How to Clean Sewage Backup in the Basement: 15 Critical Steps

By: Diana Rodriguez-Zaba
Updated on: March 25, 2024

Whether it comes up through floor drains or backs up into sinks, you smell it first. The stench of sewage in the basement is unmistakable. Once you figure out the cause and address repairs, you’re still facing an unhealthy mess.

Do you know how to clean sewage backup in the basement?

You need to be prepared. This guide walks you through everything you need to know to tackle this mess.

Let’s start now.

What Causes Sewage Backup in the Basement?

sewage backup in chicago basement

There are four main reasons why sewage is backing up into your basement.

Some of these are outside of your control, but knowing that these causes exist can help you identify the problem that much faster.

  1. Clogs. This is the blockage problem that is the most preventable because a clog is caused by something that went into one of your drains or toilets. It could be food, hair, grease, paper, debris, or any other solid matter or object that becomes trapped in your pipes.
  2. Damaged Sewer Lines. If your pipes are older, it is possible that they have rusted through or cracked. This is especially true if you have metal or clay pipes
  3. Overgrown Tree Roots. Under the surface, tree roots can break, dislodge, or even grow through your sewer lines.
  4. Flooding. If there is more rain than the city’s drainage system can handle, then there may be a backflow of water into your home. 

What Are the Signs of Sewage Backups in Basements?

Wastewater will back up into your basement first because it has the lowest drains in your house.

But if you know what to look for, you will be able to spot an impending sewer problem before it becomes a major catastrophe.

  • Foul smells coming from your drains. Your drains and pipes are designed to carry wastewater and smells away from your home. If there are persistent sewer odors, that is a certain telltale sign.
  • Bubbling toilets or drains. This is a major red flag that wastewater is not flowing through your pipes as efficiently as it should.
  • Multiple slow or clogged drains or toilets. When you are seeing slow draining or blockage issues throughout your house, that is an indication that your main sewer lines are backing up.
  • Standing water or water coming out of a sewer cleanout pipe. When the capped pipe that grants direct access to your sewer line has water coming out of it, that usually means your sewer is stopped up.
  • Strange fixture issues. If you use the washing machine and your toilet bubbles, or you flush the toilet and water backs up into your shower, those are primary symptoms of a sewer blockage. 

What to Do Immediately After a Basement Sewer Backup

Before beginning your sewage cleanup project, take care of these important details.

  • Make it very clear that no one is to enter the affected area. This includes anyone with existing medical issues as well as children and pets. Let everyone know you’ll give the all-clear when you’re done.
  • Open as many windows as possible right away. This helps improve the air quality inside, but plan on closing them later. You’ll want to control the humidity while you work on cleaning up the sewage spill.
  • Pre-treat flooded areas with small splashes of chlorine bleach. This creates an initial disinfectant barrier that helps slow down the spread of sewage-borne bacteria.
  • Call your insurance company. If your policy carries a rider for sewage backup, explain what happened. If not, ask about your current coverage for general water damage.

How to Clean Up Sewer Backup in the Basement

sewage in basement

Knowing how to clean up raw sewage in the basement starts with understanding the risks. Utility lines coming into a wet basement can be very dangerous.

If you have any doubts about your safety, contact your city’s utility company immediately, and have them shut off your electricity and gas.

If sewage backup hasn’t affected basement connections and outlets, follow these 10 cleanup steps. Our guidelines are meant for small jobs only.

1. Protect Yourself First

Sewage cleanup exposes you to highly contaminated black water, so suit up in personal protection gear before you get started. You’ll need rubber gloves and boots, goggles, a face mask and water-resistant coveralls.

2. Protect the Rest of the House

Close off doors between contaminated areas and rooms that aren’t affected. This reduces the chance of tracking sewage debris and water through the house. It also minimizes the spread of airborne contaminants.

3. Identify and Drain

source of sewer backup

Identify the problem that caused the sewage backup. If you can’t handle repairs, call a professional right away. If the sump pump is operational, back it up by removing water with buckets or a large-capacity shop vac.

4. Clear Out Everything

Move out everything affected by sewage water. Address sludge and debris left behind with push brooms and shovels. Clear away as much as possible. You want to expose all surfaces that need cleaning and disinfecting.

