Public water system · CA4000732
ActiveCarrisa Plains Elementary
At a glance
Carrisa Plains Elementary (PWSID CA4000732) is an active non-transient non-community water system in San Luis Obispo County, California. It reports serving 40 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as owned by a local government. 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
40
Service connections
1
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Carrisa Plains Elementary compare with other water systems in San Luis Obispo County?
By EPA's size categories, Carrisa Plains Elementary 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 non-transient non-community water system reports serving 430 people, so Carrisa Plains Elementary is well 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. 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 Carrisa Plains Elementary?
EPA lists Carrisa Plains Elementary 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 Carrisa Plains Elementary 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 April 2023 and January 2026. By type: 12 contaminant level above the legal limit. The contaminant or rule involved most often is Nitrate (12 of them). EPA lists 12 as archived. 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 |
|---|---|---|---|---|
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2023-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2023-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | Yes | Archived |
| 2023-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitratecode 1040 | 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.
Carrisa Plains Elementary: frequently asked questions
Who runs Carrisa Plains Elementary?
Carrisa Plains Elementary (PWSID CA4000732) is a non-transient non-community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Carrisa Plains Elementary serve?
Carrisa Plains Elementary reports serving 40 people through 1 service connection in San Luis Obispo County, California.
Where does Carrisa Plains Elementary 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 Carrisa Plains Elementary 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 Carrisa Plains Elementary'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, 12 are health-based, and the most recent began in January 2026. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Carrisa Plains Elementary's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Carrisa Plains Elementary 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 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, “Carrisa Plains Elementary, PWSID CA4000732, California”, https://aquacensus.com/water-systems/california/carrisa-plains-elementary-ca4000732 (data as of October 1, 2026).