Most home improvements stores, including The Home Depot, Lowe's, Menards and Ace Hardware, sell some type of small water tank. As of October 2015, only Menards offers simple, small water storage tanks for sale with 300- and 500-gallon sizes available.
The Home Depot, Lowe's and Ace Hardware carry a wide selection of pressurized water tanks, including models with a 2-gallon capacity. Rain barrel water storage systems are also offered for sale by all four retailers, ranging from 30 to 100 gallon sizes in a variety of shapes, designs and capacities. Inventory varies by location and can be checked online by ZIP code.