Irrigation box, drainage box, or attenuation box, the box being a single piece box not composed or assembled from a plurality of parts into a single piece, but produced at once as a single piece, the box comprising as integral parts of the box: - a base having openings therein for passage of fluid into and/or out of the box; - side walls (5a, 5b, 5c, 5d) extending perpendicularly relative to the base, the side walls having openings therein for passage of fluid into and/or out of the box; - an open side which lies opposite the base, the open side being designed such that two of these boxes can be placed with the open sides towards one another and then be connected to one another to adopt an assembled condition; - columns (7, 7a, 7b) which extend vertically from the base towards the open side when the base is in a horizontal position; and - at least one connecting part (8, 8a, 8b) between one column which is positioned free from direct contact with one of the side walls and one column which is positioned in direct contact with one of the side walls (5a, 5b, 5c, 5d), the connecting part (8, 8a, 8b) being free from direct contact with the base, wherein the box comprises a plurality of such connecting parts and wherein a number of the connecting parts are oriented perpendicular to the orientation of the remaining number of connecting parts, the box further having male connector parts and female connector parts in equal numbers distributed over the ends of the columns, wherein at least one of the columns has partly a male connector part and partly a female connector part, such that the box is connectable to an identical box to adopt the assembled condition, the columns having female connector parts are connected by connecting parts which extend in a direction perpendicular to the direction into which connecting parts connecting columns having male connector parts extend. - a base having openings therein for passage of fluid into and/or out of the box; - side walls (5a, 5b, 5c, 5d) extending perpendicularly relative to the base, the side walls having openings therein for passage of fluid into and/or out of the box; - an open side which lies opposite the base, the open side being designed such that two of these boxes can be placed with the open sides towards one another and then be connected to one another to adopt an assembled condition; - columns (7, 7a, 7b) which extend vertically from the base towards the open side when the base is in a horizontal position; and - at least one connecting part (8, 8a, 8b) between one column which is positioned free from direct contact with one of the side walls and one column which is positioned in direct contact with one of the side walls (5a, 5b, 5c, 5d), the connecting part (8, 8a, 8b) being free from direct contact with the base, wherein the box comprises a plurality of such connecting parts and wherein a number of the connecting parts are oriented perpendicular to the orientation of the remaining number of connecting parts, the box further having male connector parts and female connector parts in equal numbers distributed over the ends of the columns, wherein at least one of the columns has partly a male connector part and partly a female connector part, such that the box is connectable to an identical box to adopt the assembled condition, the columns having female connector parts are connected by connecting parts which extend in a direction perpendicular to the direction into which connecting parts connecting columns having male connector parts extend.