How to Turn off Gas to Your Water Heater

Hot water heater maintenance
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There are several reasons why you might need to turn off the gas supply to your water heater. For example, if you are planning to replace a water heater, you will, of course, need to turn off the gas. But there is a more important and more urgent reason you may need to do this. 

If you smell gas in the vicinity of your water heater, or anywhere in the house, for that matter, then you must turn off the gas to the water heater immediately. The smell of gas alerts you of a potential gas leak that needs to be located and repaired. Left unattended, a gas leak could lead to an explosion and fire. Your first action is the turn off the gas to any appliances that use an open flame (a gas water heater is a principle one), and only then should you call the gas utility company and request that they come and locate the leak. Normally this is a free service, and you can count on utility service being there very, very quickly. The utilities understand the potential danger of gas leaks, and they are very diligent about addressing them. 

Remember that it is not just a gas leak in or around the water heater that prompts you to shut off the gas to the water heater. Any gas leak, anywhere in the house, could potentially be detonated by the open flame on your water heater. 

To turn off gas to the water heater follow these steps to make sure you do it safely.

  1. Move any items away from the water heater so you can access the gas pipe and shut-off valve.
  2. Locate the gas pipe that feeds gas into the water heater and find the shut-off valve. This is not the valve on the control box, but one that will be installed along the pipe run itself. The valve can have different appearances depending on who did the installation and when it was installed. Most plumbers will install a lever- or knob-operated shutoff valve that will be installed within a few feet of the water heater control box.
    NOTE: in rare instances, and particularly if the water heater has been installed by an amateur or is an older installation, the shutoff valve may not be present or may be located some distance from the water heater. Follow the gas pipe back from the water heater burner until you find the valve. In the event you find no shut-off valve at all, your only option will be to turn off the gas at the main gas meter. 
  3. Turn the handle of the shut-off valve 1/4" turn until it stops. When it is turned off, the handle will be at a 90-degree angle to the pathway of the pipe itself. 
  1. Check to make sure that the water heater has turned off. To do this, turn up the temperature setting on the control box, then peek inside the access hatch to make sure the burner is not ignited.
  2. Now call the gas company to investigate the source of the leak

If you still smell gas despite turning off the water heater, you should shut off the gas at the meter and call the gas company. While a faint odor is not a cause for panic, if the odor is strong, you and your family should leave the house completely until you get an all-clear from the gas company technician. 

  • Did you know: Natural gas itself has no odor. The "gas" smell that we are all familiar with comes about because the gas company places an additive into the gas mixture so that it can be smelled. So if you smell "gas," it is indeed a reason to call for help. That's why the smell is there. 

In most instances, the technician will find a fairly simple cause for the gas leak, such as a small leak in a connection between pipe segments or the connection where a flex tube is connected to the gas pipe. It may take only minutes for the problem to be remedied, as it may be as simple as tightening the nut connections.

An old standby technique for checking gas pipe joints for leaks is to coat the joints with a soap-and-water mixture and look for bubbles. These days, the technician will likely use an electronic sensing wand to check for the presence of gas around each joint and identify which one needs to be tightened or replaced.

The technician should relight the water heater for you after completing the repair. 

Water Heater Safety Tips

  • Keep the area around the water heater clear. Many people use water heater cossets and the top of the water heater for storage, but these areas should be kept clear. The water heater needs proper ventilation as a fire prevention measure. 
  • Never store combustibles such as paints or solvents on or near the water heater.