Sewage Backup Safety: Why Category 3 Water Is Hazardous

The three water categories

• Category 1: clean water from a supply line or sink
• Category 2: gray water with some contamination, such as washing machine or dishwasher discharge
• Category 3: grossly contaminated water, including sewage, toilet backflow and floodwater from outside

Clean water that sits can degrade to a higher category over time.

What makes sewage dangerous

Sewage can contain bacteria, viruses and parasites. Exposure through skin, eyes, mouth or airborne droplets can cause illness. Children, older adults and anyone with a weakened immune system face higher risk.

What to do right now

1. Stop using sinks, toilets, showers and appliances
2. Keep people and pets out of the area
3. Do not run the HVAC or fans that could spread contamination
4. Wear gloves, boots and a mask if you must enter
5. Call a professional cleanup provider and a plumber

What professionals do differently

Crews wear protective equipment, contain the work area, extract contaminated water, remove porous materials and apply antimicrobial cleaners to hard surfaces before drying. Read about sewage cleanup.

Fix the cause

A plumber should locate the blockage. If it is in the private lateral, it is generally the owner’s responsibility. If it is in the city main, notify public works. Consider sewer backup coverage on your policy.

See our insurance claims help page for guidance on documentation.

Quick answers

West Valley Water Damage is a referral service. Information here is general and not legal, insurance or engineering advice.