Water Heater Safety Tips and How to Prevent Burns, Gas Leak and Explosion

What you should know about water heater safety. How to increase safety, protect the unit and your household. Learn how to prevent scalding burns, fire, gas leaks, carbon monoxide poisoning, and explosion.

The water heater owner's manual is the place where you should start collecting info about safety. The manual provides much information about the unit, venting, hot water, water heating safety tips, and what you should know about the correct and safe installation and operation.

For reliable water heating and peace of mind, the recommendation is to have a heater installed by the qualified technician or a plumber. If installing a heater by yourself, read the manual and follow the directions carefully.

The article about water heater safety focuses on potentially dangerous problems and components that need to be checked. The following problems are often the real causes of the heater's malfunction, property damage, and body injuries.

Water heater installation and location tips

Gas water heater

The location of the water heater is vital for its reliable and safe operation. The area should have unobstructed airflow and water drainage.

The room where the unit is installed must be free of corrosive elements and chemical compounds such as bleach, chlorine, hydrocarbons, or chemicals used in beauty shops, swimming pools, or cleaning. The problem is when these chemicals burn, they become very corrosive and dangerous for people, and harmful for the heater's elements. 

Install a water heater in a safe place and consider the following:

  • Do not install a gas water heater on the carpet.
  • If the gas heater is installed in a garage, make sure that the pilot light is at least 18" above the floor, therefore preventing ignition of the fumes collected near the floor.
  • Do not operate if the unit was flood damaged. The heater must be replaced.
  • Maintain required clearances to combustibles.
  • Do not operate the unit if soot is present.
  • Do not run an electric water heater if the tank is not full of water.
  • Expansion vessels should be installed in the closed systems.
  • Install an automatic gas shutoff valve to prevent potential leak due to earthquake or increase of gas pressure.

Venting tips

If you are installing a gas water heater, it is essential to install it in an appropriately vented room, so the unit can have sufficient air for gas combustion and vent the gases out safely.

By merely observing the burner flame you can say if your gas unit is getting enough fresh air or if there is a problem while gases are transferred out. 

A typical healthy flame has a light blue glow with a yellow tip. If the flame is yellow, the gas supply contains some pollutants, or the unit lacks sufficient air supply. If the flame is red, there is too much oxygen coming in.

Gasoline and other flammable materials and vapors located close to the heater are very dangerous. To prevent the accidental fire outside the heater from such vapors, today's gas heaters are designed with flammable vapor ignition resistance or FVIR. Check the manual and labels found on the heating unit for detailed instructions.

Every gas heater, either power vent or atmospheric vent, has to vent the products of combustion out. If the venting system is not set according to the instructions and codes, it might result in unsafe operation and carbon monoxide poisoning. This is why when running the atmospherically vented unit, it is recommended to provide sufficient airflow because the heater uses the inside air for gas combustion.

To maintain proper ventilation, check the following:

  • Check that the vent size is per instructions. The vent diameter should be the same diameter as the draft diverter. Do not exceed the maximum recommended length.
  • Ensure the proper vent slope.
  • The number of bends should not exceed the recommended number.
  • There are no dips and sags and any changes in the vent size.

The recommendation is to inspect the flue vent once a year, and look for the breaks, gaps, restrictions, obstructions and clean the dust and dirt.

Note: Buy and install a carbon monoxide detector so it can detect gas fumes before it becomes dangerous.

How safely to deal with natural and propane gas

Gas leaks are dangerous.

Always look and smell for gas leaks before lighting the pilot light on the gas water heater. The recommendation is to use the soapy water solution on all gas fittings and connections, and if bubbles appear, the gas leaks there.

Propane gas is heavier than the air, so it collects close to the floor, while the natural gas is lighter. This is why, for your safety, a propane water heater should not be installed in the basement.

You cannot see any of these two gases, but they have a specific smell as the odorant is added to help gas detection. So, remember to sniff near the floor if using the propane water heater and suspect the leak. Using the soap/water solution is the easiest way when checking the gas leak, but more than one method is always better, so using the gas detector is a good idea for your safety.

What to do if natural gas or LP gas is present?

  • Do not light the pilot on the water heater or any other appliance.
  • Do not use the electrical switch.
  • Do not use a phone in your home.
  • Leave the house, open the doors and call a qualified person and the utility company.

If your heater is factory set to use natural gas (fuel type can be found on the unit plate), never use the propane gas to run the unit and vice versa. Conversion can be done by using the correct conversion kit but should be done by a qualified person.

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Hot water safety and about safe temperatures

When talking about water heater safety, special attention should be given to the temperature of hot water. Most manufacturers are selling heaters where the thermostats are factory set to a temperature of 120 F because it is safer for kids and seniors but still high enough for dishwashing and laundry.

Hot water temperatures above 125 F can cause burns faster (in less than 1-2 min.) and severely damage the skin and body tissues. Also, if the temperature of hot water is below 120 F, and inside of the tank becomes prone to faster bacteria growth.

Use the thermostat to adjust the hot water temperature. Most of the thermostats include the recommended temperature, also, hot and warm range. My Rheem water heater with the Honeywell gas control valve, for example, has an arrow that shows the preferred temperature, including hot and vacation zones.

Another solution is to increase the water heater safety, avoid higher water temperatures and potential scalding - mixing valves. Mixing valves are installed on the waterline, and they are mixing hot and cold water, so the outgoing water is always in the safe range.

Temperature and pressure relief valve

The temperature and pressure relief valve (T&P) is the valve that increases the water heater safety by reducing the excessively build-up temperature and pressure inside the tank. It opens when the pressure is above the maximum allowed on the TPR valve, relieving the stress and preventing the deformation of the heater and possible explosion.

Test the T&P valve by pulling up on the handle to release some water. If water flows out, it is functioning correctly. You should never cap the discharge pipe of the TPR valve.

Other recommendations for water heater safety

  • Drain water heater per manufacturer's manual, to reduce the sediment build-up at the bottom of the tank and heater's elements.
  • Use the insulation blanket to insulate the water heater and be careful not to cover the air intake, drain, TPR valve, thermostat, and draft hood.
  • Do not remove or cover the instructions found on the water heater (i.e., lighting the pilot light).
  • Follow the instructions for the correct pilot lighting.
  • If you live in an earthquake zone, it is a good idea to strap a heater.

Note: Two of the most common reasons for the potential explosion are the gas leak and water pressure.


Either your water heater is leaking, making a noise, is exposed to chemicals, sitting in a garage or hidden in a closet, it is recommended to keep the unit maintained and in a good operating condition. If it is old or has an outdated design, the heater could be exposed to some water safety issues, so you may want to consider buying a new unit and avoid costly repairs and potential problems.

This article about water heater safety is for your reference only, while the main source of information should always be the owner's manual from the manufacturer.

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