
Service connections
5
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Usfs-Chilao Main A-9 compare with other water systems in Los Angeles County?
By EPA's size categories, Usfs-Chilao Main A-9 is a very small system (500 people or fewer). Los Angeles County has 275 active public water systems. Its population served is well below the county average of 36,762 people per system, and accounts for less than 0.1% 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 transient non-community water system reports serving 144 people, so Usfs-Chilao Main A-9 is about 65% below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. California has 3,016 active transient non-community water systems, 40% 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 Usfs-Chilao Main A-9?
EPA lists Usfs-Chilao Main A-9 as owned by the federal 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 275 active systems in Los Angeles County (6.9%) are also owned by the federal government.
Does Usfs-Chilao Main A-9 have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2019. The violations listed here began between March 1984 and January 2019. By type: 7 public notice, recordkeeping or other, 2 monitoring and reporting, 2 contaminant level above the legal limit and 1 monitoring. The contaminant or rule involved most often is Revised Total Coliform Rule (2 of them). EPA lists 7 as archived and 5 as resolved. 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. 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 |
|---|---|---|---|---|
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2017-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2016-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2011-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1984-09-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-08-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-07-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-06-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-05-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-04-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1984-03-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
The 12 most recent 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.
Usfs-Chilao Main A-9: frequently asked questions
Who runs Usfs-Chilao Main A-9?
Usfs-Chilao Main A-9 (PWSID CA1900571) is a transient non-community water system owned by the federal government. It is regulated by the CA state drinking water program.
How many people does Usfs-Chilao Main A-9 serve?
Usfs-Chilao Main A-9 reports serving 50 people through 5 service connections in Los Angeles County, California.
Where does Usfs-Chilao Main A-9 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 Usfs-Chilao Main A-9 have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2019. 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 Usfs-Chilao Main A-9'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. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2019. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Usfs-Chilao Main A-9's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Usfs-Chilao Main A-9 is a 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 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 |
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, “Usfs-Chilao Main A-9, PWSID CA1900571, California”, https://aquacensus.com/water-systems/california/usfs-chilao-main-a-9-ca1900571 (data as of October 1, 2026).