Lake Washington
Lake Washington in King County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 21992 acres.
- Area
- 21,992 acres
- Public access
- Yes
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Why Lake Washington has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Washington, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WA Ecology and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Lake Washington
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay 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
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 21,992 acres |
| Public Access | Yes |
No bathymetric survey has been published for Lake Washington, so its depth is not documented here.
Recreation & Access
- Magnuson ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lake Washington
Nearby Lakes in King County
Frequently asked questions about Lake Washington
Where is Lake Washington?
- Lake Washington is a lake in King County, Washington. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Lake Washington?
- Lake Washington in King County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 21992 acres.
Is Lake Washington safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Lake Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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.
Explore Lake Washington across LakeQuality
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Where this data comes from
Measurements for Lake Washington come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory