The Socialist government, which initially opposed water transfers from one region to another, executed a political U-turn and allowed water to be pumped into Catalonia from the river Ebro in the neighbouring region of Aragon.
The move infuriated southern regions such as Murcia and Valencia, which asked for similar concessions. Both are significant agricultural areas, with a busy tourist season about to start, and expect their water supplies to be hit hard.
Meanwhile, despite heavy rainfall over the weekend water reserves in Catalonia only increased by 1.7%.
The Socialist government is following a controversial programme of building desalinisation plants, which they claim will provide a long-term solution to Spain's endemic water shortage. They have built six so far and plan a further 18. One is due to open outside Barcelona in May next year.
Ramón Llamas, a water expert at Madrid University, says Spain squanders its water and needs better soil management, adding that despite having one of the lowest amounts of rainfall in western Europe, it has one of the highest levels of water consumption a head: the average person in Madrid uses 140 litres a day.