How Hot Is Hot Enough for a Home Water Heater?

Learn how hot to set your home water heater from the Pros at Calhoun Plumbing.

How Hot Is Hot Enough for a Home Water Heater?

Calhoun Plumbing

July 25, 2019

Hot water can fight germs and infestations in amazing ways, but only when it’s hot enough. Experts have advised people to set their water heaters to a maximum temperature of 120 degrees Fahrenheit. However, researchers now advise people to set their water heaters at higher temperatures.

Who’s giving the right advice when it comes to hot water temperatures? It turns out, higher water temperatures are best. Here are several compelling reasons to raise the temperature setting on your water heater and how to keep your family safe from scalding water when you do.

Water Must Be Hotter to Prevent Legionnaire’s Disease

Home and industrial water heaters are thought to be responsible for known outbreaks of Legionnaire’s disease. The bacteria responsible for Legionnaire’s disease is called Legionella pneumophila. As its name suggests, the aquatic bacteria causes lung problems including pneumonia.

Other signs of Legionnaire’s disease include:

  • Muscle aches
  • Chills
  • Headache
  • Tiredness
  • Stomach issues

Each year, about 22,000 cases of Legionnaires disease are diagnosed in the U.S. Part of the problem is that Legionnaire’s disease bacteria (LDB) thrive in temperatures between 68 and 119 degrees Fahrenheit. The higher end of this scale is within the temperature range of many water-heater interiors.

Sediment and scale inside water heaters provide the perfect environment for LDB. Then, the disease is spread to household members through shower spray and mist from baths or dishwater.

Set your water heater to a maximum temperature140 degrees Fahrenheit to kill LDB. LDB die in just over a half hour at 140 degrees Fahrenheit. At 120 degrees Fahrenheit, the LDB will stop multiplying, but they will stay alive and spread to faucets and sprayers.

Water Needs Higher Temperatures to Sanitize Dishes Alone

Do you want to kill bacteria with hot water only? Your water heater would have to produce water that’s dangerously hot to wipe out all of the germs on dirty pots, pans, glasses, and dishes.

Hot water must reach temperatures between 165 and 180 degrees Fahrenheit to sanitize dishes, and the dishes need to be exposed to hot water for at least 30 seconds. Your home dishwasher has a built-in water heater to raise temperatures during wash and rinse cycles.

However, keeping your hot water at a higher temperature setting helps your dishwasher work more efficiently. The appliance won’t need as much energy to heat the water. You should also run hot water into the kitchen area before starting your dishwasher, so the initial water sprayed into the machine is already hot.

High Water Temperatures Kill Bugs

Some of the most insidious household pests are killed by high heat and being submerged in hot water. For example, bedbugs can be killed with soapy water at a temperature anywhere between 117 and 122 degrees Fahrenheit.

Lice and nits die in hot water that’s at least 130 degrees Fahrenheit. However, you should use the dryer on the highest heat setting as a backup heat treatment for bed bugs and lice.

Hot Water Burns Can Be Prevented With New Fixtures

Burns from hot water can happen after five seconds of exposure to water at 131 degrees Fahrenheit. When you raise your water heater temperature, hire a licensed plumber to install devices that limit the hot water temperatures at sinks, tubs, and showers.

Anti-scald devices are available in three types, which are:

  • Temperature-actuated mixing valves
  • Automatic compensating mixing valves
  • Temperature-limiting devices

These devices can be custom-set to mix water at the hot-water source or the faucet. Your plumbing professional can explain the pros and cons of each type of anti-scald device for your plumbing system.

When your water heater won’t get hot enough, or you need anti-scald devices, contact the experts at Calhoun Plumbing. We install anti-scald fixtures and water heaters for homes in Columbus, OH, and surrounding areas.