Grant County Lake Quality
Wisconsin, 3 lakes, average grade D (Nutrient-rich)
Only 3 lakes in Grant 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. On average, Grant County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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. Jones Slough Lake (C) is the cleanest in the county.
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Quick Answers for Grant County
Planning a trip? Check special fishing regulations for Jones Slough Lake — or browse the full Wisconsin regulations index.
All Lakes in Grant County
3 lakes3 graded lakes
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|---|
| 1 | CJones Slough LakeGrant | C | 4.9 ft | 31 µg/L | No recent samples | No recent samples | No recent samples | ✓ Public |
| 2 | DRice LakeGrant | D | 4.6 ft | 66.6 µg/L | No recent samples | No recent samples | 5 ft | ✓ Public |
| 3 | DUnknown LakeGrant | D | 2.4 ft | 135.5 µg/L | No recent samples | No recent samples | No recent samples | Not recorded |
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Other Counties in Wisconsin
See how Grant County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.