Power Tip: Bag and seal items that need to be sanitized, and transfer them to a secure place for cleanup later.

5. Be Ready to Shovel

Sewage backups often leave behind sludge and debris that should never be cleared by hand. Instead, use a shovel to get it off the floor and into heavy-duty plastic bags. Dispose of the contaminated material right away.

If a surface has been in contact with sewage water, it has to be sanitized. Disinfect washed and rinsed basement areas by treating them with a mixture of 1 cup of bleach and 1 gallon of water.

6. Pull Up Flooring

Pull up all flooring contaminated by sewage water and debris. Securely bag vinyl, carpet and padding for immediate disposal. If you need help with this part of the job, make sure you have enough PPE to share.

7. Finish With a Wet Vac

wet vacuum for sewage cleanup

If you have electricity in the basement, remove remaining dirty water with a wet vac. Only use the equipment if you can plug it into a grounded outlet. Make two or three passes over all areas

Power Tip: Don’t dispose of contaminated water down drains. Instead, dump wet vac contents into a toilet.

8. Scrub and Rinse

Scrub down all surfaces affected by sewage backup. Basement floors, walls and steps need to be washed with hot water and a low-sudsing detergent and rinsed with clear, hot water

Power Tip: Increase efficiency and minimize contamination by working areas from top to bottom.

9. Sanitize All Surfaces

If a surface has been in contact with sewage water, it has to be sanitized. Disinfect washed and rinsed basement areas by treating them with a mixture of 1 cup of bleach and 1 gallon of water

Power Tip: For best results sanitizing floors, use a large, sturdy push broom instead of a mop.

10. Check the Sump Pump

Make sure the sump pump is still in good working condition. A sewage backup in the basement can overwork and even shut down the equipment.

If you’re not comfortable with DIY sump pump maintenance, bring in a professional.

11. Start the Drying Process

If the weather isn’t too humid, open windows in affected areas. Set up large fans so that they create crosscurrents of fresh air. Consider renting a heavy-duty dehumidifier. The drying process can take several days or longer.

12. Get Yourself Cleaned Up

Thoroughly wash down and sanitize your protective gear. Don’t try to save wet clothes or cleaning rags. Dirty items can contaminate other belongings. Take a hot shower, and use plenty of antibacterial soap or body wash.

13. Start Drying the Basement

If the weather cooperates, open basement windows. Position box fans in corners to create cross-ventilation, and set up a heavy-duty dehumidifier. Give the drying process at least three days to finish.

14. Arrange for Inspections

Contact a licensed electrician, plumber, and water damage professional, like ServiceMaster Restoration by Zaba in Chicago, IL. 

Arrange a time for each to inspect your home. The damage from a sewage backup often causes problems you can’t see, so don’t take any chances.

15. Check for Mold

Sewage backup in the basement creates ideal conditions for a bad outbreak of unhealthy mold. As well as you clean up the mess, traces of moisture and contaminants can continue to feed unhealthy fungal growth.

Regularly check the basement for mold after any type of downstairs flooding.

What Should I Do With Exposed Furniture, Clothing and Food?

sewage damaged belongings

Salvaging belongings from a flooded basement is very difficult, but it’s not impossible. You must determine which consumable goods have come into direct contact with sewage water and contaminated debris.

That’s a big job in an unfinished basement, especially when you start sorting through things stored downstairs.

It’s even more difficult in a finished basement. Items that can be salvaged must be treated carefully, so follow these guidelines.

1. Carpet and Furnishings

Basement flooring and furniture that have been slightly affected by a sewage backup can sometimes be recovered. However, it’s not a DIY project. Contact an industry-certified water damage restoration company.

2. Basement Appliances

Don’t assume appliances, laundry equipment or the furnace will work after being cleaned. Confirm their condition with inspections and repairs performed by licensed professionals.

3. Clothing and Bedding

Fabrics with minimum exposure to basement flooding can be washed by adding 1 cup of chlorine bleach per load. If the weather permits, finish by drying salvaged fabrics outside.

4. Valuable and Personal Belongings

Let your restoration pros take care of belongings that hold sentimental or monetary value. For example, our teams here at ServiceMaster by Zaba can often salvage water-damaged photos, artwork and computer equipment.

