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Water DamageSewage Backup Cleanup Cost Calculator
Sewage backup is Category 3 “black water” — a biohazard that demands full sanitizing and removal of anything porous it touched. Enter the affected area for an estimate.
Sewage backup cleanup runs about $7–$12+ per square foot of Category 3 black water, so a 300 sq ft job lands near $4,400 including sanitizing equipment. Whole-basement or prolonged backups commonly exceed $10,000 once flooring, drywall, and contents are replaced.
How this calculator works
We use a high Category 3 per-square-foot rate to reflect biohazard handling, then add sanitizing and equipment. Black water means almost all porous materials it contacted — drywall, carpet, insulation — are removed and replaced rather than dried, which is why sewage is the most expensive water category.
What changes the number
- Category 3 black water requires antimicrobial sanitizing and protective equipment.
- Porous materials that touched sewage are removed, not salvaged.
- Source matters — a mainline backup affecting the whole basement costs far more than a single fixture.
- Health risk means occupants often relocate during the work.
Frequently asked questions
Why is sewage cleanup so expensive?
It’s a biohazard. Crews need protective equipment, antimicrobial treatment, and must remove (not just dry) most porous materials it contacted — all of which costs more than clean-water cleanup.
Is sewage backup covered by insurance?
Only if you carry a sewer/water backup endorsement — it’s usually not in a standard policy. Check your coverage, then weigh filing with our water damage insurance claim calculator.