All Equinox Buriable Water Storage Tanks are manufactured from fiberglass on the same modular principle as the underground septic and holding tanks. Water storage tanks have a 1¼” (32) FIP bulkhead outlet fitting, 3” (76) ABS fill fitting, and 1½” (38) solvent weld fitting. These tanks are suitable for burial to a depth of up to 2’ (610). Recommended installation involves burying the tank with a 3” (76) layer of insulating styrofoam placed 6” (152) above the tank. Tanks buriable to a depth of 7’ (2135) are available. Contact factory for details.