5. Canned Food Items

Canned food stored in the basement must be closely inspected before deciding on whether to keep it.

If the cans aren’t damaged or dented, give them a 15-minute soak in 1 gallon of water mixed with 1 ounce of bleach. Thoroughly scrub each can, and air dry. Throw away all other types of food items.

When to Call in the Professionals

sewer cleanup expert

Your health is a critical factor in deciding when to call in a certified restoration company.

If you face any of these situations in a basement flooded with sewage, immediately call in the pros.

  • Ruined Flooring – A sewage spill ruins the flooring in a finished basement. You can pull it up, but you have to do the work while wearing full PPE. The materials must be bagged and transferred to a safe disposal site. Whether it’s vinyl, hardwood or carpet, this job is usually too big for most homeowners.
  • Sewage Spread – Sewage backup in the basement often affects other areas of the house. For example, contamination can be accidentally tracked upstairs. DIY disposal can result in spills in other rooms. If the damage spreads beyond your basement, don’t take chances. Let professionals address sewage cleanup.
  • Exposure Time – Sewage backups can happen in the middle of the night or while you’re at work. Dangerous bacteria breeds very fast, so don’t try to take care of a sewage backup more than a few hours after it occurs.
  • Compromised Equipment – Often, furnaces and air handlers are located in the basement. If the equipment is affected by a sewage spill, its components are compromised. For example, the system’s ductwork must be professionally cleaned to prevent contaminated air from circulating through your home.
  • Insurer’s Recommendation – Homeowners insurance doesn’t cover sewage backups, but your policy may have a backup rider. In this case, your agent can recommend a restoration professional. For example, here at ServiceMaster by Zaba, we’re listed as a Quality Restoration Vendor with multiple insurers. We’re often recommended to property owners dealing with basement sewage backup.

How Do You Get Rid of Sewer Smell in the Basement after a Flood?

If your basement still smells like sewage even after a thorough cleaning, the most likely culprits are your pipes, vents, or drains.

This means that the first thing you must do is identify the specific source (or sources) of the offending odor.

1. Water Trap 

There are two ways that the traps in your basement’s floor drain could cause a foul smell in your basement.

First, they could still contain sewage or solid waste that was missed during clean-up.

Second, with a shop vacuum, all of the water in the floor trap could have been sucked out. Because the water acts as a protective barrier, a dry floor trap can release foul odors.

SOLUTION: If sewage or solid waste is present, remove the mass and flush the trap with hot water and a mild detergent. A dry trap only needs the flush. The clean water will block the smell.

2. Cleanout Plug

A cleanout plug is the device that controls the flow of wastewater and sends it down the sewage pipe. If it is broken or missing, sewer gasses will flow back into your basement.

SOLUTION: Remove the drain grate and inspect the cleanout plug to see if it is in good repair. If necessary, purchase and install a new one.

3. Check Your Appliances

Your heavy appliances and fixtures can often produce sewer smells. This would include washing machines, HVAC systems, water heaters, toilets, and sinks. Search for the source of the sewer smell in your basement by inspecting for improper venting, clogs, leaks, broken or dry traps, or broken seals.

SOLUTION: Fix any mechanical or plumbing problems you find. Clean and flush the area with hot water, mild detergent, and bleach.

For water heaters, the solution is a bit different. If the sulfur-like sewer smell results from a buildup of bacteria, you will need to put hydrogen peroxide in the tank to disinfect it.

The process is simple. Turn off your water heater’s cold water supply and drain some of the hot water from the tank. Disconnect the supply line and, using a funnel, add one cup of hydrogen peroxide for every ten gallons of water in the water heater. Reconnect the line, turn the water back on, and simply wait a few hours before using the unit again.

5. Use a Cleaning Solution

While there are products you can buy that are advertised to kill sewer smells, in most cases, you can solve the problem with what you already have on hand.

Hot water, ordinary antibacterial household cleaners, and bleach are your go-to options and will handle most stains and smells. Vinegar is also a wonderful natural cleanser and disinfectant that will eliminate most sewer smells.

One easy way to keep your pipes clear and odor-free is to pour a one-quarter cup of baking soda down the drain, followed by one cup of vinegar. Seal the drain, wait 30 minutes, and then flush the drain with hot water. 

