Washington County Lake Quality
Texas, 2 lakes, average grade F (Very Poor)
Washington County has 2 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
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 Somerville Lake (D); the most-stressed is Somerville Lake Upper Portion (F).
Quick Answers for Washington County
Planning a trip? Check special fishing regulations for Somerville Lake — or check the official Texas fishing regulations.
All Lakes in Washington County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Somerville Lake | D | 1.9 ft | 90 µg/L |
| 2 | Somerville Lake Upper Portion | F | 0.9 ft | 155 µg/L |
Other Counties in Texas
See how Washington County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 17 states.
Where to stay near Washington County
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Source: EPA National Aquatic Resource Surveys, 2026.