Keeping Water in My Freshwater Tank During Storage?

I drain mine in storage, but I own the building where its stored. When ready to hit the road, I add about 1/3 tank, but I don't treat it. I only use it for the toilet and the shower and only while in transit. I always stay at FHU CGs and hook up to water then. For cooking, drinking and soaking my teeth, I buy gallon jugs of distilled water all the time. The outside of me is waterproof.

Yes.
City water is treated.
I usually dump and re-fill before leaving.

A web search will come up with a number of hits for treating well water with common bleach.

Always some fresh water in our tank.

My tank is always full regardless.
This is Earthquake country

Moved from Technology Corner

I use treated city water and have left water in the tank over a month and it is still good.

At home we might be a month between outings but we fill with city water that has been chlorinated/fluorinated? so we think it is OK to keep the tank full. If your tank has been sanitized at the beginning of the season and the water you add is `OK' I'd go for it.