There also can be a lot of evaporation. Usually that water isn’t free.
There are plenty of online calculators for that. I plugged in the numbers on one and it is not insignificant.
And if you’re someplace that has 4 seasons, you generally have to do a shut-down procedure for the winter. Or so I understand. That isn’t required in Phoenix, of course. I suspect that is a non-zero cost.
We have the 4 seasons but keep our pool open all year. Winter isn’t cold enough to demand it. Not that we are swimming in it past November or before April but our pool is as much a landscape feature as a pool. We don’t care to look at a tarp or 1/2 drained pool all winter.
JLC