They might have a tap, but turn it off in the winter. The tap might freeze in the winter, its not very professional relying on them, their facilities and whether or not they operate 365 days a year.
I think you'd be more open to them thinking how easy it is to set your own unit up and then dispense with your services. Just plug the unit on and away you go, simple isnt it, so simple I wonder how many custards would try it out for themselves.