ADDISON COUNTY — Addison County Riverwatch has released the latest numbers from its E. coli Monitoring Results in the New Haven and Middlebury Rivers.

The collaborative sampled for E. coli at four Addison County recreation sites on Tuesday, July 1. E. coli is a bacteria found in the intestines of humans and other warm-blooded animals. It is used as an indicator of potential fecal contamination of waters. While most strains of E. coli are themselves not pathogenic, detection of E. coli suggests that other disease-causing pathogens may be present.

The Vermont Department of Health sets a health-based safety standard for swimming at 235 organisms/100 mL of surface water. A water sample — taken as a snapshot — that contains a concentration of organisms/mL lesser than 235 is considered compliant with the safety standard for swimming.

Results on July 1 were as follows:

New Haven River

• Bartlett’s Falls (Bristol): 36 org/100 mL
• DeMers Park (New Haven): 20 org/100 mL

Middlebury River

• Route 125 Bridge (E. Middlebury): 12 org/100mL
• Shard Villa Road Bridge (Middlebury): 228 org/100mL

On July 1, 2025, E. coli concentrations at all sampling stations were compliant with safety standards. The reading at the Shard Villa Road Bridge was relatively higher in E. coli levels but still compliant with the safety standard. Based on past monitoring of these rivers, E. coli levels can become elevated after rain events. Those levels also can sometimes rise when weather is warm. In general, swimmers should avoid the river after significant or heavy rainfall

Riverwatch plans to post again after its Aug. 5 sampling. For more information, contact [email protected].