From time to time I have to refill my swimming pool due to evaporation.
Sometimes when I know a big storm is coming I will open the drain and let it drain an additional 8" and I will fill it back up to the proper level after the storm passes.
I have always used the garden hose to do that and just turn on the water.
I also have a well pump that is hooked up to the sprinkler system. On the well pump is a spigot, I never used it, but I could connect the garden hose to it, turn the valve off to the sprinkler line and use the well water to fill the pool.
I will save on the water bill...but I will pay more for the electric consumption to run the pool. I am not sure which one yields more cost savings.
My pool is 25000 gallons. It's depth varies from 3 to 9 feet so I would assume an average depth of 6 feet, so on average, to fill one inch of my pool is around 350 gallons. To fill 10 inches is 3500 gallons.
I don't know if it matters, just more or less curious. I guess my well water would also be harder with more minerals.
MC