If this situation does not change and the effects of climate change in Spain are not reversed, in 2025 the percentage of water lost will rise to 25 percent.
Droughts and floods will also reportedly increase in the coming years.
Julia Martínez, author of the study "The effects of climate change on the risk of floods in Spain", points out that the Mediterranean coastline, the Canary Islands and the Basque Country are the regions most at risk of these extreme weather events.
The NGO warns that these are not "predictions", but "real data" that reflect a situation that is already occurring.
"It must be taken into account that the 20 percent we manage is the average water reduction of the entire country, but in areas such as the Mediterranean basin, up to 40 percent has been lost," warned Santiago Martín Barajas, Head of Water of Ecologists in Action.
The organization points out two causes that have led Spain to this situation.
On the one hand, the reduction in rainfall and, on the other, the rise in temperatures.
On the contrary, the demand for water consumption is growing according to the hydrological plans approved by the central government.
These plans estimate a 10 percent rise in consumption, mainly for irrigation.
"If the amount of water drops and consumption rises, there will be a water collapse," warned Martín Barajas, who proposes to reduce irrigated areas and take measures against climate change.