The 550 Gallon HDPE Vertical Liquid Storage Tank from Snyder Industries (SKU SII-1800400N51) is a black, high-density polyethylene vertical storage tank built for above-ground liquid storage where a stable, high-capacity footprint matters. It stands 75 inches tall on a 48 x 48 inch base, holds a rated 550 gallons, and carries a 1.9 specific gravity rating. That SG number is the one to anchor on: the tank wall is engineered to hold contents substantially heavier than water, which is why this vertical tank covers a range of storage duties beyond plain water.
Will it work for your site?
Filled with water, this tank carries roughly 4,587 pounds. Its 1.9 SG rating means the wall is built to carry up to about 8,715 pounds of contents - roughly a 4,100 pound margin over plain water - so the same tank handles denser liquids up to 1.9 specific gravity without stepping up to a different vessel. That headroom is the built-in flexibility here; match the tank to your stored liquid and its actual specific gravity. A 48 x 48 inch footprint concentrates that load, so a properly sized, level concrete pad is not optional. Our concrete pad sizing guide walks through the ACI 360R-10 framework for above-ground polyethylene tanks, and the Tank Sizing Calculator and Tank Sizing Guide help you confirm 550 gallons is the right volume before you commit. If you are sizing for rural fire protection or a private reservoir, the fire-water reservoir design guide covers NFPA 22 sizing discipline.
Fittings and access
This tank is configured with an 18-inch PE threaded/vented manway lid providing a 15-inch clear access opening for interior entry, inspection, and cleaning, plus a flange fitting. Fitting positions and sizes are shown on the technical drawing on this page, so cross-check outlet heights and thread sizes against your plumbing plan before you order valves or bulkhead adapters. The pack lists no supplied gaskets or fitting seal material, so verify that any bulkhead gasket or o-ring you add is chemically compatible with your stored liquid - that seal material is buyer-specified.
The mistake to avoid
Do not read a 1.9 SG-rated vertical tank as a food-grade or potable-certified vessel - this pack specifies neither, so match the tank to your actual stored liquid and never assume a certification the spec does not state. As HDPE tanks age, wall thinning tends to originate at the vapor-saturated headspace rather than the liquid-wetted lower wall, which is exactly where routine liquid-side inspections miss it; the HDPE wall-thickness guide explains the ASTM D1998 sizing logic behind it. For a full walkthrough of this size class, see our 550 gallon vertical tank buyer's guide.
This tank ships LTL freight from the Snyder plant in Chowchilla, California, with the exact cost quoted live to your ZIP code. It arrives empty, so it is light to place and no forklift is needed to receive it - but the pad underneath must carry up to 8,715 pounds when the tank is full and rated, which makes a level, load-rated base the critical prep step. Because a 75-inch vertical storage tank is a bulky LTL shipment, confirm you have equipment or enough hands to offload before the truck arrives. Run your address through the Freight Cost Estimator for a freight quote, or call 866-418-1777 and we will handle it.
