Where is Lake Washington?

Lake Washington is a lake in King County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.

Are there boat ramps on Lake Washington?

Lake Washington has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Magnuson Park. Public access is listed as yes.

Can I fish at Lake Washington?

Lake Washington has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Washington's fish and wildlife agency, so check its current regulations before you go.

Lake Washington

King County, Washington21,992 acresView map Directions

No nutrient or algae sampling on record from Washington Ecology for this lake.

Area

21,992 acres

Surface area

Shoreline

64.5 mi

Measured length

Impaired · Mercury
Public access

See the measurements Directions Where to stay

Lake Washington in King County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Surface area: 21992 acres.

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Lake Washington is a 21,992-acre lake in King County, Washington. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, WA Ecology. Methodology: how these readings are compared.

What Lake Washington is good for

From access and monitoring records, not editorial picks.

Boat launch1 documented ramp
Big water21,992 acres

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Lake Washington is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pCBs. Check local advisories before you swim.

Whether Lake Washington 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.

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Water quality measurements for Lake Washington

These are the measurements Washington Ecology publishes for Lake Washington, 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 Lake Washington

Answers come straight from the public measurements and survey records on this page.

Lake Details

Surface area

21,992 acres

Shoreline

64.5 mi

Public access

Yes

Listed by Washington Ecology

No bathymetric survey has been published for Lake Washington, so its depth is not documented here.

Recreation & Access

Boat Landings

Yes

Public Access

Magnuson ParkPublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Stays via Stay22

Stays near Lake Washington

Compare lakeside cabins, hotels, and vacation rentals near Lake Washington in King 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 Lake Washington

Prices for Oct 16–18, 4 adults. Change dates on the map below.

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Planning a trip? Cabins and lodging at Lake Washington → · more Washington lake trips

Follow Lake Washington’s readings

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Fishing Lake Washington

→ Lake Washington fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Lake Washington is officially listed as impaired under Clean Water Act §303(d) in the 2018 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryPCBs

Designated uses not supporting: Fish consumption.

Source: EPA ATTAINS assessment unit WA47122G2C5_01_01 · Official waterbody report

Nearby Lakes in King County

Lake Union3.6 miView →Green Lake5 miView →Lake Washington Ship Canal5.9 miView →Phantom Lake6.8 miView →Lake Sammamish11.5 ft clear8.2 miView →Burien Lake—View →

Frequently asked questions about Lake Washington

Where is Lake Washington?: Lake Washington is a lake in King County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Lake Washington?: Lake Washington in King County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Surface area: 21992 acres.
Is Lake Washington safe to swim in?: Nutrient and algae readings are not a swimming clearance. Lake Washington is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pCBs. Check local advisories before you swim.
Are there boat ramps on Lake Washington?: Lake Washington has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Magnuson Park. Public access is listed as yes.
Can I fish at Lake Washington?: Lake Washington has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Washington's fish and wildlife agency, so check its current regulations before you go.