If equipped with an Automatic Tank Gauge (ATG), how often should it be programmed to test the tank?

The correct choice indicates that the Automatic Tank Gauge (ATG) should be programmed to test the tank at least monthly. Regular monthly testing is critical for maintaining compliance, ensuring safety, and minimizing the risk of leaks. Federal and state regulations often require that ATGs be set up to perform tests at this frequency to effectively monitor tank levels and detect any issues such as leaks in a timely manner. Monthly testing helps in maintaining the integrity of the storage system and provides a consistent assurance of the tank's performance and safety.

The other options suggest testing frequencies that are either too infrequent or do not meet the regulatory requirements many facilities must adhere to. For instance, weekly testing might be unnecessarily frequent for many operations, potentially leading to data overload without significant benefits. Testing every six months or annually could leave a facility vulnerable to undetected leaks or issues that could arise in between testing periods, which goes against the best practices for proactive leak detection and operational monitoring.