Downspout Disconnection

Why Should I Disconnect My Downspout?

During heavy rain, every downspout on your home can send 12 gallons of water a minute to the sewer system, which increases the risk of basement backups and sewer overflows. Disconnect and help keep excess water out of sanitary sewers.

Like many cities, the older portion of the City of Milwaukee and the Village of Shorewood is served by combined sewer systems that carry both rainwaters, also known as clear water, and household wastewater to the Metropolitan Milwaukee Sewerage District's (MMSD) treatment facilities.

A significant source of clear water within the combined sewer is from rain that falls on your roof and is collected by downspouts that are directly connected to the combined sewer system. During rainstorms, this clear water can overwhelm sewer pipes and MMSD's treatment plants which can lead to street flooding, basement backups, and sewage overflows directly into our neighboring waterways.

Some Downspouts Cannot be Disconnected

You'll need enough green space in your yard to drain water into the ground naturally. You do not want to create water problems for your neighbors or icy conditions on sidewalks, driveways, or roads. It's VERY important to check with your municipality to make sure you can legally disconnect and that you disconnect correctly.

Downspout Disconnection Programs

In an effort to reduce the amount of clear water that enters the combined sewer system during rain events, MMSD amended our Rules and Regulations to require the disconnection of downspouts at residential properties of four units or less in the combined sewer service area as long as the disconnections comply with the criteria set forth in the City’s plumbing code and MMSD’s Rules and Regulations. In order to comply with these rule changes, the City of Milwaukee has begun the ​​​​​Milwaukee Downspout Disconnection Program and the Village of Shorewood Downspout Disconnection Program. Check out Milwaukee's DPW tool to see if your home is in the combined sewer service area and read the Downspout Disconnection Program frequently asked questions and incentive program.

How to Disconnect Your Downspout 

Step 1: Contact your city or village to find out if you can legally disconnect.

Step 2: Measure 9" from where the downspout enters the sewer connection.

Step 3: Cut the downspout with a hacksaw.

Step 4: Cap the sewer pipe coming out of the ground. In most cases, you should be able to use a simple rubber cap secured by hose clamp. You can also use a wing-nut test plug.

Step 5: Insert the downspout INTO the elbow (if you put the elbow into the downspout, it will leak). You may need to crimp the end of the downspout with a pair of pliers to get a good fit.

Step 6: Attach a downspout pipe extension to carry water away from the house and foundation. You can use a hacksaw to cut the extension to the desired length. Be sure to insert the elbow into the extension to prevent leaks. Secure the elbow and extension with sheet metal screws. To prevent erosion where the water drains, you can place a splash block at the end of the downspout extension.

Disconnecting Your Downspout

Curious on how you can create a more sustainable home in Wisconsin? Try a rain barrel, rain garden or install natural landscaping.


For question on downspout disconnection or how to implement any of our green strategies, contact us.