Thurston County Lake Quality
Washington, 19 lakes, average grade B (Good)
There are 19 graded lakes in Thurston County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake: Ward Lake (A) is the cleanest in the county.
Quick Answers for Thurston County
Planning a trip? Check special fishing regulations for Lake: Ward Lake — or check the official Washington fishing regulations.
All Lakes in Thurston County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Lake: Ward Lake | A | - | 10.5 µg/L |
| 2 | Lake: Summit Lake | A | - | 6 µg/L |
| 3 | Lake: Deep Lake | A | - | 7 µg/L |
| 4 | Lake: Hicks Lake | A | - | 16 µg/L |
| 5 | Lake: Pattison Lake | B | - | 26.5 µg/L |
| 6 | Lake: Barnes Lake | B | - | 27 µg/L |
| 7 | Lake: Offutt Lake | B | - | 23 µg/L |
| 8 | Nla Lake | D | 7.7 ft | 26517.8 µg/L |
| 9 | Nla Lake | D | 4.9 ft | 46029.7 µg/L |
| 10 | Lake | F | - | 126.5 µg/L |
Other Counties in Washington
See how Thurston County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
Where to stay near Thurston County
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Source: EPA National Aquatic Resource Surveys, 2026.