Cistern = collects rain water from roof
Hauled Water Storage Tank = no rain water, just hauled water
THESE ARE TWO VERY DIFFERENT THINGS. Obviously rain water collected from the roof runs across bird shit, leaves, insects, tar, etc... and REQUIRES continuous disinfection and filtration to be considered safe for human consumption. HWST's do not collect ANY surface water and are essentially filled with "city water," which has already been disinfected and so therefore requires no additional treatment components. You need to be very certain which one you have. And the old "dumping some bleach in now and then" routine is not a reliable method for water disinfection.
Being that cisterns utilize surface water, it's pretty much the softest water you're going to find. Well water, in most areas, is "hard" due to dissolved minerals it contains. Most wells require a water softener system. All types of water systems have the pros and cons.
Me personally, I'd rather deal with a water softener and the earth's natural filtration capabilities than rely on mechanical components to keep my drinking water bacteriologically-safe.
Oh, and who should pay to have a tank filled?... whoever is using the water.