Public water system · CA2210923
ActiveYosemite Alpine Csd
At a glance
Yosemite Alpine Csd (PWSID CA2210923) is an active transient non-community water system in Mariposa County, California. It reports serving 38 people through 38 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in April 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
38
Service connections
38
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Yosemite Alpine Csd compare with other water systems in Mariposa County?
By EPA's size categories, Yosemite Alpine Csd is a very small system (500 people or fewer). Mariposa County has 67 active public water systems. Its population served is well below the county average of 381 people per system, and accounts for 0.1% of the 25,508 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 Yosemite Alpine Csd is well below 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 Yosemite Alpine Csd?
EPA lists Yosemite Alpine Csd 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. 33 of the 67 active systems in Mariposa County (49%) are also privately owned.
Does Yosemite Alpine Csd have drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in April 2025. The violations listed here began between January 1996 and April 2025. By type: 3 monitoring and reporting, 2 contaminant level above the legal limit and 1 monitoring. The contaminant or rule involved most often is Nitrate (2 of them). EPA lists 6 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 |
|---|---|---|---|---|
| 2025-04-01 | MonitoringMonitoring, Lab Certification/Method Error (RTCR) · code 3D | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2001-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1996-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-01-02 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
All 6 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.
Yosemite Alpine Csd: frequently asked questions
Who runs Yosemite Alpine Csd?
Yosemite Alpine Csd (PWSID CA2210923) is a transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Yosemite Alpine Csd serve?
Yosemite Alpine Csd reports serving 38 people through 38 service connections in Mariposa County, California.
Where does Yosemite Alpine Csd 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 Yosemite Alpine Csd have any drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in April 2025. 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 Yosemite Alpine Csd'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 6 violations for this system; 2 are health-based, and the most recent began in April 2025. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Yosemite Alpine Csd's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Yosemite Alpine Csd 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 Mariposa County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Yosemite Nps-Glacier Point | Mariposa | 4,000 | Transient non-community | Surface water |
| Blm-Briceburg Water System | Mariposa | 3,196 | Transient non-community | Groundwater |
| Mariposa Public Utility Dist | Mariposa | 2,000 | Community | Surface water |
| Yosemite Nps-Bridalveil Fall | Mariposa | 1,163 | Transient non-community | Groundwater |
| Mid - Mc Swain Rec Area | Mariposa | 1,119 | Transient non-community | Surface water |
| Yosemite Nps-Yosemite Valley | Mariposa | 1,000 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Yosemite Alpine Csd, PWSID CA2210923, California”, https://aquacensus.com/water-systems/california/yosemite-alpine-csd-ca2210923 (data as of October 1, 2026).