Our Precast Concrete Tanks are made at our NPCA certified facility. All our traffic rated septic and grease interceptor tanks meet the latest version of MT DEQ 4 - 2013. Our tanks are structurally engineered to HS-20 ratings and have bury depths that vary. Calculations are on file per request.  Traffic rated tank sizes are 1000, 1500, 2500, 4000 and 5000 gallons. Other sizes are are available per request.  Download our traffic rated tanks catalog for more details, PDF's and DWG's.