Sanitizing Water Tank

A few comments on this. I use my RV alot, and I normally dry camp, so I fill my tanks regularly throughout the season. I sanitize my tank and system in the spring when I de-winterize. Of course that includes flushing fresh water through the system after the sanitizing process is complete. I always filter the water when I am filling my fresh tank because you should never trust a water source. I won't let it sit full for very long unless I am in one place and using it until empty. If it is unused for a couple of months I will sanitize my RV again, just to make sure I have no issues. I tow with very little water as it's easier on the RV. A friend of mine stores his RV full of water, non-chlorinated, and he develops problems when he goes on the road.