The Norwesco 15000 Gallon HDPE Underground Liquid Storage Tank is a white polyethylene below-grade vessel for buried liquid storage at a scale where pouring concrete or trucking in a steel tank stops making sense. At 511 inches (about 42.6 feet) long, 101 inches (~8.4 feet) wide, and 107 inches (~8.9 feet) tall, this is a 42-foot underground tank, and the three questions that decide whether it is right for your site are whether it fits the job, what it costs to get it to you, and the one detail that trips people up on a buried tank this size.
Will it work for your site
This is a 15,000-gallon underground HDPE storage tank with a 101 x 511 inch footprint and a buried height of 107 inches. Norwesco lists the unit with a septic tank classification, so if you are putting it into a wastewater or septic application, confirm the specific approval that applies to your jurisdiction before you commit. Filled with water it carries roughly 125,100 pounds of liquid weight, so the excavation, bedding, and backfill have to be engineered to carry that load across the full 101-by-511-inch footprint - this is not a drop-in-a-hole tank. Use the Tank Sizing Calculator and the Tank Sizing Guide to confirm the capacity matches your draw and storage targets, and plan the trench length, access, and crane reach around a 42-foot vessel rather than guessing at clearances.
One install variable this listing does not pre-specify: fitting, manway, and riser configuration. On a 15,000-gallon buried tank the inlet, outlet, manway, and riser layout is the single biggest setup detail, so call 866-418-1777 to confirm inlet and outlet sizing, manway access, and gasket requirements before you order. Buyers searching for an underground septic or HDPE storage tank at this scale land here, and we would rather work those details with you up front than have you discover them after the hole is dug.
Know the limits before you fill it
No specific-gravity rating is published for this unit, so the 125,100-pound figure above is the weight of a full load of water - do not store any liquid heavier than water without confirming the rating with us by phone first. Beyond fill weight, the most common error on a large underground polyethylene tank is treating its wall and failure points like an above-ground tank. On buried HDPE vessels the demanding zone is the vapor-saturated headspace, not the liquid-filled lower wall, and liquid-side inspection routinely misses it; the guide on HDPE tank wall thickness at the vapor-saturated headspace walks through the ASTM D1998 sizing logic behind why these tanks are built the way they are. If your project crosses into Canada or sits under provincial wastewater rules, our guide on Norwesco IAPMO and CSA B66 septic tank approvals covers the cross-border scope versus US plumbing codes. For background on how engineered bearing surfaces are specified, the concrete pad sizing framework is useful reading on bedding and load distribution. Check the technical drawing on this page for the dimensional layout before you finalize your excavation plan.
Freight and how to order
This tank ships LTL freight from Norwesco's plant in St. Bonifacius, Minnesota, and at 42 feet it moves as freight quoted live to your ZIP code rather than at a flat published rate. Get your number with the Freight Cost Estimator, or call 866-418-1777 and we will work the delivery logistics, offload requirements, and lead time for a tank this large. We are glad to confirm site-fit, fitting, and burial questions before you order so the unit shows up ready to set.
