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Hot Water Heater Safety

Water Heater Safety

Your water heater is likely not something you think about on a regular basis, and it’s not uncommon to take it’s safe operation for granted. It may be in your garage, a utility closet, or in the corner of your basement, but it needs regular maintenance to help prevent the potential for a serious accident.

The following are some safety points to consider:

Hot Water is HOT!

The Temperature control settings on your water heater may seem simple. The settings are commonly listed as: Warm, hot, and very hot, but factory settings can vary and it’s a good idea to check the temperature at the faucet. The temperature should be at least 130 degrees Fahrenheit – and although you can still be scalded at 130 degrees, you will most likely pull your hand away before.

How to check your Hot Water Temperature

  • Turn the hot water on at the faucet nearest the water heater
  • Allow the hot water to run for 3 minutes
  • Place a cup under the faucet and fill with hot water
  • Insert a thermometer into the cup (a candy or cooking thermometer will work)
  • The temperature should read 120 degrees Fahrenheit
  • If you adjust your temperature, wait 3 hours before testing again to allow for changes

Below 120 degrees – There is a risk of exposure to Legionnaire’s disease. The Legionella bacteria can grow at temperatures below 120 degrees and you can inhale the bacteria while taking a shower from the mist.

Above 130 degrees – Increases the risk of scalding, as well as wasting energy and sediment build-up in your water heater tank. 

The Temperature Debate: Too Hot vs Too Cool

Too hot – 140 degrees Fahrenheit has been the standard for many years and is the default setting for most water heater manufacturers. However, a 3rd-degree burn can occur in adults in 6 seconds at this temperature. A 3rd-degree burn involves all of the layers of the skin, and therefore, is the most dangerous. Young children and the elderly can experience a serious hot water burn in as little as a single second.

Too cool – The risk of contracting Legionnaires’ disease (a severe form of pneumonia that is contracted by inhaling microscopic water droplets – such as from a shower) exists since the risk of colonization in hot water tanks is significant between 104 and 122 degrees Fahrenheit. According to the Mayo Clinic, it is possible to contract the disease from home plumbing systems, but most outbreaks occur in large buildings. It is thought that this might happen because of the complex systems allow the bacteria to grow and spread more easily.

Hot Water Heater Tanks can EXPLODE!

Each year a few hot water heaters explode. They could erupt with enough force to have devastating consequences to your home. This video shows an experiment conducted by the Myth Busters.

A hot water heater can explode when there is excessive temperature combined with tank corrosion. When the water temperature is below 212 degrees, the main concern is scalding. However, if the water temperature exceeds 212 degrees, the water will turn into steam. Steam takes up significantly more space than water (1,700 times more space) which will increase the tank pressure and create an explosion. The function of the temperature/pressure (T/P) valve, is to help prevent a tank from exploding if the temperature or pressure exceeds safe limits.

If you have steam instead of hot water from your faucet and/or your T/P valve is discharging water or steam, SHUT OFF the fuel source to your hot water heater. For an electric hot water heater, trip the circuit breaker. For a gas heater, shut off the gas valve. Then call a qualified Plumber.

  • NEVER go near the water heater to try to relieve the pressure yourself
  • NEVER add cool water to the tank
  • NEVER try to cool the tank by spraying with a hose
  • ALWAYS allow the water heater to cool naturally

Additional Hot Water Heater Safety Tips:

  • Keep the heater enclosure clean of dust, paper, and other combustibles.
  • Ensure that the pilot light is not lit when using flammable liquids or aerosol bug bombs.
  • If in a garage, the water heater should be raised so that the pilot light is 18″ above the floor.
  • Make sure the water heater has a good vent system. The vent should be the same diameter as the tank’s draft diverter and goes straight up and outside (without any dips).
  • If you have installed insulating pipe wrap (or any other type of insulation) ensure that it is not within 6 inches of the draft hood or the flue exhaust.
  • Although required in earthquake zones, it is a good idea to have your hot water heater secured with earthquake straps.
  • An automatic gas shutoff valve is also a worthwhile investment. It will stop the flow of gas if there is an earthquake or a dramatic increase in gas pressure.