RAIN OVERFLOW BASIN FOR COLLECTING AND STORING WATER

A rain overflow basin (1) for collecting and storing water, in particular rainwater, mixed water, or wastewater, having an inflow (2), an outflow (3), at least one basin chamber (5), at least one basin spillway (7), which is equipped with a weir threshold (6) and is connected downstream of the basin chamber (5), at least one drain (4), which discharges the basin spillway (7), and a purification device for purifying the water flowing from the basin chamber (5) to the basin spillway (7), wherein a retention wall (8) is provided between basin chamber (5) and basin spillway (7), which is used to dam up water accumulating in the basin chamber (5), a storage space (10) is provided between the retention wall (8) and the weir threshold (6), in which water draining from the basin chamber (5) is dammed up, to reach the basin spillway (7) via the weir threshold (6), a passage opening (9) is provided in the retention wall (8), and a movement-fixed retention element (11) is provided as a purification device, which extends into the basin chamber (5) such that water draining from the basin chamber (5) through the passage opening (9) into the storage space (10) flows through the retention element (11).