A water purification and storage system comprises a water storage container, a covering plate and an impermeable wall. The water storage container is formed by a plurality of tangentially connected polygonal water-filtering wells (1). Well walls of the water-filtering wells (1) are of a water-permeable structure, and an impermeable layer (4) is arranged at the bottom of the well, wherein at least one of the water-filtering wells (1) is a water output well (14). The covering plate (2) is arranged at the upper portion of the water storage container, and comprises an impermeable covering plate (21) arranged at the upper portion of the water output well (14) and a water-permeable covering plates (22) arranged at the upper portions of the remaining water-filtering wells. The impermeable wall (3) is arranged around the water storage container. The water purification and storage system is suitable for the collection and purification of rain water. Also disclosed are a water-filtering well (1) for use in the water purification and storage system, and a polygonal building block (12) for building around the water-filtering well (1).