In the autonomous region of Catalonia there are over 250 drinkable water treatment stations, 5 of which form part of the basic network supply Ter-Llobregat. Three different companies run these companies: ATLL Concesionaria, Aguas de Barcelona and Mina Pública de Aguas de Terrassa. In Catalonia, water treatment policies are under the jurisdiction of the city halls of each city. For this reason, the Catalan Agency of Water (Agencia Catalana de Agua) isn't involved in any policies that focus on how these stations are ran in the country.

There are two water treatment plants in Barcelona: Planta de Sant Joan Despí and Planta de tratamiento del Acuífero del Besós.