I recently had the misfortune of a flooded basement due to a failed sump pump. While putting in the new pump, I noticed that there was a substantial amount of water coming into the sump pit FROM the sump discharge pipe, i.e. the place where water should be going OUT. In fact, were it not for the check valve in place it would've been near impossible to put in the new pump due to the amount of water coming in. I'm guessing this isn't normal by any means and why the old pump kept running every few minutes and eventually died (although it did last for 7 years.) What could be causing this constant backflow?