... you know, that pump that sits at the bottom of a pit in the basement of houses that periodically kicks in to pump out water that has seeped in through the foundation? I ask because I suspect that we were flooded a few years back when the storm drains overloaded and water flowed back into the pit from the sewer. I am not sure this is what happened as water also came in through the light shafts (which have since been walled off). So, I was thinking about shelling out to have a one-way valve installed in the output pipe to prevent this happening, then thought... do sump pumps already have this feature by default? Anyway, in case anyone knows anything about this it would be appreciated.
I had a friend who lived at the bottom of a hill and used a sump pump to move all the sewage up to the sewage system.
The sump pump had a one-way valve to prevent backflow, however he had an extremely heavy-duty one-way valve added above the sump pump to make sure.
Having the one-way valve fail would be extremely unpleasant, having a second extremely reliable one reduces the odds of a catastrophic backflow greatly.