Public water system · CA4010300
ActiveHearst Monument State Park
At a glance
Hearst Monument State Park (PWSID CA4010300) is an active non-transient non-community water system in San Luis Obispo County, California. It reports serving 200 people through 16 service connections. Its primary water source is surface water, and EPA lists it as owned by a state government. EPA's records list 5 violations for this system; 2 are health-based, and the most recent began in January 2017.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
200
Service connections
16
Primary source
SW
Surface water
System type
NTNCWS
Non-transient non-community water system
System record
How does Hearst Monument State Park compare with other water systems in San Luis Obispo County?
By EPA's size categories, Hearst Monument State Park 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 Hearst Monument State Park is about half of 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. 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 Hearst Monument State Park?
EPA lists Hearst Monument State Park as owned by a state 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. 6 of the 171 active systems in San Luis Obispo County (3.5%) are also owned by a state government.
Does Hearst Monument State Park have drinking water violations?
EPA's records list 5 violations for this system; 2 are health-based, and the most recent began in January 2017. The violations listed here began between July 1993 and January 2017. By type: 3 monitoring and reporting and 2 required treatment not met. The contaminant or rule involved most often is Surface Water Treatment Rule (2 of them). EPA lists 5 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 |
|---|---|---|---|---|
| 2017-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 1996-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1993-07-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
All 5 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.
Hearst Monument State Park: frequently asked questions
Who runs Hearst Monument State Park?
Hearst Monument State Park (PWSID CA4010300) is a non-transient non-community water system owned by a state government. It is regulated by the CA state drinking water program.
How many people does Hearst Monument State Park serve?
Hearst Monument State Park reports serving 200 people through 16 service connections in San Luis Obispo County, California.
Where does Hearst Monument State Park 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 Hearst Monument State Park have any drinking water violations?
EPA's records list 5 violations for this system; 2 are health-based, and the most recent began in January 2017. 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 Hearst Monument State Park'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 5 violations for this system; 2 are health-based, and the most recent began in January 2017. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Hearst Monument State Park's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Hearst Monument State Park 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, “Hearst Monument State Park, PWSID CA4010300, California”, https://aquacensus.com/water-systems/california/hearst-monument-state-park-ca4010300 (data as of October 1, 2026).