Abstract: A water collecting and distributing apparatus capable of collecting filtrate, distributing raw water, supplying back wash water and dispersing scouring air, which is disposed in a lower portion of a high speed filter basin, is disclosed. This apparatus comprises a plurality of blocks regularly arranged in the bottom portion of the filter basin, each block having a flow passage for air and water in the central portion thereof and a water dispersing chamber located adjacent to the flow passage. A communication hole is formed in a partition wall between the flow passage and the water dispersing chamber, and an injection hole is formed in each of the top wall of the flow passage and the top wall of the water dispersing chamber. The numbers and diameters of the communication holes and injection holes in the blocks and positions of these holes are arranged so that a certain relation is established among them. In each block, the flow passage is formed to have a trapezoidal sectional shape.