Above-ground tanks larger than 10,000 gallons require dikes. If you can t afford a new tank, or if you re planning on taking the tank out of service within 10 years, a retrofit may be a better choice for your district. To retrofit a tank, you must protect it from corrosion, provide a leak detection system, and install an overfill alarm or prevention device. Tanks and piping both require corrosion protection. Steel tanks and piping can be cathodically protected.
Cathodic protection uses either sacrificial anodes or impress current to prevent electrolysis.
In simple terms, these systems create a positive electrical charge that prevents negatively charged metal ions from migrating from the steel tank into the earth around it, compromising the strength of the tank walls. Alternatively, steel tanks can be protected by coating the tank with a thick layer of noncorrodible material. If your tanks and piping are made totally of a noncorrodible material, such as fiberglass-reinforced plastic, they will meet the corrosion regulations. However, any metal piping connected to noncorrodible tanks still requires corrosion protection. In addition, underground storagetanks must be checked for leaks at least once a month.