The City of Madison Public Sanitary Sewer System is made of nearly 790 miles of gravity pipe connected by 20,000 sanitary access structures and is supported by 29 pumping stations. The City of Madison Engineering Division is responsible for operating and maintaining this system to safely convey 28.1 million gallons of raw sewage per day from Madison homes and businesses to the Nine Springs Wastewater Treatment Plant owned and operated by Madison Metropolitan Sewerage District, which is separate from the City of Madison Sewer Utility. MMSD is not a City of Madison agency. Maintaining this system in good operating conditions is essential to the health of our citizens and environment.

Homeowners are responsible for the maintenance and repair of the private sanitary sewer service line. The private sewer service extends from within the home to the point where it connects to the public sanitary sewer main.

Homeowner Responsibility infographic

Preventative Maintenance

Homeowners can do easy things every day to take care of the private pipes they are responsible for and backups can be avoided.

  • Do not plant trees and/or shrubs over private building sewer pipe. The roots of trees, particularly Silver Maple and Willow trees, will seek out the joints of the sanitary sewer and clog the pipe.
  • Do not put large amounts of vegetable waste, like pea pods and tomato skins through the garbage disposal at one time.
  • Do not dump large amounts of grease and paint. If a grease trap is required, clean the trap regularly.
  • Keep lint traps in the sinks.
  • Follow the guidelines in our "Do Not Put Down The Drain" list.

Unplugging or cleaning sediment from your sewer lateral every 1-3 years is not unusual. However, if a homeowner has to have the building sewer cleaned more often than annually, they should contact the City of Engineering Division to find out if a bigger problem is causing the blockages. Homeowners who have a backwater valves on their sewer laterals inside of the home or in the yard, need to plan to maintain the backwater valve to make sure that it continues to operate effectively. 

If you do not have a backwater valve and you are interested in getting one installed, the City has a pilot program policy to reimburse property owners to install them. We recommend homeowners to install them if they have had a history of sewer backups.