I have seen from cleaningspot a trolley system which is basically a glorified fast flow ro/ reel and di unit with a glorified price also, though the idea seems ideal.
To not need to haul around 1/2 a ton of water every working day. So basically you would be using the customers supply, taking along several fittings/hoses to connect to their tap.
I know a few of you have thought there would be issues with some customers about using their supply, though its not often that excessive amounts are needed for regular jobs, more than about 15-75ltrs for domestic even so many even offer to use their taps/hoses until you explain about the water.
The only thing i would think would be a compact enough trolley and marketting the importance of the purification process. The benefit being more space in your work vech, less fuel used without all the water, no need for static system. Disadvantages, changes in advertisement - informing customers of the need to use their supply. Differences in tds at different addresses.
It seems advantageous to use the water that is already in the pipes in the ground at every single customers house than what how we are presently operating. Is this the way of the future, i think i would prefer to do things this way.