Sewer Backing up? We're here to help.

what to do

The flowchart below can be followed to help property owners and residents navigate through a sanitary sewer backup. We know this is a stressful event, and the Engineering Department is here to help you where we can.

Steps Residents should take when responding to a backup.

The Milwaukee Metropolitan Sewerage District requests that you notify them, in addition to the City of West Allis, of any backups at your property. 

If you've experienced any water in your basement, please let us know by completing the form on the Reporting a Wet Basement webpage.

Your sewer lateral

The plumbing inside your home is connected to the City's sanitary sewer through an underground pipe called a sanitary lateral. As the property owner, you own this pipe from inside your house to the connection point of the City's sewer in the road and are responsible for keeping it properly flowing and free from cracks, holes, and other defects. 

While the property owner is responsible for their private sanitary lateral, the sanitary sewer in the roadway is maintained and owned by the City. The diagram below helps show this distinction.

The ownership structure of sanitary laterals in the City.

should you flush it?

A friendly reminder from the Engineering Department that just because something CAN be flushed doesn't mean it SHOULD be.

Paper towels, napkins, "flushable" wipes, and many other personal hygiene products do not disintegrate like toilet paper! You may be creating costly clogs in your pipes and the communities sewer pipes. More information about what should and shouldn't go down your toilet can be found by watching the videos below or by visiting the What Not to Flush Down the Toilet webpage.


Backups can be an unpleasant and usually costly experience. To reduce the risk of experiencing a backup, you can:

  • Televise your sanitary lateral
    • This is the best way to determine the condition of your entire lateral
    • Inspection can reveal cracks, breaks, joint problems, and/or root intrusion
  • Use root treatment products
    • Tree roots are able to find their way into your lateral through cracks
    • Left over time, these roots block solids and can cause a build up of sewage
    • Products can be purchased at most hardware and home improvement stores
    • May need to hire a pipe cleaning specialist or a plumber to remove the roots completely
  • Avoid pouring fats, oil, or grease down the drain
    • Do not dispose of coffee grounds or other heavy solids down the drain
    • Pour into a coffee can or similar container, allow them to cool and solidify, and then deposit in the trash
  • Only flush the 3 P's
    • Do not flush wipes, diapers, or feminine hygiene products even if they are labeled "flushable"
    • So-called flushable products catch on lateral obstructions, such as roots or grease, and form clogs


Learn more about your sanitary lateral by visiting the Laterals webpage.

More information regarding the hazards that are created with a basement backup can be found on the Water in my Basement webpage.