The Snyder Industries 500 Gallon ASTM XLPE Double Wall Tank (SKU 5780102N42) is a fully contained double wall tank built for operators who need secondary containment without pouring a concrete berm. It holds 500 gallons in a compact 53" x 53" footprint and stands 81" tall, so the containment volume is engineered into the outer shell rather than the floor space around the tank. The tank is molded in Natural White crosslinked linear polyethylene (XLPE) with a 1.9 specific gravity structural rating, and it arrives with two distinct top openings: an 18" PE threaded and vented fitting, plus a separate manway with 15" access for entry and inspection.
Will it work for your site
Filled with water, this 500 gallon double wall tank carries roughly 4,170 lb of contents, and that ~4,170 lb figure is the load path that matters for water service. The 7,923 lb number you may see is the resin's structural rating at 1.9 specific gravity, not a fill target for water, so size your slab or pad to the real water load across the 53.0 x 53.0 inch footprint. At 81" tall on a 53" x 53" base, confirm door and gate clearance and overhead room before delivery, and remember the fill port sits above the 81" tank height. If you are still deciding between capacities, run your numbers through the Tank Sizing Calculator or read the Tank Sizing Guide first.
What the double wall actually buys you
The value of a Snyder double wall design is the interstitial space between the inner and outer shells, which captures a leak from the primary tank instead of letting it reach the ground. Sizing that freeboard correctly matters, especially if you ever run a heavier fluid or see thermal expansion in outdoor service. Our guide on double-wall freeboard sizing per ASTM D1998 walks through the real usable volume, and if this is going into a rural fire-water or reservoir role, the fire-water reservoir design guide covers NFPA 22 sizing and freeze protection.
The mistake to avoid
The most common error on a double wall tank is treating the outer shell as usable storage or defeating the vent. Venting happens through the 18" PE threaded/vented fitting; the 15" manway is the inspection and cleanout access, not the vent. Keep the 18" fitting vented as supplied so the tank does not draw a vacuum on discharge or pressurize on fill, and never substitute a sealed replacement lid on that port. Also plan your load path around the ~4,170 lb water figure rather than the resin's structural rating. See the technical drawing on this page for exact fitting locations and elevations before you plumb the tank.
This tank ships LTL freight from Snyder's plant in Marked Tree, Arkansas, quoted live to your ZIP. Get an exact number with our Freight Cost Estimator, or call 866-418-1777 and we will quote it for you. We can also match bulkhead fittings and gaskets sized to the 18" threaded port and the 15" manway, and confirm sizing on this 500 gallon XLPE double wall tank before your order goes out.
