A basement sewer backup in a century-old bungalow

The situation

Illustrative example. Not a real job or customer.

A hypothetical bungalow built around 1910 has a finished basement with carpet, a guest bedroom and a laundry area. The sewer line from the house to the street is original clay pipe, and a large street tree stands nearby. One evening after laundry and dishes run back-to-back, gray-brown water rises out of the basement floor drain and spreads across the laundry room and into the carpeted family room.

1. The owners stop all water use in the house, keep their children upstairs, and avoid walking through the water.
2. They call a plumber, who runs a cable through the cleanout and clears a root blockage, then recommends a camera inspection.
3. The camera shows roots entering at several joints and a section of pipe with an offset. The plumber explains repair options, from lining to excavation, and that a permit may be required.
4. The owners call their insurer and learn that their policy includes a water backup endorsement with a separate limit.
5. A restoration firm removes the carpet, pad and lower drywall that the sewage touched, cleans and disinfects the slab and framing, and dries the space.
6. The owners contact Denver's wastewater services to ask where homeowner responsibility for the sewer line ends and the city's begins.

The basement is cleaned and dried, and porous materials that contacted sewage are replaced. The owners schedule a sewer line repair and decide to install a backwater valve if the plumber confirms it suits their layout. They change the finished basement's flooring to a material that tolerates water better.