Published by All Dry Services of the Bluegrass
Water losses are graded by contamination, not by volume. A clean supply line is category 1. Water with some contamination, from an appliance or a washing machine, is category 2. Sewage is category 3, and the difference is not a matter of degree.
What category 3 means in practice
Grossly contaminated water, carrying bacteria, viruses and other pathogens. Not something to be in contact with, and not something to be in the room with for long without protection. Everything that follows comes from that one fact.
Before anyone arrives
Keep people and pets out. Close the door. This is the whole of the useful advice for most households.
Stop using water upstream. Every flush and every drained sink adds to what is already backing up.
Do not run the HVAC. If it moves air through the affected space it aerosolises contamination into rooms that were fine.
Do not attempt to clean it. A mop redistributes it. A household vacuum aerosolises it. Neither disinfects anything, and both put you in contact with it.
What can be cleaned and kept, and what has to come out
Non-porous and semi-porous material such as concrete, tile, sealed hardwood, framing and subfloor can be cleaned, disinfected and kept. Nothing comes out that can be verified as decontaminated where it stands.
Porous material in the affected area is removed rather than cleaned: carpet and pad, drywall to a defined height above the water line, insulation, particleboard, and most upholstery. Not because they cannot be made to look clean, but because they cannot be verified as decontaminated all the way through. That distinction is what the scope of work is built on, and it is why the removal often extends past the visible edge of the water.
The sequence
Assessment and containment first, so the work does not contaminate the rest of the building. Then extraction and disposal of the water and the affected porous material, then disinfection and sanitation of every surface that stays, then drying and dehumidification to a measured target, then rebuild and repair of what had to come out. HEPA air filtration runs through all of it. Skipping straight to drying is how a house ends up dry and still contaminated.
Rural properties and septic
A good deal of our service area is on septic rather than municipal sewer, and a septic failure behaves differently from a city sewer backup. It tends to surface in the yard or come up through the lowest drain, and the underlying fault is a septic issue that a restoration company does not fix. We handle the contamination inside the building; the system itself needs a septic contractor, and doing one without the other means doing it again.
Insurance
Sewer and drain backup is commonly excluded from standard homeowner policies unless a specific backup endorsement was added. It is an inexpensive endorsement and a lot of people do not know whether they have it. Worth checking before you need it rather than after.