The water heater shut-off valve is probably the most easily located of your important shut-off valves. The water heater shut-off valve is always on the main water line going into the water heater. This is typically on the right side of the heater’s location. Both tankless and tank water heaters will have one and sometimes more than one shut-off valve. The reason that the water heater shut-off valve is important is the propensity for them to be ignored and then start leaking. Waterfalls from the ceiling in the middle of the living room or rivers running out of the garage are not normal or preferred. You must be proactive in replacing water heaters that are above living areas. The shut-off valve, if needed, will only limit the damage and obviously can only be employed when someone is home and knows what to do. Older tank water heaters will likely have a multi-turn gate valve but they may not function properly, so be careful. If installed correctly, newer water heaters and most tankless water heaters will have quarter-turn ball valves and usually more than one. Please note that many of the larger houses in the North Texas area may have a recirculation pump and/or a dedicated recirculation line. This is important to note in case of an emergency or when work is performed, as this pump should also have its own separate shut-off valves. They will need to be turned off and the pump unplugged to stop the water flow.