The Snyder Industries 35 Gallon HDLPE Double Wall Dual Containment Storage Tank (SKU SII-1000112N45) is a true tank-within-a-tank: the inner tank holds 35 gallons in white high density linear polyethylene, and the integral outer wall is the secondary containment that catches the inner tank's contents if it ever leaks. At 36" tall on a compact 22" x 22" footprint, this double wall tank clears a standard 24"-wide doorway and pad cutout, so it fits in tight chemical rooms, on mixing skids, and inside SPCC-regulated areas where floor space is at a premium. It carries a 1.9 specific gravity rating, which is what distinguishes it from a same-capacity single-wall water tank: integral secondary containment plus the headroom to hold dense liquids, not just water.
Will it work for your application?
Size your pad and your pump from the weight numbers, not just the gallon count. Filled with water this containment tank weighs about 292 lbs; loaded to its maximum rated contents it carries up to 555 lbs total. That 555 lb ceiling is what the 1.9 specific gravity rating buys you: you can run liquids up to roughly 1.9 times the density of water and stay inside the wall's design load, so confirm your liquid's SG is no greater than 1.9 before you fill. The inner tank is served by a 6" threaded/vented top port and a cap with a 4-1/2" access opening, both shown on the technical drawing on this page. Plan your fill and venting through that single 6" port rather than two openings, and treat the 4-1/2" access as the maximum insertable diameter for a gauge, probe, or pump intake. Verify those connections against your plan before ordering, and run your numbers through our Tank Sizing Calculator and Tank Sizing Guide to confirm capacity and footprint against your space.
The mistake to avoid
The most common error on a dual containment storage tank this size is treating the outer wall as bonus capacity. It is not. The outer wall is secondary containment sized to hold the inner tank's volume in a failure, so never plumb into it, fill it, or stack a load on it. The second mistake is ignoring freeboard: the 35 gallon rating is the inner tank's nominal volume, and dense or thermally active liquids need headspace left at the top. Our guide on Snyder Captor double-wall freeboard sizing per ASTM D1998 walks through how density and thermal expansion cut into the volume you can actually use. If this tank is going into a regulated containment area, the Snyder Captor double-wall tanks for SPCC 40 CFR 112 compliance walkthrough covers how a double wall design fits a spill-prevention plan, and concrete pad sizing for above-ground polyethylene tanks covers the slab under it.
Freight and how to order
This storage tank ships LTL from the Snyder plant in Marked Tree, Arkansas, with stock also moving from Arkansas and Mississippi locations, and freight quoted live to your ZIP code. Because the outer shell adds size and weight over a single-wall tank of the same capacity, get a real freight number before you commit. Run your delivery ZIP through our Freight Cost Estimator for a live LTL quote, or call our team at 866-418-1777 to confirm fittings, sizing, and the best routing for your site.
