A backwater valve installs on the sewer lateral and closes automatically when flow reverses, which stops a surcharged municipal main from relieving into your basement floor drain. For a Wichita house that has flooded this way, it is the fix that actually addresses the cause.
It is a permitted installation and it requires excavation to reach the lateral, plus an access cover so the valve can be inspected and cleared. That access is not optional, because a valve nobody can reach is a future blockage.
The valve does not help with a blockage in your own lateral, which is a different problem with a different solution. The camera tells you which you have.
Technician insight
The valve needs annual inspection through its access cover. Debris caught on the flap holds it open, which defeats the entire installation.