Bought a home, 14 years old built from an existing structure. I noticed in the basement where the water heater is a sump pit with liner and cap was covered over with vinyl flooring. I got curious and cut out the flooring to find stagnant water cob webs, no smell really. After shocking it with clorox I wet vacd it out and it's been dry ever since even through the most rain I've seen in Jersey in February. At the bottom of it were a hand full of 1 or 2 inch stone and building material. The Columbo in me thinks the water heater may have busted at some point and water got in that way. Any ideas on what the explanation is for a sump pit with no pump? Also what do I do with the pit now? Fill it in? Leave it alone? Is it right to just vinyl floor over it?