Rotationally molded polyethylene septic tanks from Coon Manufacturing have a 1/2-inch wall thickness with a rectangular design that has vertical ribs every 3 inches for added strength. They are available in 500-, 1,000- and 1,500-gallon sizes. The 1,000- and 1,500-gallon units can be a single- or double-compartment tank. When installed properly and kept away from areas with motorized traffic, they can provide years of service. Tanks are sold with tees, grommets and lids included, and predrilled inlet and outlet holes for use with Schedule 40 pipe can be provided free of charge. Risers are also available. 660/485-6299; www.coonmfginc.com.