St. Louis homeowner guide. By Gutter Installation St. Louis, a referral service. Updated November 3, 2026.
No. The Metropolitan St. Louis Sewer District lists downspouts among the stormwater connections to building laterals that break its Sewer Use Ordinance and local building codes and must be removed. If it identifies one, it sends a letter. In project areas, it says it will remove significant connections at no cost and without penalty for a limited time, with the owner's signed agreement.
- A downspout shouldn't go into a sanitary lateral.
- Old houses often have pipes in the ground, so find out where yours lead.
- MSD says it prefers to work with customers.
- Don't tie new gutters into a pipe nobody has traced.
Why MSD cares
Stormwater that enters wastewater lines takes up room meant for sewage, and that can contribute to backups and overflows in heavy rain. MSD Project Clear names downspouts, sump pumps, stairway and driveway drains, yard drains and uncapped cleanouts as connections that can send stormwater into the wastewater system.
How to tell if yours is connected
- Look at each downspout's end. Does it enter a pipe at the ground?
- See if the pipe surfaces anywhere else, such as a curb, a ditch or a yard outlet.
- Ask a plumber or a sewer contractor about a camera or dye test, which is the way to be sure.
- Check any old inspection reports from when you bought the house.
If you get a letter
Read it carefully and contact MSD directly. MSD says that if a stormwater connection is identified, it sends a letter, and that the connection must be removed. In project areas, it says owners receive disconnection agreements to sign and return, and that it will remove significant connections for a limited time at no cost and without penalty. Don't hire anyone for this until you know whether that program applies to you.
What replaces the connection
- Cap the old pipe at the ground, properly, and don't leave it open.
- End the downspout in an elbow and extension that sends water away from the wall.
- On a tight city lot, re-route toward the rear or a paved surface that drains away, keeping neighbors in mind.
- Where there's room and fall, a separate buried line to a suitable outlet may work. Ask your city first.
Watch for the side effect: water that used to vanish now lands on your lot. Look at grading, basement walls and icy walks. Downspouts and drainage covers the options.
Outside MSD's area
St. Charles County has different sewer providers, so ask yours. The basic principle of keeping stormwater out of sanitary sewers is common, but the program details aren't.
FAQ
Is it illegal to have my downspout in the sewer?
MSD says these connections break its Sewer Use Ordinance as well as local building codes and must be removed. It also says it prefers to work with customers, with enforcement as a fallback. Contact MSD with questions about your property.
Will MSD pay to disconnect it?
In project areas, MSD says it will remove significant connections at no cost for a limited time if you sign the agreement. Outside those, don't assume. Ask MSD what applies to your address.
Can my sump pump go to the sewer?
MSD lists sump pumps with downspouts as connections that shouldn't go to the sanitary system. Ask a plumber about a legal discharge point.
Should a gutter contractor do this?
A gutter contractor can re-route downspouts above ground. Testing and capping lines is often plumber's work. Ask each what they handle, and make sure someone owns the whole job.
Sources
Related
- Downspouts & Drainage
- Gutter Installation
- Gutter Replacement
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General information for St. Louis-area homeowners. Not a quote, and not engineering, legal or insurance advice.