A 1000 gallon two compartment septic tank in yellow, accepted in most states
The Norwesco 1000 gallon two compartment septic tank, part number 41720, is a yellow polyethylene tank 102 inches long, 60 inches wide and 63 inches tall, weighing 338 lb empty. It is the standard depth shell for a site where the sewer line leaves the house at normal depth and the dig is straightforward. 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; that split is now required by most states for a new install, which is why this tank carries one of the longest state approval lists Norwesco publishes. It ships with 4 inch adapters and PVC tee assemblies for the inlet and the outlet, and access is through a 20 inch gasketed manway. Norwesco lists the tank as IAPMO approved, backs it with a 3 year warranty, and sets the service limit at 130 F.
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.
Where it is accepted
Norwesco lists state septic approvals for this model in AL, AK, AZ, AR, CA, CO, CT, DE, DC, GA, ID, IN, KS, KY, LA, ME, MD, MI, MN, MS, MO, MT, NE, NV, NH, NM, NY, NC, ND, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI and WY. A state listing is the start, not the end: the county health department issues the permit, sets the tank size for your bedroom count and decides whether an effluent filter or a riser is required. Call them with the part number before you order and we will send any documentation they ask for. Our note on Norwesco IAPMO and CSA septic tank approvals explains what the listings cover, and single compartment versus two compartment septic tanks explains why the second chamber protects the drainfield, which is the expensive part of the system and the part that fails first when solids get through.
Openings and fittings
- Inlet. A 4 inch adapter with a PVC tee assembly. 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, which keeps the tank flowing in one direction.
- Outlet. A 4 inch adapter with a PVC tee assembly 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 to the order.
- 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 from the house and to the drainfield.
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; an out-of-level tank puts the outlet invert in the wrong place relative to the inlet. Fit the tees, connect the pipes, fill with water to the outlet, and then call for the inspection. Yellow makes the tank easy to see in an open hole and easy to find again if the lid is ever lost under turf.
Sizes nearby
Single compartment versions of the same shell: the 1000 gallon one compartment septic tank, part number 41718, the part number 44473 version and the 1000 gallon septic tank, part number 41721. One size down: the 750 gallon one compartment septic tank. One size up: the 1250 gallon one compartment septic tank. Our sizing guide by application covers where each size fits.
Shipping and receiving
The tank ships LTL, 102 by 60 by 63 inches and 338 lb, from the nearest of Norwesco's Griffin, Georgia, Lancaster, Ohio, Owego, New York, Shawnee, Oklahoma, St. Bonifacius, Minnesota, Tooele, Utah or Washougal, Washington plants. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP. At the tailgate, check the part number against 41720 on the bill of lading, count the adapters, 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: Griffin, GA; St. Bonifacius, MN; Owego, NY; Lancaster, OH; Shawnee, OK; Tooele, UT; 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 41720.
See this tank
Product video. Watch the Norwesco 1000 Gallon Plastic Two Compartment Septic Tank - IAPMO Certified video (71 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.
