Most basements around Chicago have a small iron grate set into the concrete, usually somewhere near the furnace or the laundry tub. Then a summer storm stalls over the city for an afternoon, and that grate turns into the one opening in the whole house that water can use to get inside, rising up from below instead of falling from the sky.
Crews at Morning Noon Night Plumbing & Sewer, working out of Lyons and taking calls across the city and the western and southern suburbs at any hour, see a lot of basements like these every wet season. What they find tends to follow a pattern, and it is one any homeowner can learn to read.
One Pipe Doing Two Jobs Under the Bungalow
The story starts long before your house was built. The Chicago region was largely marshland, flat and slow to drain, and the sewers laid down more than a century ago were designed as combined systems. That means the water leaving your toilet and the rain pouring off the street travel through the same pipe. On a day with two inches of rain in two hours, the local sewer under your street fills faster than it can empty into the larger interceptors and the Deep Tunnel.
When that street sewer is full, the water inside it has nowhere to go but sideways and up. Your home’s sewer line connects to it with nothing in between, so the pressure pushes back along your lateral and looks for the lowest exit. In a typical bungalow or two flat, that exit is the basement floor drain, followed closely by a basement toilet, shower or laundry standpipe. More than three million people in the area live on combined sewers.
Signs the Sewer Is Talking to You
Backups rarely arrive without a warning. The trouble is that the warnings are small and easy to blame on something else. Watch for these.
- A gurgling sound from the floor drain or a basement toilet when an upstairs tub empties or the washing machine pumps out.
- Water pooling around the floor drain during heavy rain and then slowly disappears once the storm passes.
- A faint sewer odor in the basement that comes and goes with the weather.
- Several fixtures drained slowly at the same time, rather than a single clogged sink.
- A dark ring or silt line around the drain grate that wasn’t there last season.
Any one of these on its own may be minor. Two or three together usually point to a line that is partly restricted or a street sewer that surcharges often, and it is worth having someone look before the next big storm does the looking for you.
The Pipe Nobody Thinks They Own
Here is the part that surprises many people. The sewer line running from your foundation out to the main under the street, called the lateral, is generally the property owner’s responsibility. In older Chicagoland homes that lateral is often vitrified clay tile, laid in short sections with joints every few feet. Over decades those joints shift and crack, and tree roots find them.
A lateral that is half full of roots or grease can’t carry water away quickly even on a normal day, so during a storm it fills almost instantly. Mechanical rodding cuts roots and punches through blockages, which is usually the first fix. Hydro jetting uses high pressure water to scour grease and sludge from the pipe walls and tends to keep a line clear longer. Neither one tells you what shape the pipe is in, though, and that is where a camera inspection earns its cost. A video run through the lateral shows offset joints, bellies where water sits, cracked sections and the exact distance to any problem. That footage decides between scheduled rodding and relining or replacement.
Closing the Door From the Inside
Clearing the line helps your house drain. It does nothing to stop a full street sewer from pushing water back in. For that, the plumbing itself has to change, and most Chicago area homes end up with one of three approaches.
- A backwater or check valve. This is a one way flap installed on the main line that closes when water tries to flow backward. It is the least invasive option, but it needs periodic cleaning, and while it is closed nothing in the house can drain either, so running the washer during a storm can flood you from your own side.
- An overhead sewer conversion. The basement floor drain is sealed off, and everything below grade drains into a sealed ejector pit. A pump lifts that water up to a new line that leaves the house above the level the street sewer can reach. It involves concrete work, but it is widely considered the most reliable option where backups are frequent.
- A sump and ejector setup with backup power. Foundation water and basement fixtures are handled by pumps, and a battery or water powered backup keeps them running when storms knock out electricity, which is exactly when they are needed most.
Some municipalities in Cook and DuPage counties have offered cost sharing programs for flood control work at various times, so it is worth calling your village hall before committing to a design. Permits are usually required.
Giving the Street Sewer a Little Breathing Room
Not every fix lives inside the basement. Roof downspouts connected straight into the sewer are one of the biggest sources of extra water during a storm, and the region’s water agency lists disconnecting them as the easiest step a homeowner can take. Its page on helping reduce flooding also encourages holding off on laundry, dishwashers and long showers before and during heavy rain, since every gallon you skip is room the sewer can use for storm runoff.
Habits matter on the inside of the pipe too. Wipes labeled flushable don’t break down the way toilet paper does, and cooking grease poured down the sink cools into a coating that catches everything behind it. Both make a narrow old lateral narrower.
If the Water Comes Up Anyway
Even a well protected basement can take on water in an extreme event. If it happens, stop using water upstairs right away so you aren’t adding to the problem. Keep away from standing water near outlets, appliances or the furnace, and shut off power to the basement from a dry location if it can be done safely. Water that comes up through a floor drain is sewage, not rainwater, so drywall, carpet and anything porous it touches generally needs to be removed rather than dried out.
Take photos, and check your homeowners policy for a sewer backup rider, because standard coverage often excludes it. Once the water is gone, the most useful thing you can do is find out why it came in. A camera inspection after the cleanup turns one bad afternoon into a clear plan, and the floor drain goes back to being just a grate in the concrete.