| Percent Samples with Five Day Biochemical Oxygen Demand (BOD5) more than 5 mg/L | |||||||
| Watershed | Mar-Apr | May-Jun | Jul-Aug | Sep-Oct | Winter | All Seasons | |
| Bois De Sioux | 38 | 24 | 54 | 31 | 2 | 28 | |
| Mustinka | 0 | 40 | 0 | 25 | 43 | 31 | |
| Otter Tail | 3 | 5 | 7 | 5 | 2 | 4 | |
| Upper Red | 29 | 20 | 17 | 16 | 19 | 20 | |
| Western Wild Rice | 25 | 50 | na | 50 | 0 | 36 | |
| Buffalo | 9 | 0 | 21 | 17 | 10 | 12 | |
| Elm-Marsh | 30 | 22 | 10 | 13 | 17 | 18 | |
| Eastern Wild Rice | 38 | 19 | 19 | 25 | 22 | 24 | |
| Goose | 29 | 18 | 11 | 20 | 8 | 16 | |
| Devils Lake | 100 | na | na | na | na | 100 | |
| Upper Sheyenne | na | na | na | na | na | na | |
| Middle Sheyenne | 12 | 9 | 7 | 0 | 12 | 9 | |
| Lower Sheyenne | 30 | 15 | 23 | 28 | 15 | 21 | |
| Maple | na | na | na | 100 | 0 | 50 | |
| Sandhill-Wilson | 22 | 8 | 7 | 10 | 9 | 11 | |
| Red Lakes | 0 | 0 | 5 | 20 | 67 | 8 | |
| Red Lake | 17 | 4 | 5 | 5 | 8 | 8 | |
| Thief | na | na | na | na | na | na | |
| Clearwater | 0 | 0 | 6 | 0 | 0 | 3 | |
| Grand Marais - Red | 39 | 6 | 6 | 0 | 18 | 15 | |
| Turtle | na | na | na | na | na | na | |
| Forest | 50 | 50 | 50 | ||||
| Snake | 47 | 19 | 24 | 36 | 29 | 30 | |
| Park | na | na | 100 | 100 | 50 | 80 | |
| Lower Red | 15 | 0 | 6 | 5 | 9 | 7 | |
| Two Rivers | 14 | 6 | 13 | 38 | 24 | 19 | |
| Pembina | 10 | 2 | 3 | 3 | 8 | 6 | |
| Reseau | 24 | 5 | 5 | 11 | 16 | 13 | |