Water heater leak

My parents' house is over about 25 yrs old and I was planning to spend some days over there after slight renovation work. During the renovation process, I discovered the floor in the bathroom is warm and the wall of the bathroom is also warm. I suspect there is a leak under the floor from the water heater line towards the ground bathroom. However, the hot water supply towards the ground area was carried out through a copper pipe. I suspect any pinhole leak that occurs to the copper pipe. How to resolve the issue. Whether we want to replace the water heater in the garage since it is an old one. Please share your thought and suggestion on this issue
Thanks!

Unless the area is wet I would first think about if there are any ductwork routed in those areas. Just the presence of duct work will warm floors and walls in which they are routed under or behind.
Also if a duct work has gaps that also will increase the heat loss behind those areas.

An inspector with thermal imaging may be able to help "see" the concern.

jtroth wrote:Unless the area is wet I would first think about if there are any ductwork routed in those areas. Just the presence of duct work will warm floors and walls in which they are routed under or behind.
Also if a duct work has gaps that also will increase the heat loss behind those areas.

An inspector with thermal imaging may be able to help "see" the concern.

Definitely good insight on to the situation. I wouldn't rush to suspect a leak without looking for other signs. Even a pinhole leak is going to let a lot of water out in a short amount of time. As jtroth stated, get with an inspector that has a thermal camera. I'd also want to put a moisture meter on it. You can pick a cheap one up at a local home improvement store for fairly cheap. While it's not as good as more expensive ones, it'll certainly tell you if there is a high moisture content in the wall should it have soaked through.

I didn't have a picture of an HVAC vent running behind a wall, but I'll add a picture of radiant heat and show how valuable thermal imaging can be as a tool in the arsenal.

Here is a thermal that indicates a likely hvac duct work that is leaking