Called out for low water pressure in the home. Found that prv was bad and also from 2005. Found that water heater also had no expansion tank. Turned off water and drained it down. Cut out old prv and installed new watts prv and new main shutoff. Also removed supply line on cold side of water heater and hard piped it. Cut in a new expansion tank as well. Restored water and checked for leaks. No leaks were found. Cleaned work area.