I have a 40 gallon water heater with copper pipes in the house. My problem is very low hot water pressure. The cold seems to be working fine. I also seem to run out of hot water fairly quickly while showering. This is a U.S. Craftmaster water heater that looks to be fairly new, though, I just bought the house about 4 months ago so I really have no idea to its age . Any help as to what is the problem is, would be greatly appreciated. Thank you.