Single-Family Homes or Townhomes

Legionella poses a minor risk for most homeowners. Cases of illness are more likely found in larger buildings with complex plumbing systems rather than a single-family home or townhome. However, if your home has people living in it who may be at risk (those over 50, smokers, those with weak immune systems), you will want to minimize the growth of Legionella in the plumbing of your home.

Single-Family Home

Showerheads and Faucets

Cleaning showerheads and faucet aerators at least four times per year can minimize the growth of the Legionella bacteria. Clean them more often if your home has high risk patients or if there is build-up of minerals or slimy film. To clean them:

  1. Disassemble the shower head and hose that is attached to it.
  2. Place in a bucket with a product filled with vinegar or your cleaning product of choice. Let it soak for a few minutes to remove any deposits.
  3. Rinse with fresh water and reassemble.

Water Heaters

Setting the Water Heater Temperature

Keeping your home’s water heater at 140°F will reduce the growth of Legionella. However, homeowners should install mixing valves to reduce the risk of scalding and control the water temperature at the showerhead or faucet. Contact a qualified or licensed plumber if you are unsure how to do this. Homes with high-risk individuals may consider installing tankless water systems, set at 122°F, which both reduces the risk of scalding and prevents the growth of Legionella bacteria.

Flushing the Water Heater

Emptying and refilling the hot water tank is a good practice. See more information about maintaining your water heater here.

Water Filters

Water filters that are installed at the kitchen faucet, also called point-of-use (POU) filters, should be changed according to the manufacturer’s recommendations. If the filters are not maintained, Legionella bacteria can grow on the filters and lower the water quality. Various filters are commercially available and can be found through search engines using the search terms "Legionella water filter". Commercially available filters should always be changed according to the manufacturer’s instructions, and include the following types:

  • Showerhead and faucet filters
  • Refrigerator and icemaker filters
  • Whole house water filters


Humidifiers create fine mists of water that can host and transport Legionella bacteria into your lungs, if they are not cleaned properly. Humidifiers can be complex appliances, so it is best to follow the manufacturer or the supplier’s instructions for cleaning and maintaining them. Various types of humidifiers may present different levels of risk for exposure to Legionella bacteria. In order of riskiest to least risky, the different types of humidifiers are:

  • Atomizing humidifiers – also called cool air humidifiers, use mechanical action to create a water mist that evaporates into the air stream. These units require regular cleaning.
  • Heated pan humidifiers – use a heat source to evaporate water from a pan open to the air, but do not create water mists. The “on-off” use