That depends on the load, as in wattage. I have used many BBU's, and I don't know of any that would provide power for that long a time with what I assume is a considerable load. This particular unit will run a high-end PC for about 10-15 mins. max on battery alone.
The best strategy would be to have an emergency generator that would kick in automatically, while the battery backup would keep the pump running for the few seconds it takes the generator to kick in.