What is the maximum distance the water table must remain from the ground surface year-round for certain leak detection methods to be applicable?

The maximum distance that the water table must remain from the ground surface year-round for certain leak detection methods to be applicable is 20 ft. This requirement is based on the technical considerations related to the effectiveness of various leak detection systems, which can be influenced by the proximity of the groundwater to the surface.

When the water table is within 20 ft of the surface, leak detection methods, especially those relying on groundwater monitoring, tend to remain reliable, as they can effectively detect small leaks and changes in liquid levels in the tank system. Monitoring systems that exceed this threshold may find it difficult to accurately assess potential leaks or may encounter issues with false readings due to interference from the surface environment or fluctuations in the groundwater level. Maintaining a closer relationship between the water table and the surface helps ensure that the detection systems work as intended, providing necessary oversight regarding potential environmental impacts from underground storage tanks.