Mina d'aigua del Masnou

Mina d'aigua del Masnou is a network of underground water galleries beneath the coastal town of El Masnou, in the Maresme region, a short train ride northeast of Barcelona. For roughly two centuries these hand-dug tunnels supplied the town with drinking water, and a small section is now open to visitors as a heritage site.

What exactly is a "mina d'aigua"?

Despite the name, this isn't a mine in the sense of mineral extraction. It's a system of narrow underground channels, carved by hand through rock and clay, designed to intercept groundwater seeping through the subsoil and carry it by gravity to wells, cisterns and public fountains around town. Excavation began in the 18th century, when El Masnou's growing population needed a dependable water supply and the surrounding hills offered no surface springs. Over time the network expanded into 28 separate galleries, adding up to roughly 27 kilometers of passages running beneath the entire town.

How long was the system in use?

The galleries remained the town's main water source until the 1960s–70s, when a municipal piped water service finally took over. Before that, during the Spanish Civil War, sections of the tunnels doubled as air-raid shelters — their depth and branching layout gave residents a genuinely safe place to wait out bombing raids. Once the water system was decommissioned, many stretches were forgotten, and some were sealed or filled in over the following decades.

What will you actually see on a visit?

Visits start at the Water Mine Interpretation Centre on Plaça d'Ocata, housed in a restored former butcher's shop that opened to the public in 2019. Inside, a reconstructed courtyard with a traditional stone washbasin sets the scene, alongside displays of tools and objects tied to building and running the network. From there, a stairway leads down into an accessible stretch of the Cresta and Malet galleries — about 40 meters of tunnel where you can see the original rock-cut walls, the channels that carried the water, and traces of two-century-old excavation work. The temperature underground stays constant year-round and the air is often damp, so dress accordingly.

How do you get there, and when's the best time to go?

El Masnou sits on the Maresme coast and connects easily to Barcelona by regional Rodalies trains, with journeys taking around 20–25 minutes. From the station, it's a short walk of a few minutes along the seafront to Plaça d'Ocata and the interpretation centre. The tunnel itself is only open through scheduled guided visits with limited capacity, so booking ahead through the Masnou Nautical Museum — which manages the site — is essential. Pair the visit with a stroll through the old town centre and the seaside promenade; El Masnou is small enough to see comfortably in a few hours.

Frequently Asked Questions

Do I need to book in advance to visit the water mine? Yes. Access is only through scheduled guided tours with limited spots, arranged in advance through the Masnou Nautical Museum, which coordinates all visits to the site.

How long does the visit take and what's included? A visit covers the interpretation centre on Plaça d'Ocata plus a walk through roughly 40 meters of the accessible Cresta and Malet galleries — the whole thing typically takes about an hour.

Is the site suitable for children? Yes, the accessible section is safe and set up for family visits, though the passages are narrow, damp, and without natural light, so plan accordingly.

How is a water mine different from an ordinary mine? A mina d'aigua was never used to extract minerals — it's a purely hydraulic structure, built solely to capture groundwater and channel it into the town's drinking-water supply.