Washington County Lake Quality
Oregon, 2 lakes, average grade A (Excellent)
Only 2 lakes in Washington County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. On average, Washington County lakes grade an A. That puts it near the top of the {{stateName}} county ranking.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Henry Hagg Lake (A); the most-stressed is Henry Hagg Lake (A).
Quick Answers for Washington County
Planning a trip? Check special fishing regulations for Henry Hagg Lake — or check the official Oregon fishing regulations.
All Lakes in Washington County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Henry Hagg Lake | A | - | - |
Other Counties in Oregon
See how Washington County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 27 states.
Where to stay near Washington County
Top-rated places to stay near Washington County
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Washington County?
Get lake water-quality report cards plus the best cabin & lodging deals near Washington County — straight to your inbox. No spam, unsubscribe anytime.
Source: EPA National Aquatic Resource Surveys, 2026.