laknox, when we fill our water tank, we also turn on the pump while it's filling to purge the air from the hot water heater and the other lines. That way, you also get the hot water tank filled when filling the fresh water tank. At least that's what we have done since 1993 with no problems. We do sanitize the freshwater system before its first use of the year but not after that. We have been drinking water from our fresh water tanks for over 22 years with no ill effects so don't worry about that, just remember to sanitize before you use it.