PlainEnviro

Mason, WA

Low Risk (16/100)

A PlainEnviro-computed score from reported facility/violation counts, not an official EPA rating, health forecast, or population-adjusted rate. See methodology.

Environmental data for Mason in Washington · Population: 66,968

Mason, WA is tracked across three EPA datasets covering 1 Toxics Release Inventory (TRI) facility, 106 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 16/100 (Low Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.

Industrial disclosures inside the county total 1 lbs of reported toxic releases under EPCRA Section 313, while 7 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 21 and a peak AQI of 73 in 2024, with 93% of observed days rated "Good" (0–50).

All figures below draw directly from federal EPA records, TRI self-reported emissions, SDWIS compliance history, NPL Hazard Ranking System scores, and AQS daily AQI summaries, and are not adjusted, weighted, or forecast. A past violation or elevated score does not itself indicate current unsafe conditions; it documents the regulatory and disclosure history publicly filed with the U.S. Environmental Protection Agency through the most recent reporting cycle.

Population
66,968
TRI Facilities
1
Water Systems
106
Superfund Sites
0
Total Releases
1 lbs

Air Quality History (2020–2024)

EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.

Year Good Moderate Unhealthy (SG) Max AQI
2024 341 (93%) 25 0 73
2023 313 (86%) 49 1 106
2022 302 (83%) 60 3 125
2021 339 (94%) 22 0 70
2020 312 (87%) 36 2 397
2024 Good Air Quality: 93% of days
Median AQI: 21

Source: EPA Air Quality System (AQS) Annual AQI by County EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)

For real-time air quality readings and pollutant breakdowns in Washington, see the EPA's AirNow.gov.

Water Systems (106)

System Population Violations
SHELTON CITY OF 17,575 0
BELFAIR WATER DISTRICT 1 4,432 0
LAKE CUSHMAN SYSTEM 5 3,675 0
TIMBERLAKE COMMUNITY CLUB INC 2,337 0
WASHINGTON CORRECTIONS CENTER 2,223 0
ALDERBROOK WATER CO 2,154 0
LAKE LIMERICK WATER 2,148 0
LAKELAND VILLAGE WATER 2,120 0
SUNNYSLOPE 2,112 0
HOODSPORT 1,853 0
SQUAXIN CONSOLIDATED 1,500 4
Shorecrest Estates Water Co 1,321 0
SKOKOMISH 1,150 0
BEARDS COVE 1,100 0
FAWN LAKE MAINTENANCE COMM 1,044 0
CAPE GEORGE COLONY CLUB INC 1,022 0
LAKE CUSHMAN SYSTEM 3 917 0
UNION 700 0
OAK PARK 695 0
TWANOH FALLS BEACH CLUB 481 0
HARTSTENE POINTE 460 4
PORT OF ALLYN 397 0
DELPHI 381 0
HOOD CANAL 368 0
Tahuya River Valley Water District 367 0
LAKE LUCINDA COMMUNITY CLUB 360 0
LAKE ARROWHEAD 343 0
EMERALD LAKE 331 0
RUSTLEWOOD 322 0
MAGGIE LAKE WATER DISTRICT 287 0
COLONY SURF WATER SUPPLY 285 0
VIEW RIDGE HEIGHTS 271 0
ISLAND LAKE MANOR 233 0
COUGAR RIDGE 216 0
RIVERHILL HOMEOWNERS ASSN 215 0
TRAILS END WATER DISTRICT 211 0
WOODLAND MANOR 192 0
VUECREST 191 0
HIGHLAND PARK 180 0
TRITON HEAD ASSN 176 0
LAKEWOOD HEIGHTS 170 3
PIRATES COVE COUNTRY CLUB 168 0
RAINBOW LAKE 168 0
CANAL MUTUAL WATER 167 0
LAUREL PARK COMMUNITY LLC 165 0
BELLWOOD A 163 0
BEACON POINT COMMUNITY CLUB 158 0
SHADOWOOD 154 2
Mission Creek Tracts 150 0
HIDDEN HAVEN MOBILE HOME PARK 149 0
DAYTON TRAILS 148 0
WILDAIRE ESTATES 146 13
EVERGREEN MOBILE HOMEOWNERS CO-OP 140 0
BAYSHORE 130 0
HOLIDAY BEACH WATER SUPPLY 130 0
AYOCK BEACH IMPROVEMENT 129 0
ENCHANTED FIRS MOBILE ESTATES 120 0
TWANOH HEIGHTS COMMUNITY CLUB 118 0
CHERRY PARK 111 0
ARCADIA ESTATES 110 0
HIGHLAND ESTATES 110 0
POTLATCH BEACH MUTUAL 109 0
SHORE HILL 101 0
BAY EAST 96 0
PENINSULA MOBILE PARK 92 0
SPRINGWOOD 90 0
HARSTENE RETREAT 88 0
COOPER POINT WATER CO 85 0
MINERVA TERRACE 85 0
WONDERLAND WATER COMPANY 82 0
LAKE LAWRENCE MOBILE HOME PARK 80 0
EDGEWATER BEACH WATER CO 78 0
WESTERN AIRPARK 78 0
TWANOH TERRACE WATER CO 75 0
MADRONA PARK 73 0
RAE LAKE 73 0
RHODODENDRON PLACE 70 0
TIGER LAKE TERRACE TRACTS 70 0
WOODLAND PARK UTILITY ASSN 68 0
HOLIDAY ACRES 65 0
Sylvan Terrace Condominiums 64 0
ORCHARD BEACH COMMUNITY 64 0
PEBBLE BEACH 64 0
HAMMA RIDGE 63 0
PARKWOOD APARTMENTS 60 3
NEW PINE ACRES 60 0
CEDAR PARK 53 1
BOLDUC COMMUNITY 51 0
AGATE BEACH 48 0
LITTLE MISSION CREEK 47 0
Ripplewood Tracts 45 0
Allyn Carey 45 0
CANYONWOOD BEACH WATER SUPPLY 43 0
LAKEWOOD MANOR ASSOCIATION 42 0
MOUNTAIN VIEW 41 0
OLYMPIC VISTA CLUB COMMUNITY WATER 41 0
PRINE DRIVE APARTMENTS 40 0
MOUNTAIN SHORES 40 0
VIEWCREST BEACH 40 0
KAMILCHE POINT COMMUNITY CLUB 39 0
RAINIER VIEW 37 0
SHERMAN HILL 37 0
BEL AIRE COVE 32 0
VALLEY VIEW MOBILE HOME PARK 30 0
ELMA EVERGREEN VILLAGE 29 0
Queen Anne Water Works LLC 28 0

