What is one of the most common causes of UST leaks?

Corrosion of underground tank walls and fittings is indeed one of the most common causes of leaks in underground storage tanks (USTs). Over time, the metal components of a tank can degrade due to environmental factors, such as moisture in the soil, chemicals in the fuel, and the natural processes that affect metals. This degradation can create holes or weaknesses in the tank structure, leading to leaks.

Corrosion can be exacerbated by several factors, including the type of fuel being stored and the soil conditions surrounding the tank. For example, if a tank is not properly coated or if it is made of materials that are susceptible to corrosion, the likelihood of developing leaks increases significantly. Regular inspections and monitoring for corrosion are critical in the maintenance of USTs, which helps prevent leaks that can lead to environmental contamination and regulatory issues.

The other options are important in the context of UST maintenance, but none directly represent as common a cause of leaks as corrosion does. Overfilling tanks is a risk, but it typically results in spills rather than leaks from the tank structure. Failure to monitor fuel levels can lead to operational issues but does not directly contribute to structural leaks. Use of improper materials may also lead to issues, but competent materials and methods are typically employed