If there is no rain like last weekend in the coming weeks, the Barcelona metropolitan region will face an unprecedented situation. Both the government and water companies are preparing for the possibility that tap water can no longer be considered drinkable if it exceeds certain indicators.
The newspaper El Periódico writes this based on collected data. The indicators under discussion have been established by Royal Decree 3/2023. Recent rainfall has increased water reserves. As a result, the reservoirs now have an extra month’s margin. But summer is approaching and the irrigation season for the agricultural sector begins. This endangers the quality of the water that supplies Barcelona and the surrounding area.
More than half of the water no longer comes from reservoirs
In some cities in Catalonia, the low amount of water in reservoirs and aquifers has already led to the concentration of pollutants in the water network. 55% of the water consumed in Catalonia no longer comes from reservoirs. Instead, it comes from regenerators, water treatment plants and desalination plants.
Higher concentration of pollutants
The decrease in better quality water from the reservoirs results in pollutants becoming more concentrated due to the reduced amount of water overall. Miren López de Alda, researcher at the Higher Centre for Scientific Research (CSIC), explains that the high presence of organic matter or sludge and the surplus of disinfectants pose a problem for both the water from the reservoirs and the groundwater. Despite the advanced water purification installations, purifying all the water may not be possible.
Limit on what is possible
So far, the water treatment plants of the Ter and Llobregat rivers, which supply Barcelona with water, have been able to purify the water supplied. However, despite continuous improvements, there is a limit to what is possible. The treatment plant in Cardedeu treats water from the Sau and Susqueda reservoirs but is awaiting improvement works. These must offer more guarantees for the purification of all water. However, these works will not be completed before the summer.
Low water level in the river
The situation around the Llobregat is more complex. The main water treatment plants are located in Abrera and Sant Joan Despí. The last of these is one of Europe’s most modern and advanced. The water collected here, a mix of reservoir water and regenerated water (additionally purified wastewater) from El Prat de Llobregat, is more difficult to purify due to the low water level in the Llobregat river, resulting in poorer quality than the water from the reservoirs.
In addition, before mixing with the regenerated water, the river water contains lower-quality water from the Monistrol, Abrera and Martorell water treatment plants. This does not contribute to improving the situation.
Increasing salt intrusion
The current water crisis also complicates the situation in underground water masses, which are experiencing increasing salt intrusion. This can lead to a situation where the water, which serves as a “lung” for the treatment plant, becomes unusable. Such a situation would potentially affect millions of people. To solve these, high-quality water would be needed to dilute the current water. Only in this way can it remain within the permitted limits.
Tap water is not for drinking or cooking
If water in Barcelona exceeds permitted limits, the population is advised not to drink it or use it for cooking. This scenario would mean that the water exceeds certain regulatory thresholds, such as for chlorides or trihalomethanes. According to the experts cited in El Periódico, it does not mean that the water poses a health risk.
