Hi, I have a large drain pit in my garage floor. It is similar to those you would find at a service station or car dealership. The portion of the pit that should hold water is about 14-1/2" wide and 22-1/2" deep. There is a 4" cast iron drainpipe that goes down the pit about 14-1/2". The problem is the pit is made of clay and settling has caused hairline cracks in it and it no longer holds water. The water leaches out after a couple of days causing sewer gas to escape into the garage. It stinks! I tried to epoxy the cracks I could see but it didn't work. (Still leaks out) My question is: Are you aware of some sort of liner that I could install in the base of the pit? Is there some sort of material I could coat/seal the pit cracks or the entire pit with? I've asked a few plumbers and they say to try to seal it with silicone or replace the pit. I'd rather not have to replace the pit because it would involve cutting up the floor and would cost a lot of money. Your advice would be greatly appreciated.