Sewer Backup in the Basement: What to Do in the First Hour

A sewer backup in basement areas is a health hazard and a plumbing emergency. In the first hour, your job is simple: stop all water use, keep people and pets away, cut power to wet areas if you can do it safely, and call a plumber. Do not try to clean raw sewage or open the main cleanout yourself. Our 24/7 sewer backup repair team can clear the line while you focus on keeping your family safe.

Sewage on the floor right now? Call Priority Plumbing Services at (618) 207-1647. We answer day and night across the Metro East.

Key Takeaways

• Stop the water first. Every flush, shower and laundry load adds more sewage to the basement.
• Treat the water as contaminated. Sewage carries bacteria and viruses. Gloves, boots and a mask are the minimum.
• Electricity and standing water do not mix. Only shut off power if you can reach the panel without stepping in water.
• Document everything. Photos and video before cleanup help with insurance and with finding the cause.
• Find out whose pipe failed. A clog in your sewer lateral is yours to fix. A surge from the city main is handled differently.

Minute by Minute: Your First Hour After a Sewer Backup

Panic makes people do the wrong thing first. Work through this list in order. It protects your health, limits damage, and gives your plumber the information needed to fix the cause.

Minutes 0 to 5: Stop the flow

1. Tell everyone in the house to stop using water. No flushing, no showers, no dishwasher, no washer.
2. If the washer or dishwasher is running, pause it.
3. Keep children and pets out of the basement and close the door.

Minutes 5 to 15: Make the area safe

1. If water is near outlets, cords, a furnace or a water heater, shut off power to the basement at the breaker panel. Only do this if the panel is in a dry spot you can reach without touching water.
2. If you smell gas, leave the house and call your gas utility from outside.
3. Open basement windows for air if it is safe to reach them.

Minutes 15 to 30: Document and call

1. Take photos and video of the water, the drain it came from, and anything damaged.
2. Call a licensed plumber. Tell them which drains backed up, whether it is raining, and whether neighbors have the same problem.
3. Call your homeowners insurance company and ask whether your policy includes sewer or water backup coverage.

Minutes 30 to 60: Protect what you can

1. Wearing gloves and boots, move clean items off the floor and upstairs.
2. Do not run a household vacuum or shop vac on raw sewage unless it is rated for it.
3. Wait for the line to be cleared before starting any real cleanup. Cleaning while the drain is still backing up just repeats the work.

Why Sewer Backups Happen in Metro East Basements

Sewage comes up through the basement floor drain because it is the lowest point in the plumbing. When the pipe leaving your house cannot carry wastewater away, it rises there first. The main causes are:

• Main line clogs from grease, wipes, paper towels and feminine products.
• Tree roots growing into the joints of older clay and cast iron sewer pipe.
• Collapsed or sagging pipe where soil movement has cracked or bent the line.
• Heavy rain that fills the city sewer and pushes water backward into homes.
• A failed sewage ejector pump in homes where the basement bathroom drains to a pump pit.

The U.S. EPA notes that sanitary sewer overflows can back up into homes when sewers are blocked, damaged, or overwhelmed by rain and groundwater. When that happens in the public main, your home is on the receiving end even if your own pipe is fine.

Clue	Points to	Who usually fixes it
Backup on a dry day with normal water use	Clog or damage in your sewer lateral	Homeowner, through a licensed plumber
Backup during heavy rain, neighbors affected too	Overloaded city or village sewer	Contact the municipality, consider a backwater valve
Only the basement bathroom backs up	Sewage ejector pump or its check valve	Homeowner, through a licensed plumber
Backups every few months	Roots, a belly, or an offset joint	Homeowner, after a camera inspection
Water appears at the cleanout outside	Blockage between the house and the street	Plumber first, then the city if it is in the public main

What Not to Do During a Sewage Backup

A few common mistakes turn a bad day into a worse week:

• Do not pour chemical drain cleaner into the drain. It will not clear a main line blockage and it splashes back on whoever opens the pipe.
• Do not open the main cleanout cap. If the line is full, sewage under pressure can pour out of it.
• Do not walk through standing water near electrical outlets or appliances.
• Do not keep “testing” the drain by flushing to see if it cleared.
• Do not save soaked carpet, drywall, insulation or cardboard. Porous materials that touched sewage cannot be fully cleaned.

How a Plumber Clears and Diagnoses the Line

Once we arrive, the first goal is to get the line flowing so the water drains. The second goal is to find out why it clogged so it does not happen again.

1. Locate the cleanout and confirm where the blockage is.
2. Clear the line with a powered cable or water jetting, depending on what is in the pipe.
3. Run a camera down the line to look for roots, cracks, bellies and offset joints.
4. Show you the video so you can see the problem, not just hear about it.
5. Explain your options, starting with the least invasive fix that will actually work.

