1000 Gallon Plastic Septic Tank Ace Roto-Mold septic tanks are stronger, easier to install, and less costly than old-fashioned concrete septic tanks- yet they still offer the quality construction and safety you expect. Manufactured from high-density polyethylene with U.V. inhibitors, Ace Roto-Mold tanks utilize a horizontal flow designed for below ground installations up to 36 inches. Ace Tanks are IAPMO approved and have passed strenuous stress tests. Each tank carries an individual serial code and is fully document from date of manufacture. Ace Roto-Mold septic tanks are designed and manufactured with rigorous quality controls. The trapezoidal deep-rib design and interior baffle system make Ace Tanks the industry choice. Only Ace tanks feature a custom-molded gasket in the lid. Manufactured from extruded Nitrile rubber, the gasket snaps into the lid and ensures a watertight seal. Our exclusive lid design locks in place with nylon ties, eliminating the need for metal fasteners that can corrode and fail.