Tapcensus

California

Tuolumne County drinking water quality

120 active public water systems serve 76,382 people in Tuolumne County. 25 are compliant, 95 had at least one EPA violation in the past three years, 0 are designated serious violators, and 11 carry a health flag.

Active systems 120 49 community systems
People served 76K by public water systems
Systems with violations 95 79% of active systems, past 3 years
Serious violators 0 11 systems carry a health flag

Needs attention

Groveland Community Serv Dist CA5510009 · Community water system · Serves 3,400 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Lake Don Pedro Csd CA5510008 · Community water system · Serves 1,700 3 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Sonora Meadows Mutual Wtr CO CA5510023 · Community water system · Serves 1,123 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Leisure Pines Mutual Water CO CA5500053 · Community water system · Serves 340 3 rules violated in the past three years. Unresolved: Lead and Copper Rule and Lead and Copper Rule Revisions.
Twain Harte Valley Mwc CA5500080 · Community water system · Serves 202 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Cal Fire Baseline Conservation Camp CA5510852 · Community water system · Serves 150 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Ponderosa Mobile Home Park CA5500092 · Community water system · Serves 146 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Pinecrest Permittees Assn CA5510004 · Community water system · Serves 55 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Firefall Ranch Water System CA5500357 · Non-Transient non-community system · Serves 26 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Pinecrest Elementary School CA5500221 · Non-Transient non-community system · Serves 26 3 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.

1 more systems with a serious violator or health flag designation are in the lists below.

