I was away from my house for about 6 weeks and came home to a flooded basement. While I was gone the city turned my water off for excessive use (370,000 gallons in 30 days). Here is the problem, I turned the water back on and there is no water leaking. There is no sign of breaking, no sink faucets were turned on and all drains are clear including toilets. The only thing I've found is the water heater pressure relief valve is dripping. Does anybody have any ideas?

Thanks

If the heaters P&V valve emptys in the basement and you have a backflow preventer but no expansion tank then pressure coiuld have built up in the heater and tripped the T&P valve flooding your basement before the city shut you down. If this is the case ( and unless I've missed something this is about all that it could be) the answer would be to install a expansion tank on the heater cold water supply. Let me know. Tom

If the heaters P&V valve emptys in the basement and you have a backflow preventer but no expansion tank then pressure coiuld have built up in the heater and tripped the T&P valve flooding your basement before the city shut you down. If this is the case ( and unless I've missed something this is about all that it could be) the answer would be to install a expansion tank on the heater cold water supply. Let me know. Tom

Thank You Tom, I am thinking the same thing. Do you think the valve stayed open until the water was shut off? (Over 370,000 gallons in under 30 days) Now that the basement has been completely stripped of carpet and sheetrock I've left the water on and used no hot water (staying in a hotel) nothing has happened, except a slow leak from the T&P valve (real slow 1 or 2 drip a minute). I am going to replace the valve (no problem) and next time I leave turn the water and water heater off. My concern now is will what will the insurance company say? Again Thank You Tom

The cheapest insurance homeowners can have is shutting off the water when they leave on vacation. Even a tiny pressure leak can flood a house if left long enough. I think the heater built up pressure tripping the T&P valve as the only outlet. You didn't say, but do you have a sprinkler system? A backflow preventer out near the meter and no expansion tank on the heater cold water inlet?" The only thing you can do with the do with the insurance company is present them with the facts and see what they have to say. Good luck, Tom