Went on vacation for two weeks, had 24" of rain in one/two days, came home to a partially dried out, previously-flooded basement.
Not sure where the water came in. Currently removing plywood and drywall and insulation to get rid of mold, and to investigate cause.
One possibility I am considering is that I had a backup from the sewer line and it came up from the floor drain in the basement laundry room. If that turns out to be the case, I'd like to have a backflow preventer installed. Note: We have a combined stormwater and sewer system where I live. I do not live at the bottom of a hill. In fact, I'm pretty much at the top of the hill in my area.
The linked image shows the main trap rough in when the basement was finished. The large vertical pipe to the right is the trap vent, and it exits a few inches above the ground level on the front of the house.
The sewer pipe is 9-10 feet below the surface of the ground surrounding the house, so I don't believe it's feasible to install it outside. Thus, I think I need to install it in the basement.
Can I install the backflow preventer immediately after the main trap vent? That is, to the right of the main trap vent?