Water System

We have recently purchased our 2008 AS and have been out a few times for weekends. Twice at KOA's where we had full hookups and twice at state campgrounds where we boon-docked. Last weekend, we sanitized the water system, and then this weekend we were in a state park using the on board fresh water. We won't be going out again for a couple of weeks - again to a state park where we will only have electric hookup. My questions are: 1) fresh water tank - should we drain (about 1/2 full now), 2) having just sanitized, the system should be good for the rest of the year - correct? (assuming we don't accidently introduce something.), 3) how long can the AS safely sit(water safety) between uses?



Thanks ahead of time for replies.