First... I have not and would not.. The reason... Sometimes I need hot water AND Air conditioning at the same time and the campground where Im' parked 30 amps may not allow that if the day is too hot or cold (Air conditioning includes heating) I've tripped the )(@#$ breaker many times, when this happens Propane is nice.
However if you are one of those who wishes to eliminate propane.. No problem.
Water heaters come in 3 types
Dual fuel (Propane electric)
If yours is dual fuel, simply shut off the propane
IF it is propane only Hott-Rod, this is an electric element that replaces your drain plug/anode.
Followoing link chosen at random from a GOOGLE list:
Hott Rod XP :: Diamond Group