The Spanish government launched an investigation after it emerged that an energy company drained two reservoirs during a heat wave and drought in order to profit from exceptionally high electricity prices.
Iberdrola, the country's second-largest electricity producer, drained reservoirs in the provinces of Zamora and Cáceres in western Spain for weeks to produce cheap hydroelectricity at an all-time high price for consumers.
Air conditioners and fans are running at full capacity as Spain is still in the grip of the heatwave. On Saturday, Andalusia's Cordoba recorded the highest temperature in the country's history at 47.2C (117F).
Ecological Transition Minister Teresa Ribera called Iberdrola's actions scandalous and sent a letter to the company.
"This cannot be allowed," she said in a television interview. "Water is a scarce resource that is as important for the well-being of families and the economy as it is for generating electricity."
Ribera said she believed Iberdrola's actions are irresponsible, but they are not illegalbecause the company is allowed to use a fixed amount of water per year, whenever it wants and regardless of climatic conditions.
"It's legal, but not reasonable, so we want to intervene as soon as possible," she said.
Both reservoirs are far from the sea and were popular for swimming and boating, especially during the hot summer months. They have now become a desert, according to Javier Aguado, mayor of San Sebrian de Castro, one of the affected villages.