The desalination plants have saved the water supply over the summer in Alicante and Murcia.
The Partido Popular is supporting the plants, because of a break down in the Tajo water transfer pipe.
They are putting the facilities which were being criticised at 100% production.
The desalination plants can supply three million people in the tourist season.
In July the production of desalinated water was 20 times of last July.
The European Commission paid for a large part of the construction, but some other plants, projected for the real estate boom are now inactive.