The Norwesco 1250 Gallon Two Compartment Septic Tank is an IAPMO-certified polyethylene tank built for residential and light-commercial septic systems that need primary settling and a secondary clarification chamber in one body. At 1250 gallons, it measures 116 inches long, 55 inches wide, and 70 inches tall, with a 55.0 x 116.0-inch footprint to plan your excavation around. The shell is molded polyethylene in yellow.
What it does and how to size the dig
This is a two-compartment design, which separates the heavier solids settling in the first chamber from the clarified effluent moving toward the secondary chamber and the outlet. If you are weighing a single versus a two-compartment layout for your system, our guide on single compartment vs two compartment septic tanks walks through where each one fits. Use the dimensions above with the Tank Sizing Calculator and the Tank Sizing Guide to confirm capacity and verify the excavation clears the 70-inch height plus your cover depth. Match your inlet and outlet pipe, grommets, and gaskets to the sizes shown on the technical drawing on this page before you order any fittings.
Plan for the filled weight
Full of water, this tank weighs approximately 10,425 pounds. That number drives your set: the bed has to be level and properly bedded so the loaded tank does not settle unevenly, and your equipment has to handle the weight at the hole. The empty tank ships far lighter, so do not confuse this filled figure with the freight weight - your quote reflects the shipping weight, not the water-filled load. Confirm your site access and the path from the truck to the excavation before delivery day, because a 116-inch tank at over five tons full leaves no room for guesswork on the approach.
The certification mistake to avoid
The single biggest error with a Norwesco septic tank is assuming the IAPMO certification automatically satisfies your local inspector. IAPMO is a recognized septic approval, but Canadian installs and certain provinces look for CSA B66, and US jurisdictions vary in what they accept - our breakdown of Norwesco IAPMO and CSA B66 septic tank approvals covers the cross-border scope versus US plumbing codes. Confirm with your local code official that an IAPMO-certified Norwesco septic tank is accepted in your jurisdiction before you order. See the technical drawing on this page for inlet, outlet, and compartment layout when you submit your permit.
This tank ships LTL freight from the nearest Norwesco plant - Lancaster, OH, Owego, NY, or Washougal, WA - with the rate quoted live to your ZIP. Get your number with the Freight Cost Estimator, or call us at 866-418-1777 and we will line up the septic tank freight and answer any sizing questions.
