ABOVE-GROUND WATER STORAGE TANKS All aboveground polyethylene rainwater storage tanks are manufactured using resins that meet FDA specifications to ensure safe storage of potable water. The black or dark green color limits light penetration which reduces the growth of water-borne algae. All RMS rainwater storage tanks are shipped with the appropriate fittings necessary to connect your rainwater harvesting components. RMS aboveground rainwater storage tanks range in size from 200 gallons to 12,000 gallons. RMS offers a full range of corrugated, galvanized rainwater storage tanks. These tanks are constructed of Scafco corrugated, galvanized, punched and rolled steel wall sheets that are bolted together at a project site. Most tanks are round structures and range from 6' to 105' diameter. Corrugated rainwater storage tanks generally are fitted with preliners and flexible membrane liners on the inside of the tanks for water containment. The tanks do not have a bottom structure that requires them to be erected on site on a concrete slab. The use of a flexible membrane liner also distributes the water load uniformly across the foundation area. Storage capacity ranges from 600 gallons to 440,000 gallons. RMS has tank sizing software to assist you in sizing your rainwater storage tank. If you would like assistance sizing your rainwater storage tank please fill out our tank sizing request form.