TRI Facilities (1)

# Facility Total Releases
1 Sierra Pacific Industries - Shelton 1 lbs

Cities in Mason (1)

Shelton
Pop: -
1 facilities · 58 water

Frequently Asked Questions

What is the environmental risk level in Mason, Washington? ▼
Mason, WA has an environmental risk score of 16/100 (Low Risk), based on 1 TRI facilities, 0 Superfund sites, and 106 water systems on record. 7 water systems have health-based violations. Source: EPA TRI, SDWIS, and Superfund NPL.
Are there Superfund sites in Mason? ▼
No Superfund National Priorities List (NPL) sites are currently registered in Mason, WA in the EPA database.
How many toxic release facilities are in Mason? ▼
Mason, WA has 1 TRI-reporting facility on record with the EPA Toxic Release Inventory, with a combined total of 1 lbs in reported toxic releases. TRI facilities self-report annual chemical release data to the EPA.
What is the air quality in Mason? ▼
In 2024, Mason, WA recorded a median AQI of 21 and a peak AQI of 73. 93% of monitored days had "Good" air quality (AQI 0–50). Source: EPA Air Quality System (AQS) Annual AQI by County.
Is the drinking water safe in Mason? ▼
Mason, WA has 106 EPA-regulated water systems. 7 systems have reported health-based violations (MCL exceedances). A past violation does not necessarily mean water is currently unsafe. For current water quality, contact your local water utility. Source: EPA SDWIS.
What environmental agencies cover Mason? ▼
Environmental compliance in Mason, Washington is overseen by the U.S. Environmental Protection Agency (EPA) at the federal level and the Washington state environmental agency. Facilities report to the EPA Toxic Release Inventory, water systems are regulated under the Safe Drinking Water Act, and contaminated sites are managed under the Superfund program. Contact your state environmental agency for local concerns.

What does this county environmental profile show?

This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.

Related Guides

Understanding EPA Data
How EPA collects and publishes environmental data
Environmental Justice
Who lives near polluters and environmental hazards
How to Check Environmental Quality
Step-by-step guide to checking your local environment

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from U.S. EPA environmental datasets. See our methodology for details. Retrieved and formatted by PlainEnviro Editorial