What Should I Do If I Smell Sewage in My Basement?

Last updated October 25, 2026

The short answer

First Steps

Get everyone out of the basement and open any windows to let in fresh air. Sewage odors can contain gases that are unpleasant and may be unhealthy to breathe. If you feel unwell, see a doctor. Do not run fans or the HVAC system, as that can spread the smell through the house.

Find your main water shutoff valve and turn it off if you can do so safely. This can stop the flow if the smell comes from a backed-up drain. Write down the valve location now so you remember it later.

Look for the Source

Check for visible water, damp spots, or stains on the floor and walls. Look near floor drains, toilets, or washing machine connections. A sewage smell often comes from a backup in the main drain line or a crack in a pipe. If you have a sump pump, check whether it is working properly.

Do not touch or clean up any sewage yourself. It can contain harmful bacteria. Your job is to spot the source and then call for help.

Check floor drains for standing water
Look for damp spots on walls or floor
Inspect around the toilet base
Smell near washing machine hoses
Note any gurgling sounds from drains

Call the Pros

Contact local water damage pros who handle sewage backup cleanup and sanitation. They have the equipment to safely remove waste and disinfect the area. They can also identify the cause, like a blocked sewer line or a damaged pipe.

When you call, describe what you see and smell. This helps them prepare for the job. The pros will handle the cleanup and make the basement safe again. Ask about the likely cause and any steps you can take to prevent a repeat.

Avoid Health Risks

Sewage contains bacteria, viruses, and parasites that can make you sick. Keep children and pets away from the area. Do not use fans that blow air from the basement into the rest of the house.

Wear rubber boots and gloves if you must walk through the area, but avoid touching anything. Wash your hands thoroughly after any contact. If you have breathing problems or a weakened immune system, stay out entirely.

Prevent Future Odors

After the pros finish the cleanup, ask them about the cause. It might be a tree root in the sewer line, a broken pipe, or a clogged vent. Fixing the root problem reduces the chance of it happening again. Regular checks can help you catch small issues early.

Regularly check your basement for signs of moisture, especially after heavy rains. If you live in Detroit, keep your shutoff valve location written down. A little maintenance can save you from a bigger headache later. Also, consider scheduling periodic sewer line inspections with a plumber or a water damage professional.

Install a backwater valve to prevent backups
Avoid pouring grease or wipes down drains
Have sewer lines inspected periodically
Keep floor drains clear of debris
Check sump pump operation if you have one

Water damage does not wait

Water keeps spreading into floors and walls, so it is worth acting early. Calls are answered 24/7.

Call Now (313) 766-2970

Frequently asked questions

Is it safe to stay in the basement?

No, it is not safe to stay for long. Sewage fumes can contain methane and hydrogen sulfide, which are harmful to breathe. Open windows, leave the area, and call the pros. If you feel dizzy or sick, get fresh air and see a doctor.

Can I clean it up myself?

You can do simple surface cleaning, but a sewage backup requires professional sanitation. The pros have industrial disinfectants and equipment to safely remove waste and dry the area. Trying to do it yourself can expose you to health risks and may not fully clean the space.

Will my insurance cover the damage?

Policies vary, and your insurer decides what is covered. Check your policy for sewage backup coverage, which is sometimes an add-on. Take photos of the damage and keep receipts. Contact your insurance company to ask about your specific situation.