I have been in my house for two years. The hot water heater is located inside in a bathroom. The pressure release valve on the side is connected to a pipe which runs out to the back of house. When I first got to the house, there was some water going through the pipe. It quickly got to be a steady trickle. I had the valve replaced which helped a lot, but I occasionally still had some water drip through, primarily during cold weather. I recently had a new hot water heater installed, and thought that would be the end of it. But now that it has turned cold, I once again have water dripping through the pipe sometimes. What would cause this problem with both water heaters??

Occasionally, When I flush the toilet in my bathroom, I hear a gurgling sound/noise which appears to be coming from my bathtub drain. Is this anything to be concerned about? Thanks.