Water-saving device

The utility model discloses a water-saving device for building construction, which comprises a base, the top of the base is sequentially provided with a settling box body and a filtering box body from bottom to top, the center of the outer wall of one side of the settling box body is provided with a fixing plate, the inner side wall of the fixing plate is fixedly provided with a settling box communicated with the inner cavity of the settling box body, and a filtering plate is arranged below the settling box. The filter plate comprises a precipitation plate layer, an activated carbon plate layer and a calcium-plastic plate layer which are sequentially arranged from top to bottom; a filter box matched with the filter box in size is arranged in an inner cavity of the filter box, a cover plate is arranged at the top end of the filter box, and a flange plate is fixedly connected to the center of the cover plate. According to the utility model, sewage generated in building construction can be purified, so that seco