Madison Launches Sanitary Sewer Study to Support Growth and Long-Term Infrastructure Planning

Carollo Engineers to lead first project under Madison’s new Sanitary Sewer Study Program, helping the city strengthen stormwater resilience

MADISON, Wis.– The City of Madison is taking a proactive step to strengthen its wastewater infrastructure by initiating the Campus, Downtown, and East Washington Ave Sanitary Sewer Study. Using sanitary sewer modeling, the study will assess existing system performance, evaluate the impacts of proposed development and redevelopment, and identify improvements required to maintain reliable service as the city grows. North America’s premier water engineering and consulting firm Carollo Engineers has been selected to lead the effort.

Madison is experiencing rapid population growth and redevelopment of properties throughout the city, particularly along major transit corridors, increasing demand on the wastewater collection system. To plan strategically for long-term infrastructure needs and support efficient, consistent review of future projects, the City is launching a new Sanitary Sewer Study Program, with the Campus, Downtown, and East Washington Ave corridor as its first study area.

“This program reflects Madison’s commitment to responsible infrastructure stewardship as our city continues to grow,” said City of Madison Engineering Division City Engineer Jim Wolfe. “By taking a corridor-based approach, we can better anticipate needs and keep wastewater service reliable for residents and businesses. The Campus, Downtown, and East Washington Ave corridor is the right place to start, and we look forward to expanding this program across the city.”

The study will develop a calibrated sanitary sewer model for the study area to assess current capacity and inform infrastructure investment decisions. While not the main objective, the work could also help the City better understand wet-weather impacts and identify opportunities to reduce stormwater entering the sanitary sewer system, helping minimize overflows, treatment costs, and improve resilience during extreme weather. The scope includes review of existing records and GIS data; developing a three-month monitoring plan; calibrating the model with flow and system performance data; and preparing capacity assessment maps. In leading the study, Carollo will also assist the City in creating a modeling guidance document to standardize methods for future sanitary sewer studies across Madison.

The result will be a practical planning tool that helps the City stay ahead of growth, bring consistency to development review along the corridor, and make more informed long-term capital investment decisions.

“We congratulate the City of Madison on launching its new Sanitary Sewer Study Program and taking a proactive, data-driven approach to planning for growth,” said Carollo Stormwater Technical Practice Lead Caroline Burger. “We look forward to partnering with City staff on a study that is not only technically rigorous but also designed to be practical and actionable, supporting consistent development review today and sound capital planning for years to come.”

Now underway, the Campus, Downtown, and East Washington Ave Sanitary Sewer Study is expected to be completed by summer 2027.