When your water heater was installed, it was set to 120°F/49°C, which is the temperature recommended by the Department of Energy and in some states, is the law when installed. Keeping your traditional water heater at or near that temperature means the appliance continues to run to keep the water temperature up.
If you are thinking about finding ways to save money and energy, there are a few things to consider before you decide to turn down the temperature on the water heater.
Bacteria loves warm water, but not hot. If the temperature is too low it may have found an easy place to grow. But if you over-compensate and turn up the temperature too high, you may get a dangerous skin scald.
As we mentioned before, the U.S. Department of Energy recommends that to keep harmful bacteria and pathogens from multiplying, the best temperature is 120°F. In fact most new water heaters are preset to that temperature.
The Occupational Safety and Health Administration (OSHA) recommends a setting of 140°F/60°C; especially if the water travels a long way to the faucet. Water can have a chance to cool down to 120°F, making it safer to use. It is possible that 140° may scald you if it gets to the faucet quickly. Being hotter means germs are less likely to survive. If your immune system is weak, this would be an optimal setting. Also, if your dishwasher is older and cannot heat up well, a higher setting would be good.
Children and the elderly are much more susceptible to scalding as their skin tends to be thinner and reaction times slower.
What to do?
There are devices on the market today that can prevent too-hot water from coming out of your faucet. They are commonly called anti-scald valves. These valves can be installed at each point of contact with the water; insuring that your hottest temperature (140°F) at the water heater will be disbursed at the faucet at 120°F. If you are a weekend DYI’er you may be able to install them yourself; but for security you might want to call in a plumber.