Public water system · CA4000648
ActiveKen Mar Gardens
At a glance
Ken Mar Gardens (PWSID CA4000648) is an active community water system in San Luis Obispo County, California. It reports serving 84 people through 49 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
84
Service connections
49
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Ken Mar Gardens compare with other water systems in San Luis Obispo County?
By EPA's size categories, Ken Mar Gardens 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 Ken Mar Gardens 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 Ken Mar Gardens?
EPA lists Ken Mar Gardens 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 Ken Mar Gardens have drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2026. The violations listed here began between July 2023 and January 2026. By type: 12 contaminant level above the legal limit. The contaminant or rule involved most often is Selenium (11 of them). EPA lists 11 as archived and 1 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 |
|---|---|---|---|---|
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2024-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Nitratecode 1040 | Yes | Resolved |
| 2023-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | Archived |
| 2023-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Seleniumcode 1045 | Yes | 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.
Ken Mar Gardens: frequently asked questions
Who runs Ken Mar Gardens?
Ken Mar Gardens (PWSID CA4000648) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Ken Mar Gardens serve?
Ken Mar Gardens reports serving 84 people through 49 service connections in San Luis Obispo County, California.
Where does Ken Mar Gardens 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 Ken Mar Gardens have any drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in January 2026. 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 Ken Mar Gardens' 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, 12 are health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Ken Mar Gardens' water quality report?
As a community water system, Ken Mar Gardens 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, “Ken Mar Gardens, PWSID CA4000648, California”, https://aquacensus.com/water-systems/california/ken-mar-gardens-ca4000648 (data as of October 1, 2026).