Our Central air is plugged into the drain under the concrete slab. We've been in a no rain for months, but hot. During that time our sump pump broke. The whole area under the concrete floor (40x45) filled up with this water from the air cond. I put in a new sump pump. Now the basement smells. Some days its worse. I put bleach in the pit. It stopped the odor for awhile. Now its back. I got some die from a plumber and ran it in the sewer line. No leaks. He has a camera to check sewer pipes. No cracks. Line is clean and running as it should. Our sump pump is open. I was reading about it and it says it should be vented, but it never was. The pit is concrete. If I have to vent it; do I have to tear up the floor, or is there something to retro fit.