I am trying to find internal water tanks for my soft plumbed espresso stand. Where can I find those tanks that you refill everyday and you have about 2-3 depending on the coffee stand. I cannot find them anywhere!
Just google potable water tanks, you'll find them just about anywhere. Remember potable not portable there is a huge difference.
Otherwise I would just use a 5 gallon water jug from the store and a flojet bottle pump. On the side of the pump is usually a 3/8 John Guest fitting where you can directly connect your espresso machine to.
We find a good source of Potable water containers is your local camping store. Make sure your pipework and fittings are "Potable" too.
We had a customer who moved a new water boiler a while back to a new position. He phoned complaining that the water tasted awful - he had joined a couple of pipes together that were meant for a washing machine. Trouble was, he refused to believe that cold water moving through these pipes would change the flavour. Changing the pipes proved the point.