Sewage Backup Cleanup: Health Risks, Insurance and Next Steps

A sewage backup is not ordinary water damage. Raw sewage can carry germs that cause stomach illness and infections, so keep everyone out of the area, stop using water in the house, and call a professional for anything beyond a very small spill.

Insurance is the second surprise for many people: a standard homeowners policy usually does not cover sewer backup unless you bought a water backup endorsement (Triple-I ↗).

Why sewage backup is dangerous

Floodwater and sewage can contain human waste and other germs. The CDC says contact can lead to wound infections, skin rashes, stomach illness and tetanus, and that eating or drinking anything contaminated can cause diarrheal disease such as E. coli or Salmonella infection (CDC ↗).

For people who handle sewage, the CDC advises seeking medical care promptly for symptoms like vomiting, stomach cramps and watery diarrhea (CDC ↗).

The EPA notes that sewer overflows can back up into homes, causing property damage and threatening public health (EPA ↗).

What "Category 3" water means

Restoration companies sort water damage into categories under the ANSI/IICRC S500 water damage standard, currently the 5th edition from 2021 (IICRC ↗). The S500 defines Category 3 water as "grossly contaminated" water that "can contain pathogenic, toxigenic, or other harmful agents and can cause significant adverse reactions to humans if contacted or consumed." Its examples include sewage and wasteline backflows that originate from beyond any trap regardless of visible content or color (IICRC ↗).

In plain English: water that came back up out of a floor drain, toilet or tub from the sewer line is treated as Category 3, even if it looks fairly clear.

That matters for cleanup. The S500 says that for Category 2 or 3 water, contamination should be cleaned up (remediated) before drying begins, and that restorers must use contamination controls and worker protection (IICRC ↗).

What to do right now

1. Keep people and pets out. The CDC advises keeping children and pets away until cleanup is finished (CDC ↗).
2. Stop running water. Don't flush toilets, run the washer or dishwasher, or shower. That water has to go somewhere, and if the line is blocked it can come back up into the basement.
3. Make electricity safe. If circuits or equipment got wet, the CDC says to turn off power at the main breaker, but to call an electrician if you'd have to stand in water to reach it (CDC ↗).
4. Leave if you smell gas. Get out and call emergency authorities (CDC ↗).
5. Call for help. Contact a plumber or your local sewer utility to find out whether the blockage is in your line or the public sewer, and call your insurer.
6. Document everything. Take photos and video before cleanup, list damaged property, and keep damaged items until the adjuster sees them if you safely can (TDI ↗). Triple-I also suggests saving all cleaning and repair receipts and contacting your insurance professional as soon as possible (Triple-I ↗).

What not to DIY

The EPA says that if water damage was caused by sewage or other contaminated water, you should call in a professional with experience cleaning and fixing buildings damaged by contaminated water (EPA ↗).

Avoid these common mistakes:

• Don't wade in without protection. The CDC recommends rubber boots, rubber gloves and goggles if sewage is involved (CDC ↗). Cover any cuts with a waterproof bandage (CDC ↗).
• Don't try to save soaked porous materials. The CDC says to remove and discard drywall and insulation contaminated by sewage or floodwater, and to throw away items you can't clean and dry quickly, like mattresses, carpet, upholstered furniture and stuffed animals (CDC ↗).
• Don't just dry it and call it done. Under the S500, contaminated water should be cleaned up before drying, not dried in place (IICRC ↗).
• Don't run the HVAC if you suspect it's contaminated with mold (EPA ↗).
• Don't wait. The EPA says water-damaged areas should be dried within 24 to 48 hours to prevent mold (EPA ↗).

If you do handle a very small backup yourself, such as a toilet overflow onto a hard floor, wear the CDC-recommended gear, wash your hands with soap and water right after, avoid touching your face, and wash your work clothes in hot water with detergent (CDC ↗; CDC ↗).

Anyone with health concerns should talk to a health professional before starting cleanup (EPA ↗).

Is sewage backup covered by insurance?

Usually not by a standard policy alone.

• Standard homeowners and renters policies. Triple-I says sewer backup is not covered under standard homeowners or renters insurance, nor by flood insurance (Triple-I ↗).
• Water backup endorsement. Triple-I says coverage can be bought as a separate product or as an endorsement to a homeowners policy (Triple-I ↗), and that it is available from most providers for a nominal cost (Triple-I ↗).
• What the endorsement covers. Florida's Department of Financial Services describes it as covering water that backs up into the home from a sewer, sump or drain, and says it does not cover damage caused by floods (Florida DFS ↗).

Check your declarations page for a "water backup" or "sewer and drain backup" endorsement and its dollar limit. Endorsement names, limits and rules vary by insurer and state. If you can't tell what your policy covers, ask your agent in writing. For disputes, your state insurance department or an attorney can help, and this guide on denied insurance claims ↗ explains your options.

How to prevent sewer backups

Triple-I explains that sewer lines can be blocked by tree roots growing into cracks and joints, and that systems carrying both storm water and sewage can be overwhelmed in heavy rain (Triple-I ↗). The EPA lists blockages, line breaks, power failures and defects that let storm water and groundwater overload the system as causes of sewer overflows (EPA ↗).

Steps you can take:

• Install a backwater valve. Triple-I says a properly installed and maintained backwater valve lets sewage go out but not come back in (Triple-I ↗). A licensed plumber can tell you whether your home needs one.
• Keep grease out of drains. Pour cooking oil into a heat-resistant container instead of down the sink (Triple-I ↗).
• Don't connect other drains to the sewer. Triple-I warns that connecting French drains, sump pumps and other flood control systems to the sanitary sewer is illegal and can clog your line (Triple-I ↗).
• Take "before" photos of your basement and keep a home inventory, so a future claim is easier (Triple-I ↗).

Choosing a cleanup company

Look for a company with experience in contaminated water, as the EPA recommends. Ask whether it follows the IICRC S500 standard and how it will contain the area and protect workers.

The FTC warns that scammers appear after disasters. It advises confirming a contractor's license and insurance, getting a written contract, avoiding cash or wire payments, and never signing your insurance check over to a contractor (FTC ↗). Licensing rules differ by state; see Texas, Florida and New York, plus our guides on choosing a restoration company and restoration contractor scams.

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Frequently asked questions

Is sewage backup dangerous to breathe or touch?

Contact is a real health risk. The CDC links contact with sewage-contaminated water to wound infections, rashes and stomach illness (CDC ↗). Keep children and pets away.

What is Category 3 water?

Under the IICRC S500 standard, it is grossly contaminated water that can contain harmful agents, including sewage and backflows from beyond a drain trap (IICRC ↗).

Can I clean up a sewage backup myself?

The EPA recommends a professional experienced with contaminated water (EPA ↗). A very small spill on a hard surface may be manageable with rubber boots, gloves and goggles.

Is sewer backup covered by homeowners insurance?

Usually not, unless you added a water backup endorsement. Triple-I says it isn't covered by standard homeowners or flood policies (Triple-I ↗).

Can I save carpet after a sewage backup?

Usually not. The CDC says to throw away carpet and other items you can't clean and dry quickly, and to discard drywall and insulation contaminated by sewage (CDC ↗).

How do I stop sewage from backing up again?

Ask a plumber about a backwater valve, keep grease out of drains, and don't connect sump pumps or French drains to the sewer line (Triple-I ↗).