Talk to Water and Wastewater Equipment Company first when you’re shopping for storage tanks. Whether it’s a plastic tank (polyethylene) or fiberglass tank you need, we carry capacities from 45 gallons to 47,000 gallons. Bottom styles are flat, coned, or dish-shaped. Tops are open, closed, or dome-shaped. If you need a custom-fabricated storage tank, we can make one with flanges, manholes, and even mixer bridges. You install or we do it for you– the choice is yours.