[JRTJH]

I agree with Oak. You never really know when you'll be in a situation where the water gets turned off to the campground, someone does something "stupid" and creates a "boil water condition" in a part of the campground or even, it's going to freeze tonight so turn off the park faucet and unhook your hose, we're turning off the pump so there'll be no water in the campground after 6PM.

So, in situations like these, it's either "you'll be dry" or use your fresh water tank.

I'd sanitize the entire system and not worry about it. It's an easy process, you'll REALLY want to sanitize the water lines anyway, since you'll be leaving the bleach in those lines for 24 hours, why not just do the FW tank at the same time so you're ready for whatever comes along. After all, holding water in the trailer is one of the reasons we buy RV's (being able to remain independent of campground hookups) so might as well be ready....