Water heaters are in nearly every home and business in every community. They are usually unseen and rarely thought about unless there’s an issue. While reliable and safe, it’s important to understand hazards related to water heaters.

Pressure Relief Valve
Pressure relief valves are designed to prevent tanks from exploding if temperature or pressure exceeds the design capacity of the water heater. Remember to test the pressure relief valve periodically to ensure it operates as intended by pulling up on the handle to ensure water flows freely from the valve. The water should stop flowing once the handle is released. The water will likely be very hot, so be careful to not get burned. If the water does not flow, or only drips, the valve may need to be replaced or repaired.

Water Heater Drain Valve
Periodically flush your water heater of sediment that can collect at the bottom. You can do this by opening the drain valve usually located around six inches from the bottom of the unit. The water may be hot so avoid contact and burns. The water should drain into a drain or collection container and you may need to attach a hose to route the water to a suitable location. Sediment should be flushed until the water runs clear.

Temperature Control
You can usually adjust hot water heaters for various temperatures. The temperature should be at least 120o F to kill or destroy many common types of pathogens. The hotter the temperature, however, the less time before scalding occurs. Measure the temperature at the tap with a thermometer.

Temperature Time to Produce Serious Burn
120 degrees More than 5 minutes
125 degrees 1.5 to 2 minutes
130 degrees About 30 seconds
135 degrees About 10 seconds
140 degrees Less than 5 seconds
145 degrees Less than 3 seconds
150 degrees About 1.5 seconds
155 degrees About 1 second

(Rheem Commercial Gas Water Heaters, 2019)

Hazardous Energy Isolation
Hot water heaters usually run on natural gas or electricity. Both natural gas and electricity must be isolated prior to performing maintenance on any water heater. Electrical power should be disconnected, and lockout/tagout should be performed. Gas supply lines should also be shut off and locked/tagged out.

Put proper ventilation in place as recommended by the manufacturer. Improper venting can reduce your hot water heater’s efficiency causing a buildup of carbon monoxide. In extreme circumstances, oxygen from the surrounding areas can be reduced due to the combustion process. Ensure that:

  • Venting is accomplished as per manufacturer requirements
  • The vent is the same diameter as the tank's draft diverter
  • The vent goes straight up and out, without any dips
  • Proper earthquake proofing is accomplished, if applicable

Earthquake Straps
Water heaters can be damaged or tipped over in the event of an earthquake. Using straps to secure your water heater will reduce the likelihood of damage during an earthquake. Gas heater supply lines can be damaged, which can lead to a potential explosion.

Additional Water Heater Safety Tips
Keep safe by following these water heater recommendations:

  • Do not store combustible or flammable materials near a water heater. Maintain at least three feet from the ignition source to any combustible materials (National Fire Protection Association, 2011).
  • Extinguish the pilot light if using flammable liquids or aerosol sprays in the area.
  • If the device is in a garage, raise it so the pilot light is 18 inches above the floor. This helps prevent ignition of gasoline vapors that collect near the floor.
  • Consider installing an automatic gas-shutoff valve to stop the flow of gas if the ground moves or if gas flow increases dramatically. The valve prevents fires when a gas line breaks due to flood, earthquake, or other disaster.
  • Do not use pipe wrap or any other insulation within six inches of the draft hood or flue exhaust vent at the top of the natural gas water heater (Nationwide, 2019).

Above all, be sure to always follow the manufacturer recommendations, which is usually contained in the hot water heater’s owner’s manual.