Arrived to remedy a leak in the gas line close to the water heater. Performed a gas leak search and verified that the Union by the water heater is the only leak point. Spoke with homeowner about the repair. With homeowners approval removed the old union. Cleaned the threads on the existing gas line. Applied thread lube and installed the new union, sealing the gas system. Turned the gas back on to the water heater and bled the air out of the line. Performed another gas leak search. Fired up the water heater. System is safe and operating at this time.