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First 48 hours

Sewage backup: what to do in the first 48 hours

By Vincent WallaceUpdated Expert review pending

What to do right now

Stop using sinks, showers and toilets right away (Red Cross), keep children and pets out, and do not touch the water. Sewage is Category 3 water under the IICRC S500 standard: grossly contaminated and able to carry bacteria, viruses and parasites (EPA). Call your sewer utility or a plumber to find the blockage, photograph the damage, and call your insurer to ask whether your policy includes water-backup coverage. Most sewage cleanup is a job for a professional.

On this page
  1. First hour: stop the flow and keep people out
  2. First 24 hours: find the cause and call for help
  3. 24 to 48 hours: clean up or hand it off
  4. After 48 hours: what comes next

First hour: stop the flow and keep people out

  1. Stop using water. Red Cross says avoid sinks, showers and toilets if you suspect sewage lines are damaged. Turn off the washer and dishwasher too.
  2. Keep children, pets and anyone with a weak immune system out of the area.
  3. Do not touch the water. Sewage is Category 3 water, which the IICRC S500 standard defines as grossly contaminated. EPA says raw sewage carries bacteria, viruses and parasites.
  4. Turn off power to the area only if you can reach the breaker from a dry spot. Otherwise call an electrician (CDC).
  5. Open windows if you can do it without walking through sewage.

First 24 hours: find the cause and call for help

  1. If you are on city or county sewer, call your sewer utility. It can check whether the public main is blocked.
  2. If the main is clear, call a licensed plumber. Homeowners are usually responsible for their own sewer line. In Pinellas County, for example, owners maintain the line from the house to the property line.
  3. If you have a septic system and the yard is flooded, do not use the system until water in the drain field drops below the water around the house (EPA).
  4. Take photos and video of the damage, including the water line on walls. NAIC says document damage before cleanup.
  5. Call your insurer. Ask whether your policy has a water-backup endorsement.

24 to 48 hours: clean up or hand it off

  1. If you go in, wear rubber boots, rubber gloves and goggles (CDC). Cover any cuts.
  2. EPA says rugs, curtains, flooring, wallboard and upholstered furniture that touch sewage usually must be replaced. Photograph them, then bag them.
  3. Wash and disinfect hard surfaces. EPA says flooded basements must be thoroughly cleaned and disinfected.
  4. Wash your hands with soap and water when you finish. Wash cleanup clothes in hot water, apart from other laundry (CDC).
  5. For anything beyond a small spot on a hard floor, call a sewage cleanup professional. Read DIY sewage cleanup to see where the line is.

After 48 hours: what comes next

Our guide to a sewage backup in the basement covers drying, disinfection and prevention. Check sewage cleanup costs before you sign, and read is sewer backup covered by homeowners insurance before your adjuster visit. Use our questions to ask a restoration company when you call around. More help is on the sewage hub.

When to call a pro

  • Sewage covers more than a small spot on a hard floor.
  • Sewage soaked carpet, drywall, insulation or furniture.
  • The backup keeps happening or more than one drain is backing up.
  • Sewage is near outlets, the electrical panel, the furnace or the water heater.
  • Children, or anyone with asthma, COPD or a weakened immune system, lives in the home (groups CDC flags as higher risk).
  • You have a septic system and the drain field is flooded.

Questions to ask before you hire anyone

Common mistakes

  • Running the washer, dishwasher or shower while the line is blocked.
  • Cleaning before taking photos for the insurer.
  • Trying to save soaked carpet, drywall or upholstered furniture. EPA says these usually must be replaced.
  • Pouring chemical drain cleaner into a backed-up main line.
  • Assuming homeowners insurance covers it. Ask your insurer about water-backup coverage before you sign with a cleanup company.

Sewage backup: first 48 hours

Questions people ask

Is sewage backup dangerous?

It can be. EPA says raw sewage carries bacteria, viruses and parasites that can cause illness from mild stomach upset to serious disease. Restoration pros treat it as Category 3 water, the most contaminated class under the IICRC S500 standard. Avoid contact, keep vulnerable people away, and wash with soap and water after any exposure.

Who do I call for a sewage backup?

Call your sewer utility first if you are on city or county sewer; it can check whether the public main is blocked. If the main is clear, call a licensed plumber, since homeowners usually own the line from the house to the property line. Then call your insurer and a sewage cleanup professional.

Does homeowners insurance cover sewage backup?

It depends on your policy. Sewage backup is often handled through a separate water-backup or sewer-backup endorsement, which may carry its own limit. Check your declarations page and ask your insurer before work starts. Our sewer backup coverage guide explains how the endorsement works.

Sources

  1. Sanitary Sewer Overflow (SSO) Frequent Questions, U.S. Environmental Protection Agency (April 13, 2026)
  2. Category of Water Damage and Weather-Related Events (position statement, citing ANSI/IICRC S500), Institute of Inspection, Cleaning and Restoration Certification (March 16, 2026)
  3. Checking Your Home's Utilities, American Red Cross (accessed 2026-10-19)
  4. Guidelines for Cleaning Safely After a Disaster, Centers for Disease Control and Prevention (August 26, 2026)
  5. Frequent Questions About Flooded Homes (septic systems), U.S. Environmental Protection Agency (August 28, 2026)
  6. Private Sewer Lateral Program Frequently Asked Questions, Pinellas County Utilities (March 8, 2024)
  7. Navigating the Claims Process: Recover and Rebuild, National Association of Insurance Commissioners (June 23, 2021)

Safety note. This page follows CDC, Ready.gov, FEMA and American Red Cross guidance; it cannot see your home. Return home only when authorities say it is safe. When in doubt, wait for a professional.

How this page was made. Drafted with AI assistance from the public agency, statute and industry sources listed above, then edited and published by Vincent Wallace. An independent expert has not yet reviewed this page; when one does, their name and the review date will appear at the top. See our editorial policy. Spotted an error? Tell us.