Public water system · CA4000808
ActiveMonte Sereno Mutual Benefit Water
At a glance
Monte Sereno Mutual Benefit Water (PWSID CA4000808) is an active community water system in San Luis Obispo County, California. It reports serving 65 people through 26 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's Safe Drinking Water Act records list no violations for this system.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
65
Service connections
26
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Monte Sereno Mutual Benefit Water compare with other water systems in San Luis Obispo County?
By EPA's size categories, Monte Sereno Mutual Benefit Water is a very small system (500 people or fewer). 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 less than 0.1% 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 Monte Sereno Mutual Benefit Water 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 Monte Sereno Mutual Benefit Water?
EPA lists Monte Sereno Mutual Benefit Water 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 Monte Sereno Mutual Benefit Water have drinking water violations?
No SDWA violations on record.
EPA's SDWA violation and enforcement data (via EPA ECHO, updated quarterly) lists no violations for Monte Sereno Mutual Benefit Water. For the latest compliance status, check EPA ECHO for current compliance history.
Monte Sereno Mutual Benefit Water: frequently asked questions
Who runs Monte Sereno Mutual Benefit Water?
Monte Sereno Mutual Benefit Water (PWSID CA4000808) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Monte Sereno Mutual Benefit Water serve?
Monte Sereno Mutual Benefit Water reports serving 65 people through 26 service connections in San Luis Obispo County, California.
Where does Monte Sereno Mutual Benefit Water 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 Monte Sereno Mutual Benefit Water have any drinking water violations?
EPA's Safe Drinking Water Act records list no violations for this system.
Is Monte Sereno Mutual Benefit Water'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 Safe Drinking Water Act records list no violations for this system. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Monte Sereno Mutual Benefit Water's water quality report?
As a community water system, Monte Sereno Mutual Benefit Water 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, “Monte Sereno Mutual Benefit Water, PWSID CA4000808, California”, https://aquacensus.com/water-systems/california/monte-sereno-mutual-benefit-water-ca4000808 (data as of October 1, 2026).