The HydroStor HS180 has an installed storage capacity of 180 cu ft per chamber, and the HydroStor HS75 has an installed storage capacity of 75 cu ft per chamber. Both meet or exceed ASTM F2418 product standards and ASTM F2787 design standards, and are injection molded from high performance polypropylene. These storm water chambers provide maximum land utilization and minimal environmental impact with a small footprint and low installed cost.