The gas company turned off gas at a home due to a minor gas leak. We knew that the city inspector would inspect the entire property before the gas could be turned back on, so the plumber checked the whole house and made other repairs in preparation for the city inspection. The property failed the inspection for several reasons, one of which was that there was not a cap on the rooftop water heater vent. Should a licensed plumber have known that this vent cap would be required for a city inspection?