Updated Aug 2026
Washington Lake Water Quality
792 lakes across 35 counties, 45 with a recent water-quality reading.
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New water-quality readings for Washington lakes as Washington Ecology publishes them. Unsubscribe anytime.
Where to stay near Washington's cleanest lakes
Cabins, resorts, and vacation rentals around Fdr Lake and the other cleanest Washington lakes pinned on the map. Live availability and prices.
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Explore Washington Lakes
Washington reports, fishing & travel
Reservoirs in Washington
View all 9 reservoirs →9 of 792 Washington lakes (1%) are man-made reservoirs in the USACE National Inventory of Dams. 6 carry a High or Significant hazard rating. The oldest matched dam dates to 1911.
EPA-Impaired Lakes in Washington
View all 153 impaired lakes →153 of 792 Washington lakes (19%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 12 have an approved Total Maximum Daily Load (TMDL) restoration plan.
Washington Fishing & Recreation
Licenses, regulations, records, and where to fish across Washington.
Counties
All 35 Washington counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of lakes, or pick a different state.
45 of the 792 Washington lakes in this index carry a recent clarity, phosphorus or algae reading, spread over 35 counties. Those readings come from the Washington State Department of Ecology, alongside federal programs and volunteer monitoring networks. The rest are listed for their size, depth and location, with no recent nutrient or algae sampling behind them.
By surface area the largest lake here is Banks Lake, at about 27,000 acres, and 75 of the lakes in this index cover more than 500 acres. Size is worth knowing before you go: a large deep basin buffers nutrient inputs by sheer volume, while a shallow one warms quickly and can turn over its whole water column in a single summer storm. Lincoln has the lowest nutrient and algae readings on average. With only 35 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of lakes that fit, with the water quality behind each one.
Source: EPA National Aquatic Resource Surveys and the EPA Water Quality Portal.
More on lake water quality
A data snapshot of the lakes we track: the clearest and the greenest states, and where the water is improving.
How nutrient and algae readings are read against EPA ecoregion condition classes, what each class means in the water, and why a clean reading is not a clearance.
The clearest lakes in America, ranked by measured Secchi depth in feet from EPA monitoring data — and why the famously clear lakes are missing.