Public water system · CA2400114
ActiveLake Yosemite County Park
At a glance
Lake Yosemite County Park (PWSID CA2400114) is an active transient non-community water system in Merced County, California. It reports serving 1,200 people through 24 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,200
Service connections
24
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Lake Yosemite County Park compare with other water systems in Merced County?
By EPA's size categories, Lake Yosemite County Park is a small system (501 to 3,300 people). Merced County has 120 active public water systems. Its population served is about half of the county average of 2,228 people per system, and accounts for 0.4% of the 267,324 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Lake Yosemite County Park is about 8.3 times that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. California has 3,016 active transient non-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 Lake Yosemite County Park?
EPA lists Lake Yosemite County Park 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. 30 of the 120 active systems in Merced County (25%) are also owned by a local government.
Does Lake Yosemite County Park have drinking water violations?
EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016. The violations listed here began between June 1996 and January 2016. By type: 7 contaminant level above the legal limit and 2 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (8 of them). EPA lists 9 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 |
|---|---|---|---|---|
| 2016-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2012-01-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2011-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1999-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
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.
Lake Yosemite County Park: frequently asked questions
Who runs Lake Yosemite County Park?
Lake Yosemite County Park (PWSID CA2400114) is a transient non-community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Lake Yosemite County Park serve?
Lake Yosemite County Park reports serving 1,200 people through 24 service connections in Merced County, California.
Where does Lake Yosemite County Park 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 Lake Yosemite County Park have any drinking water violations?
EPA's records list 9 violations for this system; 7 are health-based, and the most recent began in January 2016. 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 Lake Yosemite County 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 9 violations for this system; 7 are health-based, and the most recent began in January 2016. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Lake Yosemite County Park's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Lake Yosemite County Park is a 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 Merced County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Merced | Merced | 93,692 | Community | Groundwater |
| City of Los Banos | Merced | 47,419 | Community | Groundwater |
| City of Atwater | Merced | 29,479 | Community | Groundwater |
| City of Livingston | Merced | 14,894 | Community | Groundwater |
| Winton Water & Sanitary Dist | Merced | 9,745 | Community | Groundwater |
| Delhi Cwd | Merced | 7,784 | Community | Groundwater |
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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, “Lake Yosemite County Park, PWSID CA2400114, California”, https://aquacensus.com/water-systems/california/lake-yosemite-county-park-ca2400114 (data as of October 1, 2026).