Community water systems

49 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Tud Upper Basin Water System
 13,331 1 0
Tud Sonora/jamestown Water System
 11,113 1 0
Tud Columbia Water System
 5,482 1 0
Cdcr Sierra Conservation Center
 3,571 0 0
Groveland Community Serv Dist
 3,400 2 1
Twain Harte Community Services District
 2,378 1 0
Tud Tuolumne Water System
Sonora 		1,798 1 0
Tud Ponderosa
 1,781 1 0
Cold Springs Water CO
 1,771 1 0
Lake Don Pedro Csd
 1,700 3 1
Phoenix Lake Estates CC Mwc
 1,168 1 0
Sonora Meadows Mutual Wtr CO
 1,123 2 1
MI Wuk Village Mut Wtr CO
 1,076 1 0
Tud-Apple Valley Estates
 829 1 0
Sonora Water Resources, INC
 785 0 0
Belleview Oaks Mutual Water CO
 468 1 0
MI Wuk Heights Mwc
 445 0 0
Slide Inn Snowbowl Water CO
 417 1 0
Del Oro Water Company Strawberry Div.
 386 1 0
Leisure Pines Mutual Water CO
 340 3 2
Cascade Estates
 316 1 0
Peppermint Creek MHP
 280 2 0
Rawhide Mutual Water Company
 269 1 0
Sierra Village Mutual Water CO
 264 1 0
Bluebell Valley Mwc
 252 1 0
Sonora Estates Mobile Home Park
 235 1 0
Tamarron Mobile Home Park
 225 1 0
Golden Sierra Estates_fka Mother Lode
 210 2 1
Twain Harte Valley Mwc
 202 2 1
Alpine Acres Mutual Water CO
 195 3 0
Sugar Pine RV Resort
 160 2 0
Muller Mutual Water Company
 154 1 0
Cal Fire Baseline Conservation Camp
 150 1 1
Ponderosa Mobile Home Park
 146 2 1
Sierra Twain Harte MHP
 129 1 0
Mono Vista Ranch MHP
 105 2 0
Sierra Park Water Company Inc.
 100 1 0
Long Barn Property Owners
 97 2 1
49er Trailer Ranch
 95 1 0
Tud-Peaceful Pines Water System
 92 1 0
Columbia Mobile Home Park
 89 1 0
Yosemite Vista Estates
 80 2 1
Rambling Hills Estates
 78 1 0
Gold Rush Mobile Home Park
 67 1 0
Tud-Wards Ferry Ranches
 62 1 0
Pinecrest Permittees Assn
 55 2 1
Yosemite Nps-Hodgdon Meadow
 51 2 1
Don Pedro Rec Ag:flem.meadows
 41 1 0
Sierra Village Mobile Home Park
 21 2 1
Non-community systems (71: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Peppery Bar and Grill, the
 4,500 1 0
Yosemite Nps-Tuolumne Meadows
 2,500 0 0
Usbr-Tuttletown Rec Area
 1,000 0 0
Usfs Clark Fork Campd
 612 1 0
Deloro Valley Water System
 528 2 0
Jenness Park Christian Camp
 508 1 0
Camp Tawonga
 505 1 0
Heavenly Hills Christian Camp
 504 1 0
Camp Mather
 500 1 0
Usfs Beardsley Picnic Ground
 432 0 0
Yosemite Lakes Campground
 413 1 0
Berkeley Tuolumne Camp
 380 1 0
Usfs Baker/deadman Cgd
 366 1 0
Usfs Sourgrass Campgd
 300 0 0
Yosemite Nps-White Wolf
 300 0 0
Don Pedro Rec Ag:blue Oaks
 296 1 0
Christian Berets Conf. Center
 268 0 0
Foothill Horizons
 230 0 0
San Jose Family Camp
 230 0 0
Usfs Fraser Flat Campgd
 228 1 0
Old Oak Ranch
 217 1 0
Atlas Business Park
 206 1 0
California Odd Fellow-Rebekah
 201 1 0
Camp Jack Hazard
 190 0 0
Marble Quarry Resort
 176 1 0
Sierra Waldorf School
 175 0 0
Usfs Eureka Valley Campgd
 168 1 0
Usfs Black Oak Campground
 160 0 0
Yosemite Nps-Glen Aulin
 150 0 0
Sierra Pacific Industries
 144 1 0
Lake Tulloch Campgrd & Marina
 138 0 0
Jamestown Arco & O'byrnes Ferry Storage
 113 0 0
Usfs Hull Creek Campgd
 108 1 0
Usfs Utica Union Campground
 108 0 0
Kennedy Meadows Resort
 100 1 0
Usbr-Admin Center
 100 0 0
Usfs Dardanelle Camp Brightmn
 100 1 0
Usfs Beardsley Campground
 96 0 0
Historic Priest Station, LLC
 90 2 0
Leland Creek Improvement Assoc
 79 1 0
Usfs Sweetwater Campground
 78 1 0
Teleli Golf Club
 75 1 0
Bumblebee Tract Imp Assoc
 60 0 0
Gus S Steakhouse
 60 1 0
Peach Growers Tract Improv Assoc
 60 1 0
Sonora East Center
 60 1 0
Usfs Groveland Ranger Stn.
 60 1 0
Usfs Lost Claim
 60 1 0
Usfs Sandbar Flat Campgd
 60 1 0
Leland Meadow Water District
 59 1 0
Thomason Tuolumne Rd. Prop (steve's Plac
 57 2 0
Usfs Cherry Valley Campgd
 51 1 0
Cow Creek Permittees Association
 50 1 0
Lake Don Pedro Homeowners
 50 1 0
Dardanelles Resort
 42 0 0
Apple Valley Farms
Sonora 		40 1 0
Rush Creek Lodge Water System
 40 1 0
Sierra Outdoor School
 39 1 0
Yosemite Riverside Inn
 39 2 0
Camp Tuolumne Trails
 36 0 0
Chinese Camp School
 34 1 0
Evergreen Lodge
 30 2 0
Spicer Meadow Campground
 30 1 0
Dodge Ridge Ski Resort
 28 1 0
Houseboat Mini Mart
 27 1 0
Firefall Ranch Water System
 26 2 1
LA Casa Loma River Store
 26 1 0
Long Barn Lodge Inc.
 26 1 0
Nature Whole Food Depot
Sonora 		26 0 0
Pinecrest Elementary School
 26 3 1
Under Canvas-Yosemite
 26 0 0
Inactive systems (156, no longer operating or reporting)

Kept for the record and excluded from the county totals above. Browse inactive systems.

About this data

Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.