If the smell does not go away, or if you see mold or mildew at any time, call a professional immediately.

How to Prevent Sewage Backup

The best way to clean the sewage out of your basement is to prevent the disaster from happening in the first place. Here are a few helpful prevention tips:

  • If your basement does not already have a working sump pump, buy one or repair the one you already own.
  • NEVER pour cooking oil or grease down any drain or toilet. It will solidify in your pipes and create a nightmare plumbing scenario.
  • NEVER try to flush feminine hygiene products down the toilet. They are even worse because unlike grease, they cannot be dissolved.
  • Install debris screens in your kitchen sink and hair traps in your showers, bathtubs, and bathroom sinks.
  • If you ever see any of the warning signs we listed above, address the problem IMMEDIATELY, before the worst happens.

Dealing with Sewage Backup in the Chicago Area? We Can Help

Our guidelines are meant for small projects, but some cleanup jobs are just too much even for the bravest DIY warrior. Sewage spills in the basement is a hazardous challenge, and poses many health risks, so don’t take any chances.

We’re always available with expert sewer backup cleaning services for Chicago, IL and the suburbs. Our teams are certified and fully equipped to handle any type of sewage leak cleanup.

If you have doubts about doing it yourself, call ServiceMaster Restoration by Zaba. Let us handle the dirty work: 773-647-1985

What causes sewage backups in basements?

Damaged sewer lines are the most common sources of sewage backups in basements. The pipes might be old or damaged by invasive tree roots. Heavy rains can flood municipal drainage systems and push sewage back into basements. Clogged drains inside a home are another source of basement sewage backups.

Is my landlord responsible for sewer backups?

The landlord is responsible for maintaining a rental property’s plumbing system. However, if the cause of a sewer backup originates within your unit, you can be held responsible. Check your lease for details that apply to your situation. If you have renter’s insurance, check for water damage coverage.

Can sewage backup make you sick?

Yes. Diseases caused by sewage contamination include E. coli, tetanus, cholera, typhoid fever, encephalitis and West Nile virus. Don’t risk your health. Always wear OSHA-rated personal protection gear when cleaning out a basement contaminated by sewage backup. It’s best to leave this type of work to certified restoration professionals.

How much does sewage backup cleanup cost?

The final cost of cleaning a sewer backup in your basement can vary widely, depending on the exact situation and the amount of damage you have suffered. Most jobs will range between as low as $2000 and as much as $10,000.
A word of advice – every cleanup situation is different. There is absolutely no way to give an accurate price quote over the phone or the Internet. Any true professional will tell you that they need to come out in person, inspect your property, and assess the damage before they can determine a remedy.
No, cleanup and restoration usually is not cheap, but the real question is, if sewage has backed up into your cellar, how can you afford to NOT do whatever it takes to correct that problem?

Does bleach kill sewage?

Most people who have suffered a sewage backup into their basement or another part of their home clean the mess up as best as possible and then try to sanitize everything with a generous application of store-bought bleach.
But did you know that there are over a dozen diseases linked to raw sewage or water contaminated by sewage? This includes e-coli, hepatitis A, and typhoid fever.
Even worse, some of these illnesses are caused by bacteria or parasites that are actually resistant to chlorine. In other words, disinfecting with bleach may not help protect you at all. 
With most of these illnesses, symptoms are uncomfortable but rarely serious – nausea, stomach cramps, abdominal pain, and diarrhea. But serious complications are also possible – high fever, infection, permanent weakness, coma, and death.

What should I do if I’m exposed to sewage?

Wash hands thoroughly with an antibacterial soap any time you take a break and always after a cleanup shift. Be sure to get under fingernails with a stiff brush.
Don’t risk transferring bacteria from your gloves to your face. Never touch your mouth, eyes, nose or ears while working. The contact can result in serious diseases including, encephalitis, viral gastroenteritis and salmonella.
Securely bag work gear, store it in a safe place, and take a shower at the end of each cleanup session. Don’t mix contaminated work clothes with regular clothing, even in the laundry.
Disinfect and cover any injury right away, and contact your doctor. Also, call his or her office if you begin feeling ill during cleanup. The doctor may recommend a visit to the nearest emergency clinic, as well as inoculations for diphtheria and tetanus.