Lakes With Algae Problems in Ohio
28 lakes in Ohio report elevated algae levels (chlorophyll-a above 20 µg/L). These lakes are most likely to develop blue-green algae blooms during warm, calm summer weather. Avoid swimming during visible blooms and rinse pets after contact.
Ranked List
| # | Lake | County | Grade | Clarity | Phosphorus | Algae |
|---|---|---|---|---|---|---|
| 1 | Grand Lake St Marys | Mercer | F | - | 350 µg/L | 120.5 µg/L |
| 2 | Grand Lake St Marys @ Intake | Mercer | F | - | 395.5 µg/L | 116.5 µg/L |
| 3 | Spring Valley Lake Lake | Columbiana | F | - | 396.5 µg/L | 84.3 µg/L |
| 4 | Auglaize R Lake | Paulding | F | - | 130.5 µg/L | 72.6 µg/L |
| 5 | Tappan Lake @ Cadiz Public Water Supply Intake | Harrison | NR | - | 66.1 µg/L | 72.1 µg/L |
| 6 | Hoover Reservoir | Delaware | F | - | 168 µg/L | 69.8 µg/L |
| 7 | Tapan Lake Adj To Marina | Harrison | NR | - | 47.1 µg/L | 65.3 µg/L |
| 8 | Somerset Reservoir | Perry | F | - | 41.7 µg/L | 63.5 µg/L |
| 9 | St Joseph Lake | Perry | F | - | 58.9 µg/L | 58.7 µg/L |
| 10 | Alum Creek Lake | Delaware | F | - | 80.6 µg/L | 53.9 µg/L |
| 11 | Tappan Lake | Harrison | F | 1.8 ft | 70 µg/L | 53.8 µg/L |
| 12 | Maumee R Upst Independence Dam Lake | Defiance | D | - | 197.5 µg/L | 51.3 µg/L |
| 13 | O'Shaughnessy Reservoir Lake | Delaware | F | - | 157 µg/L | 49.3 µg/L |
| 14 | Hoover Reservoir | Franklin | F | - | 64.1 µg/L | 43.2 µg/L |
| 15 | Buck Creek Lake | Clark | F | 2.5 ft | 44 µg/L | 42.1 µg/L |
| 16 | Buck Creek Lake | Clark | F | 2.3 ft | 43.5 µg/L | 39.7 µg/L |
| 17 | Bresler Reservoir | Allen | F | - | 78.1 µg/L | 39.4 µg/L |
| 18 | Amicks Reservoir | Morrow | F | - | 60.9 µg/L | 38.1 µg/L |
| 19 | Buck Creek Lake | Clark | F | 2.5 ft | 41.5 µg/L | 36.8 µg/L |
| 20 | Buck Creek Lake | Clark | F | 2 ft | 51 µg/L | 33.7 µg/L |
| 21 | Sandusky Bay Spatial Composite Lake | Ottawa | NR | - | - | 31 µg/L |
| 22 | Maumee Bay Off Maumee Bay State Park Lake | Lucas | NR | - | 66 µg/L | 30.6 µg/L |
| 23 | Sandusky Bay Ambient Station Off Johnson'S Island Lake | Erie | NR | - | 68.2 µg/L | 30.5 µg/L |
| 24 | Upper Sandusky Reservoir | Wyandot | D | - | 56.5 µg/L | 29.4 µg/L |
| 25 | Maumee Bay Off Woodtick Peninsula Lake | Lucas | NR | - | 76.1 µg/L | 28 µg/L |
| 26 | Lake Logan | Hocking | D | - | 45.8 µg/L | 25.6 µg/L |
| 27 | Burr Oak Reservoir | Morgan | D | - | 35.1 µg/L | 24 µg/L |
| 28 | Tappan Lake Upper End of Lake | Harrison | NR | - | 68.3 µg/L | 22.4 µg/L |