Storage tanks have a finite lifetime, and they should be carefully inspected annually. Read Consulting has performed numerous storage tank failure analysis. Steel tank failures were caused by corrosion. PVC tanks failures were caused by UV degradation of the polymer. Attached are two representative photos of tank failures analyzed in the past. One failure was a 40,000 gallon water storage tank on the California coast. In this case, the bolts on the bottom of the tank corroded away and allowed failure from the pressure at the bottom of the tank. The photograph on the right is a photo of a pressure switch on a male pipe nipple that was screwed into PVC female threads. This is a photo after the repair. The original assembly failed under pressure as a result of UV degradation of the PVC. The cantilevered switch applied enough force to cause the pipe to crack and fail. This PVC failure occurred as a result of UV degradation and poor assembly design. Read consulting has also been involved with tank failure analysis of stored chemical storage tanks and fertilizer storage tanks.