Low-profile one-piece septic tanks from Norwesco have molded-in support columns. These columns in the middle of the tank are filled with flowable soil before backfilling to maximize strength, stabilize the tank during backfill and reduce buoyancy. They have molded-in corner tie-down and lifting lugs for ease of handling and moving. The inlet and outlet holes are predrilled. Gaskets and field-adjustable sanitary tees that accept SDR 35 or Schedule 40 pipe are included. The installer can also use dual-wall pipe or PVC ribbed pipe for a riser. 800/328-3420; www.norwesco.com.