When municipal sewer systems get backed-up, where does the water and sewage go?
Well, unfortunately, it can end up in your electronics-laden basement. It can rush back up into the home and could destroy anything it comes into contact with. Finished basement or not, the cleanup and repair after a sewer back up can be extremely expensive and time consuming.
The best way to minimize the potential for sewer backup in your basement is to install a sewer backwater valve.
This video will answer your questions and give you more info.