Denton County Lake Quality
Texas, 6 lakes, average grade D (Poor)
Only 6 lakes in Denton 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. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 0 lakes fall into the F bracket outright.
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 Ray Roberts Lake Site (B); the most-stressed is Lewisville Lake Elm Fork (D).
Quick Answers for Denton County
Planning a trip? Check special fishing regulations for Ray Roberts Lake Site — or check the official Texas fishing regulations.
All Lakes in Denton County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Ray Roberts Lake Site | B | 3.9 ft | 20.1 µg/L |
| 2 | Lewisville Lake | C | 1.8 ft | 43 µg/L |
| 3 | Grapevine Lake Northwest | C | 2.4 ft | 40 µg/L |
| 4 | Lewisville Lake Site | C | 2.4 ft | 30 µg/L |
| 5 | Lewisville Lake Elm Fork | D | 2.4 ft | 70 µg/L |
Other Counties in Texas
See how Denton 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 Denton County
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Source: EPA National Aquatic Resource Surveys, 2026.