Norwesco 1500 Gallon Plastic Two Compartment Septic Tank - IAPMO Certified

Why two compartments

At 1500 gallons this is the septic size for a larger house in most codes. In a single chamber tank, solids settle and scum floats in the same space the outlet draws from, and a surge from a washing machine can push solids toward the drainfield. A two compartment tank takes the raw flow in the first chamber, lets most of the solids drop there, and passes calmer water into the second chamber before it reaches the outlet tee. The drainfield lasts longer for it. Our comparison of single compartment and two compartment septic tanks walks through when a code requires the second chamber and when it is simply the better choice. On approvals, Norwesco's IAPMO listing and the five state approvals are what the inspector will ask to see; our note on Norwesco IAPMO and CSA B66 septic tank approvals explains what each covers. For another state, call us; Norwesco sells the same two compartment tank under other part numbers with other approvals.

Openings and fittings

1. Inlet and outlet. A 4 inch gasketed PVC tee assembly at each end, ready for 4 inch drain pipe. The inlet tee drops the flow below the scum layer; the outlet tee draws from below it. Both go in before the system is used.
2. Manway. A 20 inch gasketed manway with a 20 inch lid. Below grade the gasket keeps groundwater out and septic gas in. Ask us about risers if the tank will sit deep enough that the lid needs bringing up to grade, and tell us if your code calls for access over each compartment.
3. Drawing. Norwesco's drawing for this tank, linked under Technical Drawing on this page, shows the baffle wall position, the invert heights of the inlet and outlet and the manway layout. Hand it to the installer with the permit.

Sizes nearby

At the same capacity, the 1500 gallon two compartment septic tank 41760 is this tank built at other plants with other state approvals, and the 1500 gallon one compartment septic tank with two manholes and the 1500 gallon Norwesco septic tank 41761 are the single chamber versions. One size down is the 1250 gallon one compartment septic tank. For water rather than waste, the 2000 gallon underground cistern tank is the buried storage tank. The tank sizing calculator and tank sizing guide cover sizing by bedrooms and daily flow.

Shipping, receiving and setting

The tank ships LTL from Norwesco's Hanford, California plant, 135 by 55 by 70 inches on the truck at 480 lb; for Hawaii, call us and we will quote the ocean leg. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP. Have a machine to lift it. At the tailgate, check 44481 on the bill of lading against the moulded number, look at both tee assemblies and the manway gasket, and walk the shell before you sign. Set it on the bedding Norwesco's installation instructions call for, and fill both compartments with water as you backfill so the walls and the baffle stay in shape; 1500 gallons of water weighs 12510 lb, and that water is what holds the tank round while the backfill goes in. Keep vehicles off the ground above it.

Questions before you order? Call 866-418-1777 with the permit in hand.