Franklin County Lake Quality
Ohio, 1 lakes, average grade F (Very Poor)
Only 1 lakes in Franklin 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 average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
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. Hoover Reservoir (F) is the cleanest in the county.
Quick Answers for Franklin County
Planning a trip? Check special fishing regulations for Hoover Reservoir — or check the official Ohio fishing regulations.
All Lakes in Franklin County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Hoover Reservoir | F | - | 64.1 µg/L |
Other Counties in Ohio
See how Franklin County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 36 states and 2 Canadian provinces.
Where to stay near Franklin County
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Source: EPA National Aquatic Resource Surveys, 2026.