Rock County, WI
Home Menu2026 Surface Water Sampling
| E. coli cfu per 100 ml | |
| 0-235 | Normal conditions |
| 235-999 | Caution advisory |
| 1000+ | High risk advisory* |
| Harmful Algal Blooms (Blue Green Algae) Observed* | |
*Surface waterways may not be suitable for recreational activities resulting in the ingestion of water.
Note: Licensed Beaches (B) are CLOSED when E. coli counts are 1000+
Weekly Test Sites
| Date Tested | Lakeview Campground - Lake Koshkonong (B) | Lakeland Campground - Lake Koshkonong (B) | Blackhawk Campground - Clear Lake (B) | Traxler Park Rock River | Preservation Park - Rock River |
| 2/23/2026 | N/A | 6 | <1 | N/A | 36 |
| 5/4/2026 | 10 | 31 | 1 | 12 | 20 |
| 5/11/2026 | 29 | 6 | <1 | 6 | 10 |
| 5/18/2026 | 5 | 186 | <1 | 44 | 31 |
| 5/26/2026 | 12 | 10 | 4 | 23 | 32 |
| 6/1/2026 | 12 | 13 | 4 | 18 | 35 |
| 6/9/2026 | 42 | 225 | 12 | 79 | 64 |
| 6/16/2026 | 62 | 81 | 6 | 46 | 53 |
| 6/22/2026 | 9 | 196 | 14 | 138 | 124 |
| 6/29/2026 | 13 | 84 | 6 | 35 | N/A |
| 7/1/2026 | N/A | N/A | N/A | N/A | 62.4 |
| 7/6/2026 | 9 | 57 | 20 | 73 | 113 |
| 7/13/2026 | 15 | 20 | 4 | 30 | 35 |
| 7/20/2026 | 28 | 44 | 7 | 60 | 67 |
| 7/27/2026 | 17 | 27 | <1 | 82 | 43 |
| 8/3/2026 | 35 | 30 | 2 | 921 | 1046 |
| 8/10/2026 | 17 | 93 | 201 | 60 | 166 |
| 8/17/2026 | 37 | 108 | 5 | 72 | 206 |
| 8/24/2026 | 19 | 33 | 3 | 45 | 185 |
| 8/31/2026 | 70 | 66 | 4 | 39 | 166 |
| 9/8/2026 | 27 | 115 | 5 | 48 | 63 |
Monthly Test Sites
| Date Tested | Gibbs Lake | Sugar River | Storrs Lake |
Palmer Park - Spring Brook |
Carver - Roehl Spring Brook | Yahara River - Murwin Park | Badfish Creek | Turtle Creek |
| 2/23/2026 | N/A | 26 | N/A | <1 | 57 | 173 | 1046 | 11 |
| 5/4/2026 | N/A | N/A | N/A | N/A | N/A | 49 | N/A | N/A |
| 5/27/2026 | 88 | 86 | 1 | 29 | 133 | 345 | 548 | 219 |
| 6/22/2026 | 50 | 579 | 5 | >2419.6 | 687 | 145 | 517 | 579 |
| 7/21/2026 | 10 | 196 | 15 | 1300 | 687 | 138 | 461 | 249 |
| 8/25/2026 | 12 | 102 | 2 | 1300 | 435 | 201 | 548 | 131 |
Seasonal Sites
| Date Tested | Kiwanis Pond | Otter Creek | Lake Leota | Saunders Creek | Traxler Park Lagoon | Leeson Park |
| 2/23/2026 | N/A | N/A | N/A | N/A | N/A | N/A |
| 6/22/2026 | 6 | 387 | 62 | 291 | 34 | 1414 |
| Date Tested | Stebbinsville - Yahara River | Marsh Creek | Bass Creek | Fisher Creek | Beckman Mill Pond | Beloit Lagoon |
| 2/23/2026 | 148 | N/A | N/A | N/A | N/A | N/A |
| 6/22/2026 | 79 | >2419.6 | >2419.6 | 770 | 1120 | 58 |
