This is mine
I drilled a small hole near the top of the tank and fitted the inlet spigot through the wall of the tank. This was so I could attach a float valve on the inside. The tank is set up on a wooden frame (made from 4"x4" timber to take the weight) so i could put a 25lt bottle under the outlet tap to fill it.
Now I have two IBC's side by side and joined by a pipe from one tap to the other, so I have in effect a 2000lt tank. There is a submersible pump in one of them and a pipe to the outside of my shed to fill the van tank. Because the IBC's are high up, all I have to do is start the water flowing then switch off the pump and the water syphons into the van tank.
My first IBC was brand new, but the second is used. I washed it out with tap water and left it at an angle to drain all the water out. I never had any trouble with water quality.
Cheers,
Ian