The Snyder Industries 35 Gallon Double Wall Tank gives you secondary containment in a compact 22-inch square footprint, with the inner tank captured inside an outer wall. It holds 35 gallons, stands 36 inches tall, and is molded in black High Density Linear Polyethylene rated to 1.9 specific gravity. The double-wall design means a leak in the primary tank is captured by the outer shell rather than reaching your floor or site, which is the whole reason to choose this configuration over a single-wall drum of the same volume.
Will it work for your application
Capacity is 35 gallons in a 22.0 x 22.0 inch footprint at 36 inches tall, so this double wall tank fits tight equipment pads, garages, and indoor wash-down areas where a wider tank won't go. Filled with water it carries about 292 pounds, and the tank is rated to a maximum contents weight of 555 pounds. Plumbing comes off a 6-inch threaded and vented fitting up top, and fill and inspection access is through a cap with a 4-1/2 inch opening. Those two openings are all the tank ships with, so before you order, confirm your inlet and vent hardware threads into the 6-inch vented bung and that your fill or pump hose clears the 4-1/2 inch access. The exact fitting positions and elevations are shown on the technical drawing on this page, so check your plumbing routing against it before you set the tank. If you are unsure whether 35 gallons matches your draw-down and refill cycle, the Tank Sizing Calculator and Tank Sizing Guide will help you size it.
Specific gravity and freeboard
The 1.9 specific gravity rating governs how much weight the wall can carry, not whether a given chemical is compatible with the resin or the gaskets — confirm chemical suitability separately before any service beyond water. The number that actually limits how much you can put in is freeboard, not raw capacity. On a double-wall HDPE tank the usable volume is less than the nameplate once you account for thermal expansion and the headspace the wall geometry requires. The mistake to avoid is filling to the brim on a heavy, dense liquid and assuming all 35 gallons is working volume. Snyder's Captor double-wall line is engineered to ASTM D1998, and our guide on Captor double-wall freeboard sizing per ASTM D1998 walks through the density and thermal math so you know the real draw-down volume you can actually use. If your liquid sits at the vapor-saturated headspace, the wall behavior there is worth understanding too — see HDPE tank wall thickness at the vapor-saturated headspace.
Sealing the threaded port
The 6-inch fitting is a threaded sealing connection, which makes the gasket or seal at that port the failure point on dense-liquid service rather than the tank wall. Confirm a gasket and seal material rated for whatever you are storing before you put the tank in service; the threaded bung itself only does its job if the seal behind it holds. For anything heavier than water, match the seal to the contents, not just the 6-inch thread size.
Freight
This 35 gallon HDPE double wall tank ships LTL from the Snyder plant in Marked Tree, Arkansas, the nearest plant that fulfills it. Freight is quoted live to your ZIP code rather than baked into the listed price, so use the Freight Cost Estimator to get a rate to your address, or call us at 866-418-1777 and we will quote it for you. Shipping from Marked Tree keeps transit short for the central and southern states, and the estimator will show you exactly what it runs to your location.
