Grand Forks County Lake Quality
North Dakota, 4 lakes, average grade C (Fair)
Grand Forks County has 4 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 2 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. Grand Forks County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
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 Larimore Dam Lake (C); the most-stressed is Larimore Dam Lake (C).
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Quick Answers for Grand Forks County
Planning a trip? Check special fishing regulations for Larimore Dam Lake — or check the official North Dakota fishing regulations.
All Lakes in Grand Forks County
4 lakes · 2 graded, 2 not rated2 graded lakes · 2 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | CLarimore Dam LakeGrand Forks | C | 3 ft | 225 µg/L | 13.3 µg/L | No recent samples | ✓ Public |
| 2 | CFordville Dam LakeGrand Forks | C | 4.4 ft | 411 µg/L | 5.2 µg/L | No recent samples | ✓ Public |
| NRKolding Dam LakeGrand Forks | NR | 1.7 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRNiagara Dam LakeGrand Forks | NR | 1 ft | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Other Counties in North Dakota
See how Grand Forks County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 49 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.