Underground fiberglass tank warranties are typically good for 1 year. This includes wastewater, fire protection, rainwater collection and storm water suppression tanks. The exception is the 30 year warranty for a NSF potable water tank. The corrosion barrier on all these tanks are manufactured very similar. However, the potable water tank has an interior NSF listed vinyl ester resin. A Xerxes potable water tank is one of the only tanks manufacturers that provides a NSF Listed potable water tank. Most of their competition merely builds tanks to NSF standards. To download the warranty visit our library.