California ICC UST Inspector Practice Exam

Which method is an approved quantitative method of non-visual monitoring for existing UST systems?

1. Ground Water Monitoring

2. Vadose Zone Monitoring

3. Statistical Inventory Reconciliation

4. Interstitial sensor

The correct answer is: Statistical Inventory Reconciliation

Statistical Inventory Reconciliation is an accepted quantitative method of non-visual monitoring for existing underground storage tank (UST) systems. This method involves the comparison of the physical inventory of tank contents with the measured or estimated amount of product that has been dispensed during a certain period. It utilizes statistical analysis to assess discrepancies and determine if there is a leak present in the tank system. The effectiveness of Statistical Inventory Reconciliation lies in its ability to quantify any losses or discrepancies through statistical techniques, allowing for the reliable detection of leaks without requiring direct visual inspections of the tank or the surrounding environment. This is crucial because leaks can lead to environmental contamination and must be detected early to mitigate risks. Other methods, such as Ground Water Monitoring and Vadose Zone Monitoring, involve examining the conditions of the surrounding soil or groundwater but may not provide quantitative data as directly as statistical methods do. Interstitial sensors, while useful for detecting leaks, rely primarily on physical sensors and not on statistical analysis of inventory data. Hence, Statistical Inventory Reconciliation stands out as the most effective quantitative method in this context.