I agree with the other guys, this is not a good idea. In my country water is a rare resource and in many cities it is now illegal to use a garden hose to wash the car or water the garden. To fill a swimming pool involves ordering a tanker load of water, not cheap.
While it shows some clever lateral thinking, using water in this way is a waste of some one elses power and could be called stealing.
I think sometimes there is confusion between renewable power and free/cheap power. Using the wind or sun to provide your power is renewable, ever lasting and good for the planet. But, as an example that pops up here from time to time, burning used engine oil to make your power, while cheap, is not renewable or good for the planet.
Glenn