Public water system · CA4000650
ActiveMesa Dunes Mobile Home Estates
At a glance
Mesa Dunes Mobile Home Estates (PWSID CA4000650) is an active community water system in San Luis Obispo County, California. It reports serving 600 people through 313 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 9 violations for this system; none is health-based, and the most recent began in February 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
600
Service connections
313
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mesa Dunes Mobile Home Estates compare with other water systems in San Luis Obispo County?
By EPA's size categories, Mesa Dunes Mobile Home Estates is a small system (501 to 3,300 people). San Luis Obispo County has 171 active public water systems. Its population served is well below the county average of 2,038 people per system, and accounts for 0.2% 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 Mesa Dunes Mobile Home Estates 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. 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 Mesa Dunes Mobile Home Estates?
EPA lists Mesa Dunes Mobile Home Estates as privately owned. 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. 130 of the 171 active systems in San Luis Obispo County (76%) are also privately owned.
Does Mesa Dunes Mobile Home Estates have drinking water violations?
EPA's records list 9 violations for this system; none is health-based, and the most recent began in February 2021. The violations listed here began between October 1980 and February 2021. By type: 8 monitoring and reporting and 1 monitoring. The contaminant or rule involved most often is Haloacetic acids (HAA5) (2 of them). EPA lists 7 as resolved and 2 as archived. 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. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2021-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2014-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1981-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
| 1980-10-30 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 9 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.
Mesa Dunes Mobile Home Estates: frequently asked questions
Who runs Mesa Dunes Mobile Home Estates?
Mesa Dunes Mobile Home Estates (PWSID CA4000650) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Mesa Dunes Mobile Home Estates serve?
Mesa Dunes Mobile Home Estates reports serving 600 people through 313 service connections in San Luis Obispo County, California.
Where does Mesa Dunes Mobile Home Estates 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 Mesa Dunes Mobile Home Estates have any drinking water violations?
EPA's records list 9 violations for this system; none is health-based, and the most recent began in February 2021. 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 Mesa Dunes Mobile Home Estates' 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 9 violations for this system; none is health-based, and the most recent began in February 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Mesa Dunes Mobile Home Estates' water quality report?
As a community water system, Mesa Dunes Mobile Home Estates 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 |
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, “Mesa Dunes Mobile Home Estates, PWSID CA4000650, California”, https://aquacensus.com/water-systems/california/mesa-dunes-mobile-home-estates-ca4000650 (data as of October 1, 2026).