Methods and systems for determining a possible leak within a gas water heater. One system is a gas water heater including a blower and an electronic processor. The electronic processor is configured to activate the blower for a predetermined amount of time, receive, during the predetermined amount of time, a measurement of a characteristic of the blower, perform a comparison between the measurement and a predetermined characteristic threshold, and determine, based on the comparison, that a blockage is present within the water heater. The electronic processor is further configured to output a notification in response to determining the blockage is present.