The integrated water cycle


Transport of waste water through the urban drainage networks and return to the rivers in optimal conditions.

Includes the transport of the waste water through urban drainage networks to the waste water treatment plants (WWTP) and the subsequent purification of this water in order to return it to the rivers in good condition.

The urban drainage system is unitary and is composed of collectors, outfalls and conduits. The sanitation system also includes storm tanks, retention tanks and waste water pumping stations (WWPS).

Reclaimed water is purified waste water that has been subjected to an additional or complementary process to make its quality suitable for its use in irrigation of green areas, sports facilities and certain industrial uses.

Read a PDF about sanitation

Relevant data

13,727 km network of culverts

791 km collectors and outfalls

63 storm tanks

126 waste water pumping stations

156 waste water treatment plants

510 km reclaimed water network

33 reclaimed water tanks

Did you know …?


The prehistoric towns of ancient Crete had sewage culverts.

The first WWTP in the region dates from 1932, it is called La China and is located in Madrid.

The purified waste water undergoes a specific treatment that allows its reuse in the irrigation of parks and street cleaning.