On Jan 27, 4:29*pm, Briggs wrote:
We have a rental house that sat empty for several months. *During that
time, I left the gas water heater on the "Vacation" setting, to keep the
* pilot lit, and keep some warmth in the pipes during what passes for
"cold" weather in the NW. *Now there is a strong sulphur odor from the
hot water. *A renter has only just moved in, so I'm not sure yet if the
odor will go away with regular use. *If not, should I drain the tank, or
are there other things I should try?

If something started growing in the tank from a cool, warm temp,
getting the tank hot for a few days should kill anything, maybe 130f
-140f, turn it on high.