Sewage Backup in the Basement: Health Risks and Cleanup Steps

The short version

If sewage backs up into your home: keep everyone, especially children and pets, out of the area; stop using water and flushing toilets; turn off power to the area if you can do it safely; photograph the damage; and get the area professionally cleaned and disinfected. Porous materials that touched sewage, such as carpet, pad, drywall and insulation, are removed, not cleaned.

Why sewage is different from other water damage

Sewage is classified as Category 3, or black water, under the IICRC S500 standard. It can carry bacteria, viruses and parasites that cause illness. Unlike a clean-water leak, it cannot simply be dried; everything it touched has to be cleaned and disinfected, and anything porous has to be removed.

Common causes

• Heavy rain overloading the sewer system, pushing water up through basement floor drains
• A blocked sewer lateral, the line from your house to the street, from tree roots, grease or debris
• A collapsed or damaged sewer line in older homes
• Flushing wipes, grease or other items that clog the line
• Floodwater pushing sewage back through drains during a river or creek flood

In Charleston, the public sewer system is run by the Charleston Sanitary Board. If several homes on your street back up at once, or you suspect a problem in the main line, contact them. A problem in your own lateral is usually the homeowner’s responsibility.

What to do right away

1. Keep people and pets away from the affected area.
2. Stop running water anywhere in the house: no flushing, showers, dishwasher or laundry. Water you send down the drain may come back up.
3. Turn off power to the basement if water is near outlets or appliances and you can reach the breaker safely.
4. Do not use household fans to dry the area, which can spread contamination.
5. Photograph everything for your insurer.
6. Call a plumber to clear the line, and get the cleanup handled by a provider with the right protective equipment.

What has to be thrown out

Photograph each item before it is thrown out, with model and serial numbers where possible.

How sewage cleanup works

The area is contained, standing sewage is extracted, porous materials are removed, and every remaining surface is cleaned with detergent and treated with a disinfectant. The structure is then dried with dehumidifiers and air movers until moisture readings are normal. Air scrubbers may be used to clean the air. Flooded basement cleanup and emergency water removal cover the extraction and drying side, and mold after flooding explains why drying matters for preventing mold.

Insurance for sewage backups

Many standard homeowners policies exclude sewer and drain backups unless you have a water backup endorsement. If the backup was caused by flooding, coverage depends on flood insurance. Check your policy and call your insurer early. See water damage insurance in West Virginia.

How to prevent sewage backups

• Install a backwater valve on the main sewer line, which lets sewage flow out but not back in.
• Do not flush wipes, even ones labeled flushable, and keep grease out of drains.
• Have the lateral inspected with a camera if you have slow drains, gurgling or past backups, especially in older homes with large trees nearby.
• Plug or cap unused floor drains in the basement.
• Add a water backup endorsement to your insurance.

Where backups happen most

Older homes with aging sewer laterals, like many in North Charleston, the West Side and the East End, and homes in low areas that flood, such as parts of Kanawha City, see the most backup calls. If you are preparing for high water, see how to prepare your home for flooding. For help with any type of damage, see local restoration providers in Charleston.

Sewage backup FAQs