A plastic infiltration unit comprising: a top deck which extends in a plane, at least one pillar extending from the top deck for supporting the top deck, wherein: the top deck is provided with at least one integrated connector (3, 5) arranged to connect the plastic infiltration unit with another at least one integrated connector, of another plastic infiltration unit in a side by side arrangement, and a perimeter of the top deck comprises a plurality of edge regions (15, 17, 19, 21) including a plurality of edges, respectively, at least one of the plurality of edge regions (15, 17, 19, 21) is arranged to come into alignment with at least one edge region of the another plastic infiltration unit, each of the plurality of edges of the plastic infiltration unit and the another plastic infiltration unit is provided with at least one of said integrated connectors (3, 5), respectively, and the integrated connectors (3, 5) are arranged to connect with each other; wherein each of the plurality of edge regions (15, 17, 19, 21) is provided with an integrated male connector and an integrated female connector disposed as a pair of said integrated connectors, of which the female connector is arranged to connect with a male connector of the another plastic infiltration unit and the male connector is arranged to connect with a female connector of the another plastic infiltration unit, and the pairs of connectors are arranged on each edge region in a manner alternating, around the perimeter, between a male connector and a female connector, characterised in that the male connector is for being slotted into the female connector in the direction of the thickness of the top deck. a top deck which extends in a plane, at least one pillar extending from the top deck for supporting the top deck, wherein: the top deck is provided with at least one integrated connector (3, 5) arranged to connect the plastic infiltration unit with another at least one integrated connector, of another plastic infiltration unit in a side by side arrangement, and a perimeter of the top deck comprises a plurality of edge regions (15, 17, 19, 21) including a plurality of edges, respectively, at least one of the plurality of edge regions (15, 17, 19, 21) is arranged to come into alignment with at least one edge region of the another plastic infiltration unit, each of the plurality of edges of the plastic infiltration unit and the another plastic infiltration unit is provided with at least one of said integrated connectors (3, 5), respectively, and the integrated connectors (3, 5) are arranged to connect with each other; wherein each of the plurality of edge regions (15, 17, 19, 21) is provided with an integrated male connector and an integrated female connector disposed as a pair of said integrated connectors, of which the female connector is arranged to connect with a male connector of the another plastic infiltration unit and the male connector is arranged to connect with a female connector of the another plastic infiltration unit, and the pairs of connectors are arranged on each edge region in a manner alternating, around the perimeter, between a male connector and a female connector, the top deck is provided with at least one integrated connector (3, 5) arranged to connect the plastic infiltration unit with another at least one integrated connector, of another plastic infiltration unit in a side by side arrangement, and a perimeter of the top deck comprises a plurality of edge regions (15, 17, 19, 21) including a plurality of edges, respectively, at least one of the plurality of edge regions (15, 17, 19, 21) is arranged to come into alignment with at least one edge region of the another plastic infiltration unit, each of the plurality of edges of the plastic infiltration unit and the another plastic infiltration unit is provided with at least one of said integrated connectors (3, 5), respectively, and the integrated connectors (3, 5) are arranged to connect with each other; wherein each of the plurality of edge regions (15, 17, 19, 21) is provided with an integrated male connector and an integrated female connector disposed as a pair of said integrated connectors, of which the female connector is arranged to connect with a male connector of the another plastic infiltration unit and the male connector is arranged to connect with a female connector of the another plastic infiltration unit, and the pairs of connectors are arranged on each edge region in a manner alternating, around the perimeter, between a male connector and a female connector,