What a brilliant invention.
I was going to say: our council has recently gone in for recycling. We rang up and asked them not to give us a wheely bin for garden waste because we make our own compost. But they did. I am sure someone on this site uses their superfluous wheely bin to transport water around their plot. You could either use a syphon to deliver water directly to a plant (surely you would be allowed a short length of hose working on gravity?) or a dipper.
We have no water at all, and I use all sorts of containers that I fill at home and drive up to the site every now and then, all at once, and use it sparingly before taking them all home (by bicycle) to start again.