The Norwesco 2500 Gallon Multi-Use Underground Liquid Storage Tank (SKU N-44079) is a buried polyethylene vessel built for underground liquid storage and septic service. It holds 2,500 gallons in a low-profile horizontal body measuring 51 in. high, 99 in. wide, and 159 in. long, giving a 99.0 x 159.0 in. footprint that drops into a single excavation. Molded from polyethylene with a 1.9 specific gravity rating, it carries dense liquids well past the weight of plain water, which is what makes it work as both an underground storage tank and a septic tank.
Will it work for your install?
Full of water (SG 1.0), this tank carries about 20,850 lb of contents; at its 1.9 SG rating the maximum rated contents weight climbs to 39,615 lb. That spread matters underground: the rating tells you the tank wall and structure are validated for liquids heavier than water, but your bedding, backfill, and burial depth still have to support the loaded weight you actually plan to store. Before you commit, confirm your septic or non-potable storage application against local plumbing and on-site wastewater code, since whether a poly tank is accepted varies by jurisdiction. Use the Tank Sizing Calculator and the Tank Sizing Guide to verify 2,500 gallons fits your daily demand or reserve target before you dig. The same body also serves rural and remote sites as a buried fire-water reservoir; our guide on fire-water reservoir design and NFPA 22 sizing covers private fire-protection reserves and cold-climate freeze protection.
The mistake to avoid
The number that trips people up on a buried tank is the burial and backfill spec, not the headline gallons. This is an underground tank with a 1.9 SG rating, so it is rated for heavier-than-water contents, but underground polyethylene tanks are sensitive to installation: correct bedding material, even backfill, and the manufacturer's burial-depth limits all govern whether the tank performs as rated. Read the technical drawing on this page for the overall dimensional layout. Because inlet and outlet fitting details are not published in this listing, confirm the inlet/outlet size, grommet or gasket type, and any bulkhead fittings by phone before ordering, so your on-site wastewater plumbing connections match local code. Norwesco septic approvals also vary by jurisdiction; our guide on Norwesco IAPMO and CSA B66 septic tank approvals walks through how those listings map to US plumbing codes and Canadian cross-border scope.
Freight and ordering
This Norwesco underground tank ships LTL freight, quoted live to your ZIP. It ships from the nearest Norwesco plant of Hanford, CA, Shawnee, OK, or St. Bonifacius, MN, so your freight cost depends on which of those three is closest. Buyers in California, Oklahoma, or the Upper Midwest near St. Bonifacius, MN typically draw a materially shorter LTL lane, which is worth checking before you order. Get a real number with our Freight Cost Estimator, or call 866-418-1777 to confirm fittings and lock in your underground septic or storage tank order.
