What Cat-3 Sewage Cleanup Protocol Actually Involves
Category-3 water under IICRC S500 is grossly contaminated water — sewage, river water, ground intrusion from agricultural runoff, certain flood water. The protocol is fundamentally different from clean-water restoration because the water itself is hazardous to occupants and to our crew.
Phase 1 — site control: isolating containment (zip walls + plastic) around the affected area, negative-air pressure with HEPA-filtered exhaust, full PPE for crew (Tyvek suits, P100 respirators, gloves, foot covers), occupants evacuated from the affected area for the duration of the cleanup phase. The site is treated as a contamination zone, not just a wet zone.
Phase 2 — removal: all porous materials below the documented flood line come out. Carpet, carpet pad, baseboards, drywall to 16-24 inches above contamination line, insulation, untreated wood, anything absorbent. Materials are bagged for disposal, not stockpiled in the building. We document everything removed for the insurance claim.
Phase 3 — decontamination: hard surfaces below the contamination line get HEPA vacuumed, washed with detergent, rinsed, then treated with EPA-registered antimicrobial. Drying equipment runs concurrently to bring the structure back to dry standard.
Phase 4 — verification: air quality testing confirms the space is safe for re-occupancy before reconstruction begins. Done correctly, the affected space is clearable in 5-7 days for the cleanup phase, then reconstruction follows.