In Kosovo and had local nationals would bring us our shower water and such. Anyway they came in one day with a big water truck labeled "potable water" and filled our shower tank, not sure how many gallons but it was around 15 wide and 10 feet tall, and continued filling the other tanks. They got to the end, peeled off the magnetic "potable water" sticker and slapped on a "nonpotable water" sticker, and proceeded back our way sucking out the gray water tanks. After we saw that it wasn't common to see someone go to the shower with a carton of drinking water. That water was also used for the sinks and toilets. They did warn us not to drink the water.