A sewer backup is the one basement flood you cannot just pump out and forget. The water is contaminated, the cause is often outside your property line, and if you do not act within a few weeks you can lose the right to make the city pay. Here is what we tell homeowners in Macomb, Oakland and Wayne County when they call us with sewage in the basement.
First hour: safety
- Keep everyone out, especially kids and pets. Sewage carries bacteria and whatever else went down the neighborhood’s drains.
- Do not run water in the house. Every flush, shower and load of laundry goes to the same pipe that is already full and comes right back up.
- If water is near outlets or the furnace, shut off power to the basement at the panel, or have the utility cut it.
- Do not open the cleanout cap on the main line. People do this thinking it will relieve the backup. It just gives the sewage a bigger hole to come out of.
- Photograph everything before you touch it: the water line, the floor drain, damaged items, and the time and date.
Figure out which kind of backup you have
There are two, and they have different fixes and different people paying for them.
1. Your own line is blocked. Only your house backs up, it happens in dry weather too, and it often starts with slow drains and gurgling. Causes: tree roots, grease, a collapsed or bellied section of clay or Orangeburg pipe, or a broken lateral. The fix is on your property: hydro jetting to clear it, a camera inspection to see why it blocked, and sewer line repair or replacement if the pipe is broken. This commercial line in Warren backed up for years because of one bad repair:
2. The city main surged. It happened during or right after a heavy rain, your neighbors have it too, and water came up through the floor drain, a basement shower or toilet even though nothing was running. The public sewer took in more stormwater than it could carry and pushed back up every lateral connected to it. This is the type that flooded thousands of basements in Detroit, Dearborn and the Grosse Pointes in June 2021, and it hits older combined-sewer areas in southeast Oakland County (Royal Oak, Berkley, Huntington Woods, Birmingham and neighbors) and parts of Warren every few years. There is nothing wrong with your pipe. The fix is a valve that closes when the main pushes back.
Michigan’s sewer backup law: the 45-day rule
If the backup came from the public system, Michigan’s sewer backup statute (Public Act 222 of 2001) lets you claim damages from the city, county or drain district, but only if you give them written notice within 45 days of discovering the backup. Call your city’s DPW or water department the same day, ask for their sewer backup claim form, and send it in writing with your photos. You will need to show the public system had a defect the agency knew or should have known about, and that it caused your loss. Not every claim is paid, but a claim that misses the 45 days is not even considered. This is general information, not legal advice; a lawyer who handles these claims can tell you where you stand.
Insurance: check for the rider today
Standard Michigan homeowners policies exclude sewer and drain backup. Most carriers sell a “water backup and sump overflow” endorsement for roughly $40 to $150 a year. If you live in any of the neighborhoods above and do not have it, call your agent before the next storm. More in our article on what insurance covers.
Cleanup: this is not a wet-vac job
Sewage is category 3 water. Carpet, pad, drywall that got wet, particle-board furniture and anything porous that sat in it should go. Hard surfaces get washed with detergent and then disinfected. Dry the basement with air movers and a dehumidifier, and keep them running until the framing and slab read dry on a meter, usually three to five days. Our flood restoration crew does extraction, tear-out, disinfection and drying, and we are also the contractor that puts in the valve so it does not happen again.
The fix: a backwater valve on the main line
A backwater valve (sewer backflow preventer) is a one-way flap installed on your main sewer line, usually in the basement floor near where the line leaves the house. Water from your house flows out through it normally. When the city main surges and tries to push back, the flap closes and the sewage stays in the street. Here is one going in, along with a new sump system:
What the install involves: we locate the main line, open the floor, cut in the valve with an access cover so it can be checked and cleaned, and pour the floor back. Most are done in a day. Some cities in our area require a permit and an inspection for the valve; we handle that. A few things to know:
- While the valve is closed during a surge, your own drains cannot flow out either. Do not run water until the storm passes. For homes with a basement bathroom, we often pair the valve with a sewage ejector or an overhead sewer setup.
- The valve needs an occasional check to make sure the flap moves freely. We show every customer how.
- If your line is also full of roots or has a belly, a valve alone will not help. We camera the line first.
Full details on our backwater valve installation page.
Frequently asked questions
Why does my basement floor drain back up when it rains?
The city main is overloaded with stormwater and pushes back up your lateral. A backwater valve on your main line stops it.
Who is responsible for a sewer backup in Michigan?
If your own lateral is blocked, you are. If the public system surged, you may have a claim against the city or county under Public Act 222, but you must give written notice within 45 days.
Does homeowners insurance cover sewer backup?
Only with a water backup / sump overflow endorsement. Standard policies exclude it.
How much does a backwater valve cost in Michigan?
It depends on where the main line runs and how much floor has to come up; we quote it after looking, and estimates are free. Compared with one basement cleanup it is cheap.
Can a sewer backup happen with a sump pump?
Yes. A sump pump handles groundwater, not the sanitary sewer. Many homes in our area need both a sump system and a backwater valve.
Mansour’s Innovations is a family-owned waterproofing, excavation and plumbing contractor in Shelby Township, Michigan, serving Macomb, Oakland and Wayne counties since 2014. Owner Imad “Matt” Mansour has 20+ years in the trade and the crew has completed 1,600+ projects. Our waterproofing work carries a 25-year transferable limited warranty. Call or text (586) 345-7292 for a free estimate.