A 500 gallon one compartment septic tank that Norwesco lists as IAPMO approved
The Norwesco 500 gallon plastic one compartment septic tank, part number 41320, is a yellow polyethylene tank 101 inches long, 51 inches wide and 47 inches tall, weighing 172 lb empty. One compartment means a single settling chamber, the simplest septic tank there is, and 500 gallons is the small end of the range. It has a 20 inch gasketed manway on top to bring up to grade. Norwesco lists the tank as IAPMO approved and lists state septic approval for Alabama, Alaska, Georgia, Illinois, Minnesota, Montana, North Carolina, North Dakota, Oregon, South Carolina, South Dakota and Washington. The service limit is 130 F and Norwesco backs it with a 3 year warranty. 500 gallons of water weighs 4170 lb.
Is your state on the list? Call 866-418-1777 with the state and the burial depth and we confirm the approval and put the riser on the same order, or quote freight to your ZIP and add it to your cart above.
Where it goes
A 500 gallon septic tank serves a cabin, a seasonal cottage, a hunting camp, a shop with a toilet and a sink, or a dosing or trash tank step in a larger system. The health department sets the size from bedrooms and soil, and many jurisdictions require more than 500 gallons for a full time house, so confirm the size with them before you buy. If your state is not among the twelve Norwesco lists for this tank, call us; there is usually a sister tank that is approved where you are. The tank is built to be buried: the installer beds it on compacted granular fill and backfills in lifts while filling the tank with water in step, so the long sides are supported as the soil load goes on, and keeps vehicles off the area unless the installation is designed for traffic. Norwesco's installation instructions are the authority on bedding, backfill and burial depth; your installer follows them, not this page. At 172 lb empty, two people can set it by hand on a lot a machine cannot reach.
Openings, fittings and the riser
- Manway. A 20 inch gasketed manway: wide enough to pump out and inspect. The gasket keeps groundwater out and odour in. It comes up to grade through a riser; tell us the depth from the top of the tank to finished grade and we put the right riser on the order.
- Inlet and outlet. Norwesco's data for this tank lists no inlet or outlet fitting, so the tees and their gaskets are added to suit your permit. Tell us the pipe size from the house and we confirm what the tank ships with and what you add. Set the inlet higher than the outlet so flow is by gravity, and dry-fit everything before it is tightened, because once the tank is buried nothing moves again.
- Drawing. Norwesco's drawing for this tank, linked under Technical Drawing on this page, shows the manway position and the inlet and outlet heights.
One compartment or two
A single chamber settles solids and passes liquid; a two compartment tank adds a second settling stage and some jurisdictions require it. Our comparison of one compartment and two compartment septic tanks lays out when each is the right buy. The inspector will ask for the approval behind the tank; our note on Norwesco septic tank documentation, north and south of the border explains which document covers which jurisdiction. If you are sizing the whole system, the tank sizing calculator and tank sizing guide cover the storage side.
Sizes nearby
One size up in the same family is the 750 gallon one compartment septic tank. Call us if your permit calls for a size between them or a two compartment tank.
Shipping and receiving
The tank ships LTL freight, 101 by 51 by 47 inches on a pallet and 262 lb on the bill of lading, from the nearest of Norwesco's Griffin, Georgia, St. Bonifacius, Minnesota, Tooele, Utah and Washougal, Washington plants. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP. Two people or a forklift can take it off the truck. At the tailgate, check the part number against 41320, look along both long sides and the manway rim for transit damage, and fill it with water once above ground before it goes in the hole so any problem shows while you can still reach it.
Questions before you order? Call 866-418-1777.
Freight and documents
Ships from: Griffin, GA; St. Bonifacius, MN; 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 41320.
See this tank
Product video. Watch the Norwesco 500 Gallon Plastic One Compartment Septic Tank - IAPMO Certified video (59 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.
