Mason Lake
Mason County, Washington977 acresView mapDirections
No nutrient or algae sampling on record from Washington Ecology for this lake.
- Impaired · Mercury
- 90 ft max depth
Mason Lake in Mason County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Maximum depth: 90 ft. Surface area: 977 acres.
Mason Lake is a 977-acre lake in Mason County, Washington with a maximum depth of 90 feet.
Source: EPA Water Quality Portal sampling records, WA Ecology. Methodology: how these readings are compared.
What Mason Lake is good for
From access and monitoring records, not editorial picks.
- Camping1 public campground nearby
- Deep water90 ft surveyed max depth
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Mason Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nuisance exotic species. Check local advisories before you swim.
Whether Mason Lake is safe to swim in today is a call for the Washington State Department of Ecology and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mason Lake
These are the measurements Washington Ecology publishes for Mason Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Mason Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
90 ft
Surface area
977 acres
Shoreline
11.1 mi
Recreation & Access
Public campgrounds near Mason Lake
- Twanoh State Park Campground4.6 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Mason Lake
Compare lakeside cabins, hotels, and vacation rentals near Mason Lake in Mason County, Washington — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Mason Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fishing Mason Lake
EPA Impairment Status
Mason Lake is officially listed as impaired under Clean Water Act §303(d) in the 2018 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
Source: EPA ATTAINS assessment unit WA17110019001157_001_001 · Official waterbody report
Nearby Lakes in Mason County
Frequently asked questions about Mason Lake
Where is Mason Lake?
- Mason Lake is a lake in Mason County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Mason Lake?
- Mason Lake in Mason County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Maximum depth: 90 ft. Surface area: 977 acres.
Is Mason Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mason Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nuisance exotic species. Check local advisories before you swim.
How deep is Mason Lake?
- Mason Lake has a maximum depth of 90 feet. The lake covers 977 acres.
Are there campgrounds on Mason Lake?
- Mason Lake has 1 public campground from USGS The National Map within 5 km, including Twanoh State Park Campground. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
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Where this data comes from
Measurements for Mason Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Public campgrounds from USGS The National Map Structures, within about 3 miles