The Chem-Tainer 90 Gallon HDPE Rectangular Open Top Tank is a straight-walled polyethylene vessel built for batching, mixing, washdown, and open-access water storage where you need to dip or manually fill a contained volume without fighting a domed lid. The open-top design and rectangular footprint make it easy to integrate into a bench, a secondary containment basin, or a row of staged tanks against a wall, and the molded polyethylene construction handles routine water service without corrosion or lining maintenance. As a rectangular open top tank in HDPE, it slots into the same open-tank roles operators search for, just with a flat-sided footprint instead of a round drum.
Will this tank work for your application?
This is a 90-gallon rectangular open top tank molded in polyethylene, and it ships as a bare vessel - there is no pre-installed outlet, bulkhead fitting, or gasket. You fill and draw from the top, or self-install your own bulkhead and gasket if you need a bottom outlet, so plan that hardware separately before you buy. Because the rim is the working surface, the 90-gallon rating is brim-full geometry: set your normal fill level below the top edge and budget freeboard for splash, mixing turbulence, and outdoor evaporation. Plan your support around a full load too - at 90 gallons of water this tank carries roughly 751 lb full, and a rectangular tank concentrates that weight along its base edges rather than spreading it across a round footprint, so confirm your pad, bench, or shelf is flat, level, and rated to hold that perimeter load continuously. If you are still deciding between this footprint and a closed vertical, run your volume through the Tank Sizing Calculator and the Tank Sizing Guide first, since an open rectangular tank trades headspace control for top-down access.
What to get right before you buy
The most common mistake on an open top tank is treating the rim as a sealed boundary. It is not - this tank vents to atmosphere by design, so it is suited to water and ambient-condition storage, not pressurized or sealed service. If your water source is dirty, hard, or aerated, the open top makes inspection and cleaning easy, but you will want a cover or screen against debris and insects. Freeze duty deserves extra thought here specifically: an open rectangular vessel has a large exposed surface and flat walls, and when water freezes it has nowhere to expand laterally, so the walls take the stress. The guides on fire-water reservoir design and freeze protection and industrial water reuse tank topology walk through grey-water, rainwater, and HVAC-condensate aggregation if this tank is pulling double duty.
Foundation and placement
Set this tank on a continuous, level surface that supports the full footprint - because a rectangular open top tank loads along its base edges, a properly sized pad keeps the walls true and prevents bowing under a full water column. Our guide on concrete pad sizing for above-ground polyethylene tanks covers the ACI framework if you are pouring a new pad. For long-term service, the way HDPE behaves at the vapor-saturated headspace is worth understanding even on an open vessel - see the breakdown of HDPE wall thickness at the headspace and where premature failures originate. Cross-check the molded dimensions against the technical drawing on this page before you frame a stand or pour a pad.
This tank ships LTL from Hummelstown, Pennsylvania, and freight is quoted live to your ZIP based on distance and destination type. Northeast and Mid-Atlantic buyers are close to that origin, which usually means a shorter LTL lane; if you are farther out, quote before you assume. Get your number in seconds with the Freight Cost Estimator, or call 866-418-1777 and we will confirm the nearest plant, lead time, and the best way to get a 90-gallon rectangular open top HDPE tank delivered to your site.
