Doorway Water Storage Tanks are a must if your entry space is roughly 30 inches. The perfect tank for many applications & industries, Doorway Water Tanks are great for Safe Potable Drinking Water Storage, Irrigation, Rainwater Collection, Fire Protection & more. Avail in 250-400 gallon sizes, these slimline water tanks are a great way to maximize your space. The width dimension of the Doorway Water Tanks allow them to fit through a conventional doorway. The design of these tanks allow them to be freestanding/self-supporting and eliminates the need for a steel frame.