Polyethylene water tanks are among the most durable rainwater storage solutions around. Seamless construction and high UV protection make polyethylene plastic tanks ideal for both above-ground and below-ground storage needs. RMS has poly water tanks for sale that will suit any capacity. For small residential projects, see our 305-gallon poly storage tank, while larger commercial applications will be interested in our 12,000-gallon poly tanks. Get the best in poly water tanks from Rainwater Management Solutions.