Two Questions (Sanitize and Empty Tank)

Muddydogs wrote:
... Most city's chlorinate the crud out of there water which in turn is going into your holding tank taking care of anything that might be in there.

Um, not so. Yes, they chlorinate, but the residual is only barely enough to deliver "sanitized" water to your tap, if there is any at all. As a pool owner, I test to keep my pool at 2-3 parts per million of chlorine. Tap water tests out at zero. Probably not actually zero, but the test kit doesn't measure such minute amounts. Case in point - on a warm day, if I fill the pool using municipal water, it can cloud up in as little as a half-day from bacteria, if I don't add additional chlorine. RV systems aren't open to the world, so there is little contamination to encourage growth, but neither is there anything left in tap water to discourage it, either.

BTW - fun fact: Chlorine itself has a pretty weak smell. When it combines with other chemicals ("bugs", etc.) it produces chloramines, which have a very strong smell. That's one of the clues that a swimming pool needs MORE chlorine, as the active stuff has been used up. It's easy to get to very unsafe levels in a pool ("shocking' the pool), and not have any smell at all.
In the RV case, smelling it coming out of your taps is the indicator that it's done it's job. And yes, regular bleach smells, because due to dilution, storage, and age it already has formed some chloramines in the bottle, along with the more concentrated "active" chlorine.