Public water system · CA2410950
ActiveDwr - San Luis Division O&M
At a glance
Dwr - San Luis Division O&M (PWSID CA2410950) is an active non-transient non-community water system in Merced County, California. It reports serving 150 people through 6 service connections. Its primary water source is surface water, and EPA lists it as owned by a state government. Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in July 2016.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
150
Service connections
6
Primary source
SW
Surface water
System type
NTNCWS
Non-transient non-community water system
System record
How does Dwr - San Luis Division O&M compare with other water systems in Merced County?
By EPA's size categories, Dwr - San Luis Division O&M is a very small system (500 people or fewer). Merced County has 120 active public water systems. Its population served is well below the county average of 2,228 people per system, and accounts for less than 0.1% of the 267,324 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 Dwr - San Luis Division O&M is about 65% 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. 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 Dwr - San Luis Division O&M?
EPA lists Dwr - San Luis Division O&M as owned by a state 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. 8 of the 120 active systems in Merced County (6.7%) are also owned by a state government.
Does Dwr - San Luis Division O&M have drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in July 2016. The violations listed here began between April 2010 and July 2016. By type: 9 contaminant level above the legal limit and 3 monitoring and reporting. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (9 of them). EPA lists 12 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 |
|---|---|---|---|---|
| 2016-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2016-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2016-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2016-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2014-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2014-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2012-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2011-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2010-08-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2010-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
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.
Dwr - San Luis Division O&M: frequently asked questions
Who runs Dwr - San Luis Division O&M?
Dwr - San Luis Division O&M (PWSID CA2410950) is a non-transient non-community water system owned by a state government. It is regulated by the CA state drinking water program.
How many people does Dwr - San Luis Division O&M serve?
Dwr - San Luis Division O&M reports serving 150 people through 6 service connections in Merced County, California.
Where does Dwr - San Luis Division O&M 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 Dwr - San Luis Division O&M have any drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in July 2016. 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 Dwr - San Luis Division O&M'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, 9 are health-based, and the most recent began in July 2016. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Dwr - San Luis Division O&M's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Dwr - San Luis Division O&M 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 Merced County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Merced | Merced | 93,692 | Community | Groundwater |
| City of Los Banos | Merced | 47,419 | Community | Groundwater |
| City of Atwater | Merced | 29,479 | Community | Groundwater |
| City of Livingston | Merced | 14,894 | Community | Groundwater |
| Winton Water & Sanitary Dist | Merced | 9,745 | Community | Groundwater |
| Delhi Cwd | Merced | 7,784 | Community | Groundwater |
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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, “Dwr - San Luis Division O&M, PWSID CA2410950, California”, https://aquacensus.com/water-systems/california/dwr-san-luis-division-o-m-ca2410950 (data as of October 1, 2026).