County · California
Tuolumne County, California: drinking water records
Explore EPA records for 50 community water systems across 14 ZIP codes in Tuolumne County, then find water-testing resources and available recent monitoring-station readings.
Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages
Drinking-water records
EPA survey and compliance records are historical reports. UCMR 5 results are available for 5 of the 50 listed systems in this snapshot. A system with no reported PFAS detection is not a test of every tap or every contaminant.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems in this county
All 50 active community systems in the available county records, sorted by record completeness. Scroll the table to explore more systems.
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Groveland Community Serv Dist CA5510009 | 3,400 | 360 | 2 | 3 | 0 ppbbelow the action level |
| Tud - Upper Basin Water System CA5510012 | 13,280 | 360 | 0 | 0 | 0 ppbbelow the action level |
| Tud - Sonora/Jamestown Water System CA5510001 | 11,054 | 120 | 0 | 0 | 0 ppbbelow the action level |
| Tud - Columbia Water System CA5510013 | 5,463 | 240 | 0 | 0 | 4.7 ppbbelow the action level |
| Cdcr - Sierra Conservation Center CA5510851 | 3,571 | 0 | 0 | 4 | 0 ppbbelow the action level |
| Lake Don Pedro CSD CA5510008 | 3,240 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Pinecrest Permittees Assn CA5510004 | 1,298 | 0 | 0 | 1 | 12.1 ppbbelow the action level |
| Del Oro Water Company - Strawberry Div. CA5510007 | 1,295 | 0 | 0 | 2 | 0.9 ppbbelow the action level |
| Sonora Meadows Mutual Wtr Co CA5510023 | 1,123 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Leisure Pines Mutual Water Co CA5500053 | 340 | 0 | 0 | 1 | 12.6 ppbbelow the action level |
| Peppermint Creek MHP CA5500116 | 280 | 0 | 0 | 2 | 0 ppbbelow the action level |
| Twain Harte Valley Mwc CA5500080 | 202 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Alpine Acres Mutual Water Co CA5500041 | 195 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Cal Fire Baseline Conservation Camp CA5510852 | 150 | 0 | 0 | 6 | 0 ppbbelow the action level |
| Tud-Wards Ferry Ranches CA5500363 | 62 | 60 | 3 | 0 | 0 ppbbelow the action level |
| Ponderosa Mobile Home Park CA5500092 | 52 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Sierra Village Mobile Home Park CA5500353 | 22 | 0 | 0 | 1 | 2.6 ppbbelow the action level |
| Twain Harte Community Services District CA5510005 | 2,378 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Mi Wuk Village Mut Wtr Co CA5510006 | 2,163 | 0 | 0 | 0 | 12 ppbbelow the action level |
| Cold Springs Water Co CA5510011 | 1,771 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Tud - Ponderosa CA5510002 | 1,767 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Tud - Tuolumne Water System CA5510003 | 1,761 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Phoenix Lake Estates Cc Mwc CA5510026 | 1,168 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sonora Water Resources, INC CA5510024 | 1,154 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Don Pedro Rec Ag:flem.Meadows CA5500048 | 1,041 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Tud-Apple Valley Estates CA5510028 | 826 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Belleview Oaks Mutual Water Co CA5500042 | 468 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Mi Wuk Heights Mwc CA5500060 | 445 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Slide Inn Snowbowl Water Co CA5500077 | 417 | 0 | 0 | 0 | 3.3 ppbbelow the action level |
| Sierra Park Water Company INC. CA5510016 | 400 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sierra Village Mutual Water Co CA5500074 | 361 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Cascade Estates CA5500104 | 316 | 0 | 0 | 0 | 7.6 ppbbelow the action level |
| Bluebell Valley Mwc CA5500040 | 282 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Rawhide Mutual Water Company CA5500071 | 269 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sonora Estates Mobile Home Park CA5500086 | 235 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Tamarron Mobile Home Park CA5500193 | 225 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sugar Pine RV Resort CA5500115 | 219 | 0 | 0 | 0 | 9 ppbbelow the action level |
| Golden Sierra Estates_fka Mother Lode CA5500125 | 210 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Muller Mutual Water Company CA5500064 | 154 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sierra Twain Harte MHP CA5500096 | 129 | 0 | 0 | 0 | 0 ppbbelow the action level |
| 49er Trailer Ranch CA5500120 | 115 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Mono Vista Ranch MHP CA5500124 | 105 | 0 | 0 | 0 | 4 ppbbelow the action level |
| Long Barn Property Owners CA5500057 | 97 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Tud-Peaceful Pines Water System CA5510021 | 92 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Columbia Mobile Home Park CA5500149 | 89 | 0 | 0 | 0 | 4.4 ppbbelow the action level |
| Yosemite Vista Estates CA5500119 | 85 | 0 | 0 | 0 | 6.6 ppbbelow the action level |
| Rambling Hills Estates CA5500243 | 78 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Gold Rush Mobile Home Park CA5500128 | 67 | 0 | 0 | 0 | 11.7 ppbbelow the action level |
| Yosemite Nps-Hodgdon Meadow CA5510503 | 51 | 0 | 0 | 0 | 4.7 ppbbelow the action level |
| Tuolumne Me-Wuk Ridgeline 090605169 | 30 | 0 | 0 | 0 | 5 ppbbelow the action level |
USGS · Monitoring stations
The water, more recently.
