When (not if) my back goes out from time to time, I use my simple water lifting pole. It's about 5 feet long, with a hook on the end, which fits under the handle of the water jug. I put the jug on the ground. The hook fits under the handle. I put my foot on the other end of the pole, and I lift the water jug with the hook:
The jug then swings up into place for relatively easy filling. But a pump would be better, if you can spare the electricity. They also make a drill attachment that serves as a water pump -- you could use a cordless drill.