A sewer line camera inspection is the step most homeowners skip, and it is the one that prevents a repeat. If the camera finds a cracked or root-filled section, our sewer line repair team can often fix that one spot instead of replacing the whole line.

Not sure if your backup needs a plumber tonight? If sewage is on the floor, the answer is yes. Call (618) 207-1647.

Cleaning Up Safely After the Line Is Clear

Sewage cleanup is dirty, physical work. Small backups on a concrete floor can often be handled by the homeowner with the right gear. Large backups, finished basements, or water that sat for more than a day are better left to a water damage restoration company.

If you are cleaning a small area yourself:

1. Wear rubber gloves, boots, eye protection and an N95 mask.
2. Remove standing water with a wet/dry vacuum rated for it, or a pump for deeper water.
3. Bag and discard porous items that were soaked.
4. Scrub hard surfaces with hot soapy water, then disinfect.
5. Dry the space with fans and a dehumidifier. Mold can start in 24 to 48 hours in a damp basement.
6. Wash your clothes separately and wash your hands well when finished.

The Massachusetts Department of Environmental Protection has a practical sewage backup cleanup guide for homeowners that covers cleanup, disinfection and when to throw items away.

How to Prevent the Next Sewer Backup

Once the line is clear and the basement is dry, take steps so you are not doing this again next spring.

Prevention step	Protects against	Good for
Backwater valve on the sewer line	City sewer surges during storms	Homes that back up when it rains
Routine drain cleaning	Grease and paper buildup	Older homes and busy households
Root treatment or hydro jetting	Root growth in clay or cast iron pipe	Lines near mature trees
Spot repair or trenchless lining	Cracks, bellies and root entry points	Lines that keep backing up
Ejector pump service	Pump failure in basement bathrooms	Homes with a sewage pump pit

Daily habits matter too. Keep grease out of the kitchen sink. Flush only toilet paper. Do not connect downspouts or sump discharge to the sanitary sewer. Those three habits prevent a large share of the sewer backups we see in homes from Edwardsville to Greenville.

Sewer work in Illinois must be done by a licensed plumber. You can check any license through the Illinois plumbing license program run by the Illinois Department of Public Health. Our owner, Kyle Gruner, is a Master Plumber with Illinois license 055-045366.

Sewer Backup in Basement: FAQs

What should I do if I find a sewer backup in my basement?

Stop all water use in the house, keep people and pets away, and shut off power to the basement only if you can reach the panel without touching water. Take photos, then call a licensed plumber to clear the line. Call your insurance company the same day.

What is the sewer drain in the basement called?

The opening in the basement floor is the floor drain. The capped pipe fitting you may see on the wall or floor is the main cleanout. Plumbers use the cleanout to reach the main sewer line, also called the sewer lateral, that runs to the street.

How much does sewer backup cleanup cost?

It depends on how much water came in, how long it sat, and what it touched. A small backup on bare concrete costs far less than a finished basement with carpet and drywall. Clearing the line is a separate plumbing cost. Ask for pricing before work begins.

Why is my basement floor drain backing up with sewage?

The main sewer line is blocked, damaged, or overloaded by the city sewer. Because the floor drain is the lowest opening in the house, sewage comes up there first. A plumber needs to clear the line and check it with a camera.

Does homeowners insurance cover a sewer backup?

Many standard homeowners policies do not include sewer or water backup coverage unless you add an endorsement. Coverage varies by insurer and policy. Call your agent and ask directly, ideally before you ever need it.

Is it safe to stay home during a sewer backup in basement areas?

Usually, as long as you stay out of the wet area, keep children and pets away and do not run any water. Leave the house if the smell is strong, water reaches outlets or you smell gas.

How long does sewer backup cleanup take?

Clearing the line often takes a few hours. Sewer backup cleanup and drying out the basement can take several days, depending on how far the water spread and what got wet.

How do I stop a sewer back up in basement drains from happening again?

Find the cause with a sewer camera inspection, then fix it. That may mean root removal, a pipe repair or a backwater valve. Regular drain cleaning helps if grease or buildup caused the backed up sewer in basement drains.

Call a Licensed Plumber Before You Start Cleanup

Cleanup can wait an hour. Clearing the line cannot. Call Priority Plumbing Services at (618) 207-1647 and we will clear the sewer line, check it with a camera, and show you exactly what caused the backup.

Pricing is discussed before work begins, every job comes with a 1-year warranty, and we answer 24/7. We serve Pocahontas, Highland, Greenville, Edwardsville, Glen Carbon, Maryville, Troy and nearby Metro East towns. You can also contact our plumbing team online.