mikes, Thanks for the post. I believe that you answered knight500's question well. I have been winterizing since the the late 90's for a large travel trailer and now my current park model and new 177SE. I stopped distributing RV antifreeze long ago and limit its use to just the p-traps and toilet. I never have sanitized, but I know a lot do. My water quality has been very good. I do use a Bria water filter container that I fill and keep in the refrigerator for drinking and coffee. I am a microbiologist and really get the sanitization thing and will resort to that it I see symptoms of poor water quality.
I use compressed air to blow out the water for winterizing. I am very methodical and blow the line dry. So far so good. Still I may try the bleach treatment next year. I have never heard of water-borne illness due to contaminated RV water, but if the water has a smell (like rotten eggs?) then the bleach treatment would be solution, but doing this every year? I guess it depends on the each persons' comfort level and knowledge of the risk.
2017 Retro 177SE 2015 Ford F150 2.7L Ecoboost