Sewage backup in your basement or crawlspace: what to do first

Treat any sewage backup as contaminated water. Keep people and pets out of the area, stop using sinks, toilets and appliances that drain, and don't try to clean it up with household supplies. Call a plumber or your sewer utility to deal with the blockage, and a restoration company to remove the sewage and clean and dry the space safely.

Why sewage is different from a clean water leak

Water from a broken supply line starts out clean. Sewage does not. It can carry bacteria, viruses and other things that make people sick, and it soaks into anything porous it touches. That is why the restoration industry treats it as the most serious kind of water damage.

It also changes what can be saved. Hard surfaces can usually be cleaned and disinfected. Carpet, pad, drywall, insulation and other porous materials that soaked up sewage usually need to come out.

What to do first

1. Keep everyone away from it, especially young children, anyone pregnant or older, anyone with a weakened immune system, and pets.
2. Stop using water. Every flush, shower or load of laundry can send more water to the backup.
3. Stay clear of electricity. Don't walk through water near outlets, cords or appliances. Only shut off power at the panel if you can reach it without stepping in water.
4. Don't touch it without protection. If you must walk through the area, wear rubber boots and waterproof gloves, and wash your hands well afterward.
5. Take photos and video of the water, where it came from and what it reached. It helps with any insurance claim.
6. Ask before running the furnace if the furnace, ductwork or air returns are in the affected area.

Find the cause

A backup usually comes from a clog or break in your own sewer line, or from a problem in the public sewer main. A few clues help:

• If only one drain backs up, the clog may be in that fixture's line.
• If the lowest drain in the house, often a basement floor drain or a downstairs toilet or tub, is backing up, the problem is more likely in the main line out of the house.
• If neighbors are having the same problem, contact your city or sewer district.

A licensed plumber can find and clear the blockage. Cleanup should wait until the line is working again, or the backup can return.

What professional cleanup involves

A sewage cleanup is more than pumping out water. It usually includes:

• Removing the sewage and standing water
• Removing contaminated porous materials such as carpet, pad, the wet section of drywall and soaked insulation
• Cleaning and disinfecting the hard surfaces that remain
• Drying the structure and checking it with moisture meters before anything is rebuilt

Crawlspaces need the same care. Soaked insulation and a contaminated vapor barrier are usually removed and replaced once the area is clean and dry. Moisture left behind can lead to mold, so drying matters as much as cleaning. The EPA's flood cleanup guidance covers the same basics for contaminated water.

Before any work starts, ask what will be removed, what can be cleaned in place, and what the recommended scope will cost.

Will insurance cover a sewage backup?

Sometimes. Many homeowners policies need a specific sewer or drain backup add-on, and coverage depends on your policy. Your insurer decides what is covered. Our guide on whether homeowners insurance covers water damage explains what to ask. Superior can help document the damage and coordinate with your insurance provider.

When to call Superior

Call us any time, day or night, if sewage has backed up into your home. We serve the Portland metro and Vancouver and Clark County, and we usually arrive within 45 minutes. Call to confirm the arrival time for your address. You can learn more about our water damage restoration and mold removal work, read whether it is safe to stay in a house with water damage, or request a callback if it is not urgent.