A 3525 gallon low profile underground tank for septic or water storage
The Norwesco 3525 gallon multi-use underground liquid storage tank, part number 44390, is a white polyethylene tank 211 inches long, 102 inches wide and 51 inches tall, weighing 1305 lb empty. Multi-use means Norwesco builds it for either job in the ground: a septic tank for a large property or a cistern for rainwater, well water or a fire reserve. At 51 inches tall it is the shallow option at this capacity; the volume comes from the length, so it suits a site with room for a long trench but not a deep hole. It has a 20 inch manway cover and one manhole to bring up to grade. Norwesco rates it for liquids up to 1.9 specific gravity, the service limit is 130 F, and Norwesco backs it with a 3 year limited warranty. Norwesco's state septic approval list for this tank names every state except Hawaii, plus the District of Columbia. 3525 gallons of water weighs 29398 lb.
Septic permit or water store? Call 866-418-1777 with the state and the burial depth and we check the approval and put the riser on the same order, or add it to your cart above with freight quoted to your ZIP.
Where it goes
As a septic tank, 3525 gallons serves a large house, a multi-unit building or a small commercial site; the health department sets the size from bedrooms, fixtures and soil, so confirm the number with them before you buy. As a cistern, it is a whole-house rainwater supply or a fire reserve. Either way it 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 for this tank are the authority on bedding, backfill and burial depth; your installer follows them, not this page. At 1305 lb and 211 inches long it goes in with an excavator and slings, not a skid steer. If it is a fire reserve, our guide to fire water reservoir tank design for rural and remote sites covers the sizing discipline and freeze protection.
Openings, fittings and risers
- Manway. A 20 inch manway cover on the single manhole: wide enough to pump out, inspect, and lower a pump and a float if the tank is holding water.
- Inlet and outlet. Norwesco's data for this tank lists no inlet or outlet fitting. For septic service the tees and gaskets are added to suit your permit; for water service it is bulkhead fittings where your lines run. Tell us which job it is doing and we confirm what the tank ships with and what you add.
- Riser. Norwesco's riser and extension options for this tank are ordered one per manhole, and this tank has one: a 6 inch extension (N-63832), a 15 inch extension (N-63833), a 24 inch extension (N-63834), a 23 inch riser with a 12 inch lid (N-63831) or a 36 inch riser with a 6 inch lid (N-63830). Measure from the top of the tank to finished grade and tell us the number.
- Drawing. Norwesco's drawing for this tank, linked under Technical Drawing on this page, shows the manhole position and the flat areas of wall that take the fittings.
Septic or water, not both
Decide before it goes in the ground. A tank that has been a septic tank is a septic tank for good; a tank that starts as a cistern can hold drinking water. The approvals paperwork an inspector asks for is covered in our note on Norwesco septic tank documentation, north and south of the border. For a cistern, use the tank sizing calculator and tank sizing guide to check the volume against your roof area or your draw.
Sizes nearby
One size down in the multi-use range is the 2650 gallon multi-use underground tank, a taller shell for a shorter hole. For water only, the next step up is the 5025 gallon underground cistern. Call us with the excavation you can dig and we will say which shell fits it.
Shipping and receiving
The tank ships as oversize freight, 211 by 102 by 51 inches and 1305 lb, from the nearest of Norwesco's Fairfield, Texas, Hanford, California and St. Bonifacius, Minnesota plants. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP, or send a quote request for a permit file. Have an excavator or a loader with slings ready; the driver will not unload it alone. At the tailgate, check the part number against 44390 on the bill of lading, look along both long sides and the manhole 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: Hanford, CA; St. Bonifacius, MN; Fairfield, TX. 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 44390.
See this tank
Product video. Watch the Norwesco 3525 Gallon Multi-Use Underground Liquid Storage Tank 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.
