Public water system · CA4010022
ActiveLopez Project
At a glance
Lopez Project (PWSID CA4010022) is an active community water system in San Luis Obispo County, California. It reports serving 1,569 people through 31 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in April 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,569
Service connections
31
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Lopez Project compare with other water systems in San Luis Obispo County?
By EPA's size categories, Lopez Project is a small system (501 to 3,300 people). San Luis Obispo County has 171 active public water systems. Its population served is about 23% below the county average of 2,038 people per system, and accounts for 0.5% of the 348,510 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 Lopez Project is well below 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 Lopez Project?
EPA lists Lopez Project 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. 33 of the 171 active systems in San Luis Obispo County (19%) are also owned by a local government.
Does Lopez Project have drinking water violations?
EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in April 2025. The violations listed here began between July 1993 and April 2025. By type: 2 contaminant level above the legal limit and 1 monitoring and reporting. The contaminants or rules involved are Revised Total Coliform Rule, Total coliform bacteria (TCR) and Lead and Copper Rule. 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 |
|---|---|---|---|---|
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2008-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | 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 |
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.
Lopez Project: frequently asked questions
Who runs Lopez Project?
Lopez Project (PWSID CA4010022) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Lopez Project serve?
Lopez Project reports serving 1,569 people through 31 service connections in San Luis Obispo County, California.
Where does Lopez Project 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 Lopez Project have any drinking water violations?
EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in April 2025. 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 Lopez Project'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; 2 are health-based, and the most recent began in April 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Lopez Project's water quality report?
As a community water system, Lopez Project 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 Luis Obispo County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Santa Margarita Recreation Area | San Luis Obispo | 50,001 | Transient non-community | Groundwater |
| San Luis Obispo Water Department | San Luis Obispo | 47,788 | Community | Surface water |
| City of Paso Robles Water Division | San Luis Obispo | 31,176 | Community | Surface water |
| Atascadero Mutual Water Co | San Luis Obispo | 30,618 | Community | Groundwater |
| City of Arroyo Grande Utilities Division | San Luis Obispo | 17,963 | Community | Purchased surface water |
| California Mens Colony | San Luis Obispo | 15,000 | Community | 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, “Lopez Project, PWSID CA4010022, California”, https://aquacensus.com/water-systems/california/lopez-project-ca4010022 (data as of October 1, 2026).