Mariposa County, California — public water systems
At a glance
67 active public water systems are filed under Mariposa County, California in EPA's SDWIS records, together reporting 25,508 people served. The largest is Yosemite Nps-Glacier Point, which reports serving 4,000 people. 11 are community water systems serving people where they live; the other 56 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.
Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.
Active systems
67
Population served
25.5K
Community systems
11
Groundwater share
86.6%
How does Mariposa County compare with other California counties?
Mariposa County has the 39th-most active public water systems among the 201 counties listed for active California systems in EPA records; among the 72 with 3 or more systems, the median has 73. Its systems report 25,508 people served in total, the 54th-largest county figure in the state and less than 0.1% of the statewide total. The average system here reports serving 381 people, well below the California average of 5,706. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.
Where does Mariposa County's drinking water come from?
By primary water source, Mariposa County's active systems draw on groundwater (58, 87%), surface water (8, 12%) and purchased surface water (1, 1.5%). Overall, 87% rely mainly on groundwater (including purchased groundwater) and 13% on surface water, compared with 85% and 15% across California. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Yosemite Nps-Glacier Point, draws primarily on surface water.
What kinds of water systems operate in Mariposa County?
Mariposa County's active systems break down as 11 community systems (16%), 9 non-transient non-community systems (13%) and 47 transient non-community systems (70%). 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. 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. 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. EPA lists their owner types as private (49%), local government (31%) and federal government (19%).
The 50 largest water systems in Mariposa County
🔒 Create a free account to export CSV| # | Water system | County | Population served | Type | Source |
|---|---|---|---|---|---|
| 1 | Yosemite Nps-Glacier Point | Mariposa | 4,000 | Transient non-community | Surface water |
| 2 | Blm-Briceburg Water System | Mariposa | 3,196 | Transient non-community | Groundwater |
| 3 | Mariposa Public Utility Dist | Mariposa | 2,000 | Community | Surface water |
| 4 | Yosemite Nps-Bridalveil Fall | Mariposa | 1,163 | Transient non-community | Groundwater |
| 5 | Mid - Mc Swain Rec Area | Mariposa | 1,119 | Transient non-community | Surface water |
| 6 | Yosemite Nps-Badger Pass | Mariposa | 1,000 | Transient non-community | Groundwater |
| 7 | Yosemite Nps-Yosemite Valley | Mariposa | 1,000 | Community | Groundwater |
| 8 | Delaware North Parks Services at Tenaya | Mariposa | 800 | Non-transient non-community | Groundwater |
| 9 | Ponderosa Basin Mutual Wtr Co | Mariposa | 798 | Community | Groundwater |
| 10 | Yosemite View Lodge | Mariposa | 750 | Non-transient non-community | Groundwater |
| 11 | Cedar Lodge | Mariposa | 656 | Community | Groundwater |
| 12 | Yosemite Nps-El Portal | Mariposa | 635 | Community | Groundwater |
| 13 | Yosemite Nps-Crane Flat | Mariposa | 500 | Transient non-community | Groundwater |
| 14 | Mid - Mc Clure Point Rec Area | Mariposa | 470 | Transient non-community | Surface water |
| 15 | Mcusd - Woodland Elementary School | Mariposa | 466 | Non-transient non-community | Groundwater |
| 16 | Yosemite Nps-Bridalveil Creek Cg | Mariposa | 450 | Transient non-community | Groundwater |
| 17 | Yosemite West Water System | Mariposa | 420 | Community | Groundwater |
| 18 | Mid - Barrett Cove | Mariposa | 407 | Transient non-community | Groundwater |
| 19 | Yosemite Nps-May Lake Camp | Mariposa | 300 | Transient non-community | Surface water |
| 20 | Autocamp-Yosemite | Mariposa | 290 | Transient non-community | Groundwater |
| 21 | Mcclure Boat Club, Inc.. | Mariposa | 286 | Community | Surface water |
| 22 | Mariposa Pines Mutual | Mariposa | 284 | Community | Groundwater |
| 23 | The Cottages at Tenaya Lodge | Mariposa | 265 | Transient non-community | Groundwater |
| 24 | Mcpr-Cathey S Valley Park | Mariposa | 250 | Transient non-community | Groundwater |
| 25 | Fishcamp Mutual Water Company | Mariposa | 239 | Transient non-community | Groundwater |
| 26 | Camp Wawona | Mariposa | 222 | Transient non-community | Groundwater |
| 27 | Yosemite Nps-Arch Rock | Mariposa | 200 | Transient non-community | Groundwater |
