Call for leak from shower head. Arrived and inspected shower head. Ms. Tariq states that the drip has started about 1 week ago, and has gotten worse. They have been in the home approximately one year. I checked the water pressure at the water heater, and found pressure to read at ~55psi at 1pm. While checking pressure, I noticed that there were rust and leak signs on the side of the water heater. I checked this out and found no active leak. It appears that the leak was likely from a previous thermal expansion tank. The pressure regulating valve has been replaced within the last year. My findings lead me to believe that the pressure regulating valve has been bad for some time (Ms. Tariq states that it was covered over behind finished drywall). With a bad pressure regulating valve, the prior thermal expansion tank above the water heater failed, and at some point after the bladder ruptured it rusted through and leaks for a significant amount of time (based on rust deposits on top of