Sewage Backup: Who to Call First (It's Not a Plumber)

Frequently Asked Questions

Who do I call for a sewage backup?

Call an IICRC-certified water damage restoration company that handles Category 3 (biohazard) work -- not a plumber, not a general cleaning service. Sewage backup is classified as black water under IICRC S500 standards and contains pathogens including E. coli, hepatitis A, norovirus, and other harmful organisms. It requires full PPE (respirators, Tyvek suits), EPA-registered hospital-grade disinfectants, HEPA air scrubbing, and regulated disposal of all affected porous materials. A plumber can clear the blockage -- but they cannot safely remediate the contamination.

Is sewage backup covered by homeowners insurance?

No -- not under a standard HO-3 policy. Sewage and drain backup is a specifically excluded peril under most standard policies. Coverage requires a Water Backup and Sump Overflow endorsement, which costs $50--200 per year and is added to your standard policy. If you have this rider, sewage backup is covered up to your endorsement limit (typically $5,000--25,000). If you do not have the rider, you pay out of pocket. Check your policy declarations page right now -- and if you do not have the endorsement, add it at your next renewal.

What should I do immediately when sewage backs up?

Do these in order: (1) Leave the affected area immediately -- do not wade through sewage water without full protective gear. (2) Do not flush any toilets or run any water -- every drain in the house connects to the same line. (3) Do not run HVAC -- it spreads contaminated air through ducts. (4) Call an IICRC-certified Category 3 restoration company immediately. (5) Call a licensed plumber to identify and clear the blockage source. (6) Photograph everything from outside the affected area before remediation begins.

What causes sewage to back up into the basement?

The four most common causes: (1) Main sewer line blockage -- tree roots, grease buildup, or collapsed pipe in your private lateral; (2) Municipal sewer overflow -- heavy rain overwhelms the city system and backs up through floor drains; (3) Grease and debris blockage -- restaurant-style grease accumulation in drain lines; (4) Pipe collapse or offset in older clay or cast-iron lines. A plumber with a camera scope can identify the exact cause -- this is important for insurance purposes (municipal overflow may have a separate liability claim against the city).

How much does sewage backup cleanup cost?

Sewage backup cleanup costs $3,500--$50,000 depending on affected area. One bathroom backup averages $3,500--$8,000. Full basement sewage flooding averages $15,000--$50,000. Costs are higher than clean-water events because: (1) all porous materials in the contamination zone must be removed and disposed of as biohazardous waste, (2) EPA-registered disinfectants require multiple applications and dwell times, (3) HEPA air scrubbing must run continuously, and (4) post-remediation clearance testing is required before re-occupancy.