Sanitary Sewer Overflow from Colchester Ave Outfall - June 18, 2024



On June 18, 2024 at approximately 12:20 PM, a blockage of improperly disposed heavy duty paper towels (“shop towels”) and other improper paper products caused a sanitary sewer overflow to occur just upstream of the Salmon Hole Park on the Winooski River.   The debris was inadvertently released and traveled further downstream where it became lodged when crews were performing maintenance on flow monitoring equipment in a sewer access structure that was not functioning due the debris.

Photo of blockage removed from City sewer line.

Approximately 8800 gallons of sewage were released to the River before the blockage could be fully removed at approximately 1:46 pm.  As a result of City staff efforts to pump and haul waste approximately 7400 gallons were prevented from discharging into the Winooski River.  The image below shows the SSO discharge point (red circle), and the one mile downstream flow from that point. 

To inform the public, we have posted signage at public access areas along the Winooski River within one mile of the discharge point, alerted the Vermont Department of Environmental Conservation and reached out to the City of Winooski and Winooski Valley Park District.  

Given the discharge volume compared to the volume of the Winooski River, we do not anticipate a significant risk to public health. Those with compromised immune systems, and young children, should avoid recreating at or within 1 mile of the downstream portion of the Winooski River. We will leave the signs up for 48 hours from the end of the inadvertent discharge and remove them on 6/20.  

City residents are encouraged to review best practices for disposing of waste – and helping avoid unnecessary sewer clogs - at .  This overflow could have been prevented by property owners making better decisions about what they put down the toilet.  

The Water Resources team will be reviewing the incident to understand how the equipment maintenance could have been performed differently to prevent the dislodging of the “rag” ball. 



Press Release Date: 
City Department: 
Public Works Department