keeping the fresh water tank sanitary over the winter

It is recommended to sanitize the fresh tank at the beginning of every season. IIRC, recommendations are for 1/4 cup bleach mixed into the fresh tank with 10-20 gallons of water, run water through all water lines, let sit for a few hours or overnight, then dump. Fill tank with fresh water and cycle water through lines.

I do not recall ever reading to sanitize fresh tank or water lines prior to winterizing... and if using pink stuff in the lines, better to sanitize at the beginning of the season.