1000 Gallon Septic Tank / Pump Chamber – 1000 gallon septic tanks are suitable for 3 bedrooms, configured for gravity type drain fields, siphons or pump-out pressure dosing systems. Septic tanks are available in single compartment and two compartment configurations. These tanks are also commonly used as effluent dosing chambers on larger systems. Traffic rated drive-over lids and castings are available as an option along with concrete, PVC or fiberglass risers and lids.