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