Deborah Cater
Spain’s power grid is tightly linked with its essential services, and Monday’s blackout showed just how they can be affected. The country’s water supply is critically dependent on electricity. While emergency systems can offer temporary relief, a sustained power outage has the potential to collapse the entire water cycle. This in turn puts public health at serious risk.
During Monday’s blackout (28 April 2025), some residents across Spain experienced significant drops in water pressure, while others faced near-total service cuts. In metropolitan Barcelona, water supply failures were reported in high-lying areas just below the Collserola range, particularly between the Llobregat and Besòs rivers.
Aigües de Barcelona confirmed the water supply was disrupted in neighbourhoods at the city’s highest elevations. In Badalona, Mayor Xavier García Albiol said the districts of Canyet and Montigalà were affected.
“At this moment, we have restored the water service in most of the network that had been affected,” the utility stated at 08:00 on 29 April. “Although some higher areas may still experience some issues, the service is expected to return to normal over the next hour.”
Concern over the supply led to widespread panic-buying of bottled water and other basic provisions in the afternoon and evening of 28 April. Reports from several major cities, including Valencia, Zaragoza, Madrid and Seville, noted supermarkets in affected areas were experiencing long queues and empty shelves. Bottled water was one of the most sought-after items. Some shops placed temporary limits on purchases per customer as fears grew over how long the disruption would last.
Why are water services affected?
The explanation for these disruptions is simple. Electric pumps are essential to almost every stage of the water supply. They extract water from underground wells and rivers, move it through treatment plants, and push it through distribution networks to homes and businesses. When the power fails, these pumps stop working. Backup generators can buy time, but only a few hours or days at the most. Once fuel supplies run out, the water stops flowing.
The first systems to fail in a prolonged outage would be water collection stations. Without electricity, groundwater pumps and surface water extraction points cease. Treatment plants would quickly run out of raw water to purify. Even if some reserves remain in tanks, the shutdown of filtration, sedimentation, and chlorination processes would prevent safe water delivery. Contaminated water, invisible to the eye, could start flowing into households.
The distribution network would also buckle under pressure, or rather, from the lack of it. Pumps that maintain flow through the primary and secondary networks would fail, especially impacting higher floors of buildings, homes reliant on rooftop tanks, and elevated neighbourhoods. As pressure drops, the risk of external contaminants entering the system increases.
However, perhaps the most worrying of all is the next stage – the collapse of the sanitation infrastructure. Wastewater treatment plants and pumping stations also depend on electric systems. When they shut down, sewage can overflow into streets and homes, creating new public health hazards. The failure of automated chlorination compounds the problem as even water stored in tanks could become unsafe.
Monday’s blackout was long enough to expose a vital vulnerability in Spain’s infrastructure.
Also read: Spain exports more electricity than ever thanks to green energy