Somerville Lake Upper Portion is a highly nutrient-loaded hypereutrophic lake in Washington County, Texas. Water quality is graded F based on 2 sampling years through 2025. Compared to the 1 other monitored lakes in Washington County, Somerville Lake Upper Portion ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Texas DNR, last sampled 2025-11-18. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 0.9 ft of visibility. Phosphorus level: 155 µg/L. Chlorophyll-a: 97.1 µg/L. Trophic State Index: 77.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | F |
| Phosphorus | 155 µg/L | F |
| Chlorophyll-a (Algae) | 97.1 µg/L | F |
| Trophic State Index (TSI) | 77 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Somerville Lake Upper Portion
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Fishing Somerville Lake Upper Portion
Location
County Ranking
Ranked #2 of 2 lakes in Washington County
Cleaner Lakes Within 30 Miles
Somerville Lake Upper Portion holds Grade F. 2 nearby lakes hold higher grades.
- DSomerville Lake Big Creek ArmBurleson County · 5.6 mi · Higher grade (F → D)
- DSomerville LakeWashington County · 7.1 mi · Higher grade (F → D)
Nearby Lakes in Washington County
Explore Somerville Lake Upper Portion across LakeGrade
More Texas Lake Rankings
Other Grade F Lakes in Texas
Burleson County · Clarity: 1.8 ft
Falls County · Clarity: 1.5 ft
Limestone County · Clarity: 1 ft
Limestone County · Clarity: 1.1 ft
Harris County · Clarity: 1.5 ft
Polk County · Clarity: 1.6 ft
Hypereutrophic Lakes in Texas
More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-11-18
Monitoring stations: 1