West Interceptor Shorewood Relief

A relief is a new pipe that relieves capacity constraints in an existing interceptor. Relief pipes are typically parallel to and interconnected with the existing interceptor which remains in service. A replacement is when an existing interceptor pipe is abandoned and replaced with a new interceptor pipe. Reliefs are often preferred because multiple pipes provide a more flexible and resilient system.




The district’s West Intercepting System is a complex network of parallel sewers that provides service to the near west side of the City of Madison, the City of Middleton, the Village of Shorewood Hills and the Town of Westport. The original West Interceptor was built in 1916 and extended in 1932. There have been several extensions, reliefs and replacements added to the system over the years. There are currently three district interceptor pipes in the Shorewood Hills area. The 1932 West Interceptor and the 1971 West Interceptor Midvale Relief have adequate capacity for the areas they serve. The 1959 West Interceptor Relief is at or nearing its maximum capacity throughout the majority of the project area. The purpose of the current project is to relieve the capacity constraints in the existing 1959 West Interceptor Relief. 

The last upgrade to the West Intercepting System was the West Interceptor Campus Relief project which was constructed in four phases from 1999 through 2004. The upstream end of the Campus Relief project was on the east side of Walnut Street on the north side Campus Drive. The current project, the West Interceptor Shorewood Relief, is approximately two miles long. The downstream end is west of Walnut Street and north of Campus Drive in the Highland Street exit ramp. The upstream end is in Indian Hills Park.

The district and our consultant, Strand Engineers Inc., are early in the design process for the Shorewood Relief. Plans for the overall project are scheduled to be complete in summer 2020. Due to the length of the project it is anticipated that construction will take place in three phases. Construction of Phase 1 will begin in early spring 2021 and final completion of Phase 3 construction is anticipated to conclude in fall 2023.   

The West Interceptor Shorewood Relief project reflects the district’s efforts to maintain adequate system capacity to serve our customer communities and protect the environment.

For questions, contact Eric Hjellen, Madison Metropolitan Sewerage District project manager, erich@madsewer.org or 608-222-1201 ext 348.

Map of Project Location
West Interceptor System
Link to 10-21-19 Meeting Presentation