Description A-AST-1500-2, Double compartment 1500 Gallon Two Compartment Plastic Septic Tank. This plastic septic tank is 58" wide, 137" in length and 72" tall. This septic tank has been specifically designed to meet wastewater treatment standards. This Ace Plastic Septic Tank is manufactured from (HDPE) High Density Polyethylene and has a specific gravity of 1.7.Capacity: 1500 GallonsDimensions: 137"L x 58"W x 72"H