2023 Orono Beach Testing
Lake Orono is tested for E. coli bacteria (Escherichia coli) twice per week from Memorial Day through Labor Day at the public beach. This measure determines fecal contamination in the lake. Elevated bacteria levels can be harmful to humans and can occur after significant rain events when bacteria sources are washed into the lake from land.
Note: We are the only Sherburne County lake that tests for bacteria. All counts are in MPN/100mL.
Counts below 235 MPN/100 mL are considered safe.
Date | North of Beach | Middle of Beach | South of Beach | Geometric Mean of Monthly Counts |
|---|---|---|---|---|
| 8/31/23 | 14.6 | 1986.3 | 5.2 | 53.23 |
| 8/29/23 | 13.2 | 8.6 | 10.9 | |
| 8/24/23 | 58.3 | 14.8 | 5.2 | 16.49 |
| 8/17/23 | 90.6 | 63.1 | 44.8 | |
| 8/15/23 | 68.9 | 49.6 | 69.7 | |
| 8/10/23 | 79.4 | 8.6 | 79.8 | 37.91 |
| 8/8/23 | 127.4 | 20.1 | 95.9 | |
| 8/3/23 | 24.1 | 79.8 | 121.0 | |
| 8/1/23 | 15.5 | 2419.6 | 37.3 | |
| 7/27/23 | 111.2 | 48.8 | 31.8 | |
| 7/25/23 | 10.7 | 4.1 | 7.4 | |
| 7/20/23 | 12.0 | 13.5 | 22.8 | |
| 7/18/23 | 116.2 | 4.1 | 7.3 | |
| 7/13/23 | 125.9 | 75.4 | 6.3 | |
| 7/12/23 | 410.6 | 77.1 | 11.0 | |
| 7/11/23 | 53.7 | 151.5 | 261.3 | 128.58 |
| 7/6/23 | 7.3 | 37.9 | 17.5 | |
| 6/29/23 | 135.4 | 42.0 | 34.1 | |
| 6/27/23 | 42.0 | 38.4 | 65.0 | |
| 6/22/23 | 18.7 | 5.2 | 39.7 | |
| 6/21/23 | 160.7 | 46.7 | 26.2 | |
| 6/20/23 | 2419.6 | 76.3 | 178.9 | |
| 6/15/23 | 53.7 | 70.3 | 2419.6 | |
| 6/13/23 | 18.3 | 20.1 | 71.2 | |
| 6/8/23 | 8.5 | 8.6 | 191.8 | |
| 6/6/23 | 40.4 | 20.1 | 9.6 | |
| 6/1/23 | 118.7 | 28.5 | 4.1 |
