Hot water heater not heating. Diagnose and find leaking water heater. 9 year old American Standard water heater. Recommend replacement Rheem tank water heater, or Navien tankless water heater. Average water heater life span is 8-12 years old. Install new Rheem tank water heater with new pan and test for functionality. Recommend Gemline water softener to protect new water heater from hard water damage.