Commonwealth Interceptor Upgrade Project


Commonwealth Interceptor Upgrade Project

AlexRenew is upgrading a portion of the Commonwealth Interceptor to address capacity issues from excess infiltration and inflow.

The Commonwealth Interceptor is a separate sanitary sewer — owned and operated by AlexRenew — that collects sanitary sewage from the City of Alexandria’s separate sanitary sewer system within the neighborhoods of Del Ray, Rosemont, and North Ridge (known as the Commonwealth Separate Sanitary Sewer Area). 

Sewage collected by the Commonwealth Interceptor is directed to AlexRenew’s wastewater treatment plant in Alexandria’s Southwest Quadrant for purification before being returned to the Potomac River. The Commonwealth Interceptor has sufficient capacity to convey these sanitary sewer flows to AlexRenew. However, during periods of intense rain, the Commonwealth Separate Sanitary Sewer Area (owned by the City) is overwhelmed by excess infiltration and inflow which exceeds the Commonwealth Interceptor’s capacity, causing separate sanitary sewer overflows (SSO’s). 

The Commonwealth Interceptor Upgrade Project will address this problem by increasing the diameter of the Commonwealth Interceptor to 48 inches between Duke Street and Braddock Road (shown in the map below). To learn more about the project, download the flyer below. 

Location of Commonwealth Interceptor Upgrade Project

CIP Service Map
Click on Image for Full View





Flyer for Commonwealth Interceptor Upgrade Project              

Flyer Thumbnail




Flyer for Commonwealth Interceptor Upgrade Project: Field Surveying

Heads Up: Field Surveying
Updated flyer about field surveying.




VIDEO: How Excess Infiltration and Inflow Causes Capacity Issues in the Commonwealth Interceptor