1. Water: what evaporation quietly costs
Evaporation is how a pool in Spain loses most of its water, and it runs fastest in the conditions you moved here for: long sun, warm nights and a little wind across the surface. It is invisible because it is gradual — nobody watches the level drop, they notice the automatic filler running.
At Spanish mains prices — roughly €1.50 to €3 a cubic metre, depending on the municipality — a standard 8 by 4 metre pool spends something like €22 to €75 a year on replacement water. That is the smallest of the five bills and on its own would justify nothing. A closed automatic cover cuts evaporation by roughly 70 to 80 per cent, so most of it disappears.
What has changed lately is not the price but the permission. Several Spanish municipalities now restrict filling and topping up during drought episodes, so the real constraint is no longer only what water costs but whether you are allowed to buy it in the month you need it. A pool that barely loses water never has to ask.

