Running Water and the Modern City

In 1891, the City Council planned a pumping station in Trinitat to lift and channel water from the Montcada mine. The project was entrusted to the architect Pere Falqués i Urpí. The result was a complex of Modernista buildings (1915–1917), some single-story and others with basements. When Avinguda Meridiana was opened, the water treatment pavilion and the adjacent house ended up in Trinitat Nova, while the pumping pavilion and the caretaker's house remained in Trinitat Vella. Casa de l'Aigua is one of the heritage sites of the Barcelona History Museum. When the first air raids on Trinitat Vella began, residents used the underground facilities of Casa de l'Aigua, a pumping station that lifted and channelled water from the Montcada mine, as a shelter. The neighbourhood was located between several military targets: the Sant Andreu artillery barracks, Casa de l'Aigua and the Puigcerdà railway line. One of the first air raids on the neighbourhood took place on 25 July 1937, carried out by six or seven planes from the base in Mallorca. During these early air raids, the Tres Ulls bridge, now buried underground, was also used as a shelter; it provided access to the underground gallery connecting Casa de l'Aigua in Trinitat Vella with the water treatment pavilion in what is now Trinitat Nova. Later on, residents mobilised to build shelters closer to their homes, as Casa de l'Aigua was quite far away. About seventeen shelters were built in Trinitat Vella during the war.

A building serving the neighbourhood

Casa de l'Aigua is a facility in evolution; it is currently undergoing consolidation and expansion as a museum and cultural space. The project involves restoring the industrial heritage complex (1915–1919) alongside urban improvements and the redevelopment of the surrounding area.

It is one of the sites of the Barcelona History Museum and functions as a "museum-laboratory," hosting activities, tours, and exhibitions linked to water and the city.

In April 2026, the Ròmul Gavarró collection (related to water usage) was added to the site.