Tapcensus

Washington

Mason County drinking water quality

242 active public water systems serve 76,405 people in Mason County. 154 are compliant, 88 had at least one EPA violation in the past three years, 2 are designated serious violators, and 0 carry a health flag.

Active systems 242 120 community systems
People served 76K by public water systems
Systems with violations 88 36% of active systems, past 3 years
Serious violators 2 0 systems carry a health flag

Needs attention

Trails End Water District WA5389055 · Community water system · Serves 211 6 rules violated in the past three years
Potlatch Beach Mutual WA5369050 · Community water system · Serves 109 3 rules violated in the past three years

Community water systems

120 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Mission Creek Tracts
 150 0 0
Hidden Haven Mobile Home Park
 149 1 0
Dayton Trails
 148 0 0
Shorebrook Community Club
 148 1 0
Evergreen Mobile Homeowners Co-Op
 140 0 0
Bayshore
 130 1 0
Holiday Beach Water Supply
 130 0 0
Ayock Beach Improvement
 129 0 0
Three Fingers
 118 0 0
Twanoh Heights Community Club
 118 0 0
River Haven
 113 2 1
Cherry Park
 111 0 0
Arcadia Estates
 110 0 0
Highland Estates
 110 0 0
Potlatch Beach Mutual
 109 3 0
Lynch Cove Div 1 Water Assn
 102 0 0
Shore Hill
 101 3 0
Bar B Estate Manor
 96 0 0
Bay East
 96 0 0
Mason County Lost Lake
 96 0 0
Cedar View Tracts Comm Club
 90 0 0
Springwood
 90 0 0
Harstene Retreat
 88 0 0
Minerva Terrace
 85 0 0
Wonderland Water Company
 82 1 0
Minerva Beach Resort
 80 0 0
Twanoh Terrace Water CO
 75 0 0
Madrona Park
 73 1 0
Rae Lake
 73 1 0
Rhododendron Place
 70 0 0
Tiger Lake Terrace Tracts
 70 0 0
Clifton Beach Tracts CO OP
 65 1 0
Jesfield Tracts Community Club
 65 1 0
Orchard Beach Community
 64 1 0
Pebble Beach
 64 1 0
Hamma Ridge
 63 1 0
Curries Landing
 61 0 0
New Pine Acres
 60 0 0
Peninsula Pines Park
 60 0 0
Cherokee Strip HOA & Water
 59 1 0
Detroit Water Service Assn
 57 0 0
Harstine Island Estates Assn
 56 1 0
Pleasant Cove
 55 1 0
Spencer Glen
 55 2 0
Lake Christine Community Club
 53 1 0
Clifton Pebble Beach
 52 1 0
Bolduc Community
 51 1 0
Tahja II
 51 2 0
Agate Beach
 48 0 0
Little Mission Creek
 47 2 0
Non-community systems (122: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Twanoh State Park
 3,173 0 0
Belfair State Park
 2,411 0 0
North Mason High School
 1,300 1 0
Potlatch State Park
 1,055 1 0
Pioneer School District
 903 1 0
Jarrell Cove State Park
 715 0 0
Sand Hill Elementary
 650 1 1
Schafer State Park
 465 0 0
Ridge Motorsports Park
 403 0 0
Port of Shelton Johns Prairie
 328 0 0
Panhandle Lake 4h Camp
 315 0 0
Taylor Station
 314 0 0
Port of Shelton Sanderson Field
 283 0 0
Mary M Knight School
 270 0 0
Southside Elementary School
 260 0 0
Grapeview School
 257 1 0
Union Food Mart
 255 0 0
Shelton Valley Child Development
 221 0 0
Green Diamond Park
 200 0 0
Taylor United
 187 0 0
Skyline Drive in Theater
 169 0 0
Camp Lyle McLeod
 153 0 0
Sandhill Park
 152 0 0
Spencer Lake Bar and Grill
 150 1 0
Camp Robbinswold Girl Scout
 142 0 0
Camp ST Albans Girl Scout
 136 0 0
Cushman INC
 129 0 0
Hama Hama Company
 125 0 0
Prairie
 122 0 0
Deer Creek Grocery
 111 2 0
Lake Trask Timber Trails Assn
 107 2 0
Airport Grocery
 105 2 0
Canal Beach Tracts Mutual Wtr CO
 102 0 0
Kimberley T
 100 0 0
Zions Camp Lds Recreational Prop
 97 1 0
Staircase Campground
 91 0 0
Alta Forest Products
 90 0 0
Camp Bishop Grays Harbor YMCA
 83 0 0
Christ Lutheran Church
 83 0 0
Eagle Creek Tavern
 83 0 0
Pats Little Red Barn INC
 83 0 0
Dry Sort Domestic
 80 0 0
Mason County Public Works
 80 0 0
North Mason Bible Church
 78 0 0
Discovery Homes #1
 76 0 0
Prince of Peace Catholic Church
 71 2 0
Stretch Island Fruit
 70 0 0
Hilburn Scott
 68 0 0
Lake Nahwatzel Resort
 68 0 0
Blue Heron Condominiums
 67 0 0
Olympic Mountain Ice Cream
 66 1 0
Brown Creek Campground HP B
 65 1 0
Brown Creek Campground HP C
 65 1 0
Jarrells Cove Marina
 64 1 0
Spencer Lake RV Park
 64 0 0
New Community Church of Union
 63 1 0
Fresh Start
 60 0 0
Vig
 60 0 0
Harstine Island Community Club
 59 1 0
Hill Valley
 57 1 0
Shelton Presbyterian
 57 0 0
Agate Grocery
 56 1 0
Big Creek Campground Olympic NF
 54 1 0
Golden Pheasant Tavern
 54 0 0
Allyn Shop
 52 1 0
Madrona Beach Supply
 50 0 0
Teamsters 313 Rec Area
 49 1 0
Webb Hill
 48 0 0
Shelton Auto Parts
 47 0 0
Olympia Oyster CO
 46 0 0
Lds Church (belfair Building)
 43 1 0
Harmony Hill
 41 0 0
Mission Creek Corrections Center
 40 1 0
Purdy Canyon Restaurant
 38 0 0
Bpo Elks Lodge #2467
 34 0 0
Jorstad Creek Resort
 34 0 0
Pickering Spencer Lake
 34 0 0
Lilliwaup Store and Motel
 33 1 0
McSaa
 33 0 0
Seventh Day Adventist School
 33 0 0
Bear Creek Store
 32 2 0
Hood Canal Cooperative 1
 32 0 0
Merrimount 1
 32 0 0
Clear Water Maintenance
 31 0 0
Elma Country Club
 31 0 0
Canal View
 30 0 0
Cornerstone Industrial Park
 30 1 0
Jafbro Associates
 30 0 0
Jafbro 2
 30 2 0
Matlock General Store
 30 0 0
Rest a While RV Park
 30 2 0
Happy Hollow Grocery
 29 2 0
Sunrise Motel
 29 1 0
Purdy Creek
 28 0 0
S&p Properties
 27 1 0
Wagon Wheel Estates
 27 0 0
Island Hide a Way Water
 26 1 0
Ten Four
 26 1 0
Alta Drive
 25 0 0
Brisco Point
 25 0 0
All 122 in the systems table
Inactive systems (195, 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 Washington 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.