Available station readings in Tuolumne County, California. Each measurement keeps its time, unit and original source.
These readings describe water at a monitoring station. They do not test your tap, measure PFAS or lead, or determine whether water is safe to drink or swim in.
Recent observations load when this section comes into view.
How these readings update
We check for updates every 10 minutes while this section is visible and show supported observations from the last 48 hours. The time beside a reading is when USGS measured it; the checked time is when our service retrieved the response. We mark a reading more than 6 hours old as older. Provisional observations can change after USGS review. A missing reading does not mean zero or clean water.
Temperature, pH, dissolved oxygen, turbidity, conductivity, streamflow and water level are shown only where a station reports them. Different measurements have different units and sampling intervals. USGS data and documentation.
Your next step
Water testing, reports & local help.
Use these official directories to find your drinking-water agency, a certified laboratory and public water records. We have not yet added an individually reviewed local resource list for this county.
Official national directories
Water testing
Find your state’s private-well program
EPA’s state directory points well owners to local program information. Services and eligibility vary by state and county.
Water testing
Find a certified drinking-water laboratory
Use EPA’s directory to reach your state’s laboratory certification program. EPA does not provide on-request testing of residential drinking water.
Public records
Find your utility’s Consumer Confidence Report
EPA links to community water-system reports and explains how to read them. Look for your actual supplier rather than assuming every address in a county shares one system.
Public records
Explore USGS water observations
Find current and historical observations from USGS monitoring locations, including available stream, lake, and groundwater data. Measurements vary by station and do not replace a test of your household water.
A county overview cannot identify every property’s water provider. If you use a public water system, confirm its name on your bill and request its annual Consumer Confidence Report. Private wells need their own testing; public-system records do not describe a private well.
Understand water testing and laboratory reportsResource descriptions are compiled by Tap Water Lookup. Review dates describe our source check, not a new water sample. How we review sources · Suggest a correction
Explore your area
Local coverage in Tuolumne County
14ZIP areas in this overview
Explore the water-system records, recent station readings and testing resources on this county page. They describe the systems and stations identified in each section; they are not a separate water test for every community.
Towns and communities
- Chinese Camp
- Columbia
- Groveland
- Jamestown
- Lake Don Pedro
- Long Barn
- Mi-Wuk Village
- Phoenix Lake
- Pine Mountain Lake
- Soulsbyville
- Strawberry
- Tuolumne City
- Twain Harte
View ZIP areas and understand coverage
- 95305Groveland
- 95309Chinese Camp
- 95310Columbia
- 95321Pine Mountain Lake
- 95327Jamestown
- 95329Lake Don Pedro
- 95335Long Barn
- 95346Mi-Wuk Village
- 95364
- 95370Phoenix Lake
- 95372Soulsbyville
- 95375Strawberry
- 95379Tuolumne City
- 95383Twain Harte
These Census ZIP Code Tabulation Areas are grouped here by their largest county overlap. A ZIP area can cross county lines and contain several water suppliers or private wells. Place labels reflect Census geography, not verified postal city names or utility service boundaries.
Records for these areas are currently presented in this county overview rather than individual ZIP reports. An unpublished report does not mean there are no water records. Confirm your supplier on your water bill; if you use a private well, testing your own well is the relevant next step.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Database prepared 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.
Compiled by Tap Water Lookup from the sources identified on this page. Read the methodology and review process.