Sewage cleanup after a backup or overflow

What to do in the first hour

• Stop adding water. Do not flush toilets, run showers, the dishwasher or the washing machine; every drop drains toward the blockage and comes back up at the lowest fixture.
• Keep people and pets out of the area. Close the doors to the affected rooms and keep children away from the water.
• Stay clear of electricity. If water is near outlets, cords or a water heater, switch off the circuit at the panel only if you can reach it without standing in water.
• Protect your hands and feet if you must go in. Ready.gov's flood guidance says to wear heavy work gloves, protective clothing and boots during cleanup.
• Photograph everything before anything is moved, and tell your insurer about the loss.

Why sewage is handled differently from a clean leak

The IICRC's S500 standard sorts water damage into three categories, and sewage belongs to the most contaminated one, together with rising floodwater from rivers and streams. That category changes what can be kept. After a clean supply-line leak, carpet, pad and drywall can often be dried in place. After a sewage backup, absorbent materials that the water touched are generally removed and discarded: carpet and pad, the lower part of drywall, insulation, upholstered furniture and particleboard cabinets. Hard, non-porous surfaces such as tile, sealed concrete and metal can usually be cleaned and kept. The EPA's flood cleanup guidance points the same way: clean and dry the house and everything in it within 24 to 48 hours if you can, because things that stay wet for more than two days usually grow mold.

Clean water does not stay clean. A toilet supply line leak that sits for a few days in a warm room, soaking into carpet, can turn into a more contaminated category than it started as. If you are unsure which category you have, our article on water damage categories explains the differences.

How the cleanup is done

1. Set up the work area. Close it off from the rest of the house with plastic sheeting, cover the walkway out, and set up air filtration.
2. Remove the water and solids. Extract the liquid and remove solid waste and debris.
3. Take out porous materials. Cut drywall above the water line, remove carpet, pad, insulation and baseboards, and bag them for disposal.
4. Clean every surface left. Wash the floor, the lower walls and the framing with detergent solutions, rinse, and apply an antimicrobial where the protocol calls for it.
5. Dry. Air movers and dehumidifiers run until the framing and subfloor read dry.
6. Rebuild. New drywall, insulation, flooring and trim, as on any reconstruction after damage job.

Finding and fixing the cause

Cleanup does not fix the line, and a backup that is cleaned without a repair tends to return. The cause is usually one of a few things: a blockage in the building's drain line, roots or a collapsed section in the sewer lateral that runs from the house to the street, grease built up in a kitchen line, or, during heavy storms, a public main that is overloaded. A plumber with a camera can usually show which one. The repair is the plumber's work, and we coordinate the order so the line is fixed before the floors and walls go back.

Who owns the line matters. In many Bay Area cities and utility districts, the property owner is responsible for the sewer lateral from the house to the connection at the main, and some districts, such as East Bay Municipal Utility District, require a compliance certificate for the lateral when a house is sold or when permitted work passes a set value. Around Dallas–Fort Worth, cities draw the line between the owner's service line and the city's main in their own way. Your city's wastewater or public works department can tell you where the boundary sits at your address.

Backups and insurance

Coverage for sewer and drain backups varies more than most homeowners expect. Many policies leave out water that backs up through drains unless an endorsement for it has been added, and flood water is a separate policy again. Read the water section of your policy, or ask your agent, before you assume either way. Whatever the policy says, the claim goes better with clear records: photographs before anything is removed, a list of the items thrown out, and the plumber's report on the cause. Our insurance claim documentation page lists what we document on a job like this.

Basements, crawl spaces and slab homes

The lowest fixture in the house is where sewage appears first. In Bay Area homes with a raised foundation, that can be a shower or toilet in a lower bathroom, and the water may also run into the crawl space below, where it soaks insulation and the soil under the house. Crawl space cleanup means removing saturated insulation and debris, cleaning the framing that was splashed, and drying the area before new insulation goes in. In Dallas–Fort Worth, most homes sit on a concrete slab, so a backup spreads across the floor at once; the slab itself can usually be cleaned, but anything glued down to it, such as carpet, pad or laminate, generally comes up.

Sources: IICRC, S500 Standard for Professional Water Damage Restoration; U.S. EPA, Flood Cleanup to Protect Indoor Air Quality; Ready.gov, Floods; East Bay Municipal Utility District, Private Sewer Lateral program; Texas Department of Insurance, Home insurance guide.