I'm bumping this thread to confirm what others have said. I live in the city on a small lake in the lowest part of my neighborhood. I called my local utility office and spoke with the supervisor of the sewer dept. and he confirmed that based on my location it would be very prudent to get a backflow preventer on my sewer line. Nice guy who understood that I was worried about a SHTF scenerio and admitted that it could be problem for me rather quickly if power was knocked out to the city sewer pumps.
Going to get to work on that in a few weeks.
Going to get to work on that in a few weeks.