My home is on a concrete slab with my boiler and hot water heater on the second floor. Heater and boiler are in good condition, less than ten years old. In the month of March, by water bill was unusually high. Yesterday, I had a local plumber in to evaluate my problem, and he determined the leak is coming from somewhere in the hot water line coming out from the boiler. He has proposed running new lines throughout the house using what is called PEX tubing. I had him place a shut off valve on this line to allow me the time to make a carefully thought out decision without having to rush. Obviously, I want to get other opinions. I really liked the plumbing/heating guy that did my heater back in 08. I am hoping that he can come in next week for his opinion, and he may know the layout since he did 2 bathrooms, and the heating system. Because I have an engineered hardwood over the slab, I cannot see where the leak is occurring. Since it is in the hot water lines, it would have to be to a bathroom or a kitchen. At present, there is an area in the kitchen that does feel warm as you walk over it in bare feet. What makes the issue more complicated is that I have radiant heat in this slab as well. I certainly am not about to have the slab jackhammered to repair a leak, with the possibility of destroying my heat as well. Replacing he flooring is not an issue, since there has been some other damage. As of now, I have not put a claim on my homeowners, but am trying to get more information before doing so. I have a company called American leak detection coming out next week. Their rates are not cheap, but they claim to be able to find where the leak is occurring. My wife is concerned their could be structural damage from wherever this water is going. My thought is that having documented the leak could help me if I did decide to make a claim. Is anyone familiar with anything like this?