A few years back I forgot to drain my hot water tank after about a month the hot water tank had a bad sulfur small. So now I drain my hot water tank after after every trip. I also add a small amount of bleach into the water line the first trip of the year to get the RV antifreeze taste/smell out of the water lines. This is after I drain the antifreeze and re-route the water through the water heater.
Since the OP is hooked up to water permanantly, I would drain the hot water tank once a week and then add a small amount of bleach into the incoming water line.
