The Norwesco 2650 Gallon Multi-Use Underground Liquid Storage Tank (SKU N-43771) is a white polyethylene tank rated to a 1.9 specific gravity and built for below-grade liquid storage and septic service. At 81 inches tall with a 99 x 155 inch footprint, it holds 2,650 gallons and is engineered for burial, where compacted backfill supports the tank wall under load. The standout spec here is that 1.9 rating: it is what lets this multi-use underground tank carry denser, heavier-than-water liquids that would under-rate a typical 1.5-rated water tank.
Will it work for your site?
On an underground tank the first question is contents weight and how the soil carries it, not just gallons. Filled with water, the tank holds roughly 22,101 pounds; at its full 1.9 specific gravity rating, rated contents reach about 41,992 pounds. That filled load sits over the 99 x 155 inch footprint, so the bedding and backfill under and around the tank have to support it uniformly - this is exactly why an underground polyethylene tank cannot be treated like an above-ground one. Plan your excavation in all three axes from the pack numbers: the 99 x 155 inch footprint is your hole-bottom dimension, and the 81-inch height is the vertical envelope that sets burial depth and cover. Check that 81-inch height against your inlet and outlet elevations before you dig. For capacity and dimensional planning, our Tank Sizing Calculator and Tank Sizing Guide walk through the numbers, and because this is a multi-use underground water store, it can also serve as emergency or fire-reserve storage - see our guide on fire-water reservoir tank design for rural and remote sites.
Underground and septic considerations
Classified as a septic tank, this Norwesco unit is a common choice for underground liquid storage and on-site septic applications. Septic approvals are jurisdiction-specific, so confirm that this model is accepted by your local health department or plumbing authority before purchasing for a septic install. For the regulatory picture on Norwesco's septic line, see our guide on Norwesco IAPMO and CSA B66 septic tank approvals, which covers cross-border scope and how those listings line up against US plumbing codes. The most common mistake on an underground tank is treating it like an above-ground tank: underground polyethylene is designed to be supported by compacted backfill, and skipping that step risks deformation under load.
Fittings and ordering
Fitting and gasket configuration is not specified in this listing's data, so confirm inlet and outlet size and grommet or gasket compatibility by phone before ordering, especially for the septic plumbing tie-in. Call us at 866-418-1777 and we will verify the plumbing details, confirm septic acceptability for your jurisdiction, and check lead time.
This tank ships LTL freight from the Norwesco plant in St. Bonifacius, Minnesota. Because it is a large underground storage tank, freight is quoted live to your ZIP code rather than carried at a flat rate - run your address through the Freight Cost Estimator for a freight estimate, or call 866-418-1777 and we will quote it for you. Tell us your install timeline and delivery access, and we will line up the right freight option for your underground tank or storage tank project.
