In early April of this year during days of rain, the water table rose and water began to enter my basement. No problem. I have a sump pump. Well in no time there was 1 foot of water on the basement floor because my sump pump quit on me. I found out too late. My hot water heater ( 40 gal. LP Ruud ) which is on a three inch cement pad was submersed up over the burner and pilot but below the gas valve. A repair man came in and cleaned out the burner unit ( he just blew into the assembly to clean it ). One month later: No hot water: pilot won't stay lit. Middle of May: no hot water: pilot out, repairman replaces thermocouple. Four days later: no hot water: pilot out and won't stay lit. Repairman comes and replaces orifice in the gas line. Two weeks later: no hot water: same problem. Gas valve now changed. Repairman tells me that he tested the old gas valve and "it was at
11". The new one is at "12". Anything better than 10 is good. Don't know what those numbers mean, but it sounds good I guess. Seems to me that the problem is going to come back again. I think ( and said it to the repairman ) that the burner itself may be the problem, I don't know. It was under water. Any guesses. ( The hot water heater itself is a '91 installation and repairman said it looks in very good shape).