I performed a comprehensive backflow prevention inspection today on multiple devices throughout the property. Following state-mandated testing procedures, I checked the operation of all backflow device components, including the relief valve, check valves, and shut-off valves. The backflow prevention testing revealed a failed first check valve in the main device, which I repaired by replacing the deteriorated rubber components and spring assembly. I documented all pressure readings before and after repairs, verified proper operation under various flow conditions, and submitted the required certification paperwork to the local water authority. I also identified and tagged all backflow devices on the property for future inspections.