| 28 | Mariposa District Fairground | Mariposa | 200 | Transient non-community | Groundwater |
| 29 | New Life Calvary Chapel of Mariposa | Mariposa | 200 | Transient non-community | Groundwater |
| 30 | Mpwd-Coulterville Csa 1 | Mariposa | 193 | Community | Groundwater |
| 31 | Summerdale Campground | Mariposa | 175 | Transient non-community | Groundwater |
| 32 | Mcusd - Sierra Foothill Charter School | Mariposa | 157 | Non-transient non-community | Purchased surface water |
| 33 | Yosemite Nps-Sunrise Hi | Mariposa | 150 | Transient non-community | Surface water |
| 34 | Yosemite Nps-Wawona | Mariposa | 150 | Community | Surface water |
| 35 | Mid -Horseshoe Bend Rec Area | Mariposa | 142 | Transient non-community | Groundwater |
| 36 | Mcusd - Mariposa Junior High School | Mariposa | 134 | Non-transient non-community | Groundwater |
| 37 | Yosemite Terrace Estates | Mariposa | 130 | Community | Groundwater |
| 38 | Yosemite Bug Hostel | Mariposa | 122 | Transient non-community | Groundwater |
| 39 | Green Meadows Outdoor School | Mariposa | 119 | Transient non-community | Groundwater |
| 40 | Wildhaven Yosemite Water System | Mariposa | 100 | Transient non-community | Groundwater |
| 41 | Redwoods Main Water System | Mariposa | 93 | Transient non-community | Groundwater |
| 42 | Mid - Bagby Recreation Area | Mariposa | 85 | Transient non-community | Groundwater |
| 43 | North Wawona Estates (B System) | Mariposa | 81 | Transient non-community | Groundwater |
| 44 | White Chief Mountain Lodge | Mariposa | 73 | Transient non-community | Groundwater |
| 45 | LDS Church Mariposa | Mariposa | 65 | Transient non-community | Groundwater |
| 46 | Yosemite'S Scenic Wonders | Mariposa | 65 | Transient non-community | Groundwater |
| 47 | Wampum Hill Trailer Village | Mariposa | 62 | Transient non-community | Groundwater |
| 48 | Shore Fun R.V. Park | Mariposa | 60 | Transient non-community | Groundwater |
| 49 | Mariposa Industrial Park Water Company | Mariposa | 60 | Transient non-community | Groundwater |
| 50 | Yosemite Ridge Resort | Mariposa | 60 | Transient non-community | Groundwater |
All other water systems in Mariposa County (17)
The remaining active systems filed under Mariposa County, largest first, with the population each reports serving.
- Outward Bound California56
- Mariposa County Public Works Department55
- Mcusd -Coulterville-Greeley Hill School55
- Tavis Corporation50
- Mcpr-Midpines Park50
- Mcpr - Darrah School Park50
- Yosemite Alpine Csd38
- Redwoods 70'S Water System36
- Yosemite Resort Properties36
- Mcpr- Woodland Park35
- Camp Chilnualna Water System34
- Whispering Pines Apartments32
- Buck Meadows Lodge-Yosemite Westgate31
- Savages Trading Post30
- North Wawona Park Mutual (A System)28
- Mcpr-Hornitos Co. Park25
- Mcpr-Red Cloud Park25
Mariposa County water systems: frequently asked questions
How many public water systems are in Mariposa County, California?
EPA's SDWIS records file 67 active public water systems under Mariposa County, California: 11 community systems (16%), 9 non-transient non-community systems (13%) and 47 transient non-community systems (70%).
Who supplies drinking water in Mariposa County, CA?
The largest community water systems filed under Mariposa County are Mariposa Public Utility Dist (2,000 people served), Yosemite Nps-Yosemite Valley (1,000 people served) and Ponderosa Basin Mutual Wtr Co (798 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.
Does Mariposa County's drinking water come from groundwater or surface water?
Of the 67 active public water systems in Mariposa County, 87% draw mainly on groundwater and 13% on surface water, counting purchased supplies. The largest system, Yosemite Nps-Glacier Point, uses surface water.
Where can I find a water quality report for Mariposa County?
Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 11 community systems are filed under Mariposa County, so the report to look for is the one from the system that supplies your address.
How can I check violations for a water system in Mariposa County?
Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.
More California water systems
- All California public water systems· 7,479 active
- Lake County· 81 systems
- Imperial County· 76 systems
- Siskiyou County· 69 systems
- Amador County· 67 systems
- San Benito County· 63 systems
- Solano County· 63 systems
- How to find out who supplies your drinking water
- How to find and read your annual water quality report
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, “Public water systems in Mariposa County, California”, https://aquacensus.com/water-systems/california/mariposa (data as of October 1, 2026).