A 1000 gallon low profile two compartment septic tank with the tees already in
The Norwesco 1000 gallon preplumbed two compartment septic tank, part number 42406, is a green polyethylene tank 127 inches long, 60 inches wide and 51 inches tall, weighing 377 lb empty. Preplumbed means the 4 inch adapters and PVC tee assemblies at the inlet and the outlet are installed at the factory, so the installer connects the pipes and backfills with nothing to fit in the hole. Two compartments split the tank into a first chamber where most solids settle and a second that polishes the effluent before it leaves for the drainfield. The low profile shape keeps the excavation shallow where rock, groundwater or a shallow sewer line rules out a deep hole. Access is through a 20 inch gasketed manway. Norwesco lists the tank as IAPMO approved, backs it with a 5 year warranty, and sets the service limit at 130 F. Norwesco lists state septic approvals for this model in Alaska, Arkansas, Colorado, Idaho, Kansas, Louisiana, Missouri, Montana, Nebraska, Oklahoma, Oregon, Texas and Washington.
Does your county accept this tank? Call 866-418-1777 with the county and we will check before you order, or get freight to your ZIP and add it to your cart above.
Why two compartments, and why preplumbed
The first compartment takes the raw flow and holds most of the solids; the second takes the settled liquid and gives any remaining solids a second chance to drop before the effluent leaves. That protects the drainfield, which is the expensive part of a septic system and the part that fails first when solids get through. Most of the states on the list above now require two compartments on a new install. Preplumbed suits the installer who wants the tank ready to connect: the tees are seated and oriented at the factory, nothing gets lost on site, and the inspector sees factory work at both ends. If the pipe runs are awkward and you would rather set the tees yourself, the low profile two compartment tank with loose plumbing and a side inlet is the same shell. Our note on single compartment versus two compartment septic tanks goes through the trade-offs, and Norwesco IAPMO and CSA septic tank approvals explains what the listings cover. The county health department issues the permit and sets the size for your bedroom count; call them with the part number before you order.
Openings and fittings
- Inlet. A 4 inch adapter with a PVC tee assembly, factory installed. The inlet tee turns the incoming flow downward so the scum layer in the first compartment stays undisturbed. The inlet sits higher than the outlet.
- Outlet. A 4 inch adapter with a PVC tee assembly, factory installed in the second compartment, drawing from below the scum and above the sludge. If your code calls for an effluent filter in the outlet tee, tell us and we will add one.
- Manway. A 20 inch gasketed manway. Both compartments need pumping, so plan access to each; if the lid will finish below grade, ask us for the riser that brings it to the surface.
- Drawing. Norwesco's drawing, linked under Technical Drawing on this page, gives the invert heights and the baffle position you need to set the pipe grades.
Setting it
Follow Norwesco's installation instructions for this tank: they set the bedding, the backfill material and the order in which you fill the tank with water while backfilling so the walls are loaded evenly from both sides. Never backfill an empty polyethylene septic tank, and never set one where vehicles will drive. Level the bedding on both axes before the tank goes in. Check that both factory tees are still seated square after the ride, connect the pipes, fill with water to the outlet, and then call for the inspection. The low profile tank field guide covers handling a long shallow tank on site.
Related tanks
Single compartment versions of the same low profile shell: the 1000 gallon low profile one compartment tank and the version with a side inlet. For Florida: the 900 gallon and 1050 gallon Florida two compartment tanks.
Shipping and receiving
The tank ships LTL, 127 by 60 by 51 inches and 377 lb, from Norwesco's Shawnee, Oklahoma or Washougal, Washington plant, whichever is nearer. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP, or request a written quote for the permit file. At the tailgate, check the part number against 42406 on the bill of lading, look at both installed tees and the manway lid, and walk the shell for transit damage before the driver leaves.
Questions before you order? Call 866-418-1777.
Freight and documents
Ships from: Shawnee, OK; Washougal, WA. LTL freight is quoted to your ZIP with the freight cost estimator or by phone at 866-418-1777. The listed price is before freight.
Technical drawing (PDF) for Norwesco 42406.
See this tank
Product video. Watch the Norwesco 1000 Gallon Plastic Preplumbed Two Compartment Septic Tank with Low Profile Design video (61 seconds) with dimensions, fittings and shipping notes.
Ready to order?
Add it to your cart at the top of this page, get LTL freight to your ZIP, request a written quote, or call 866-418-1777. The listed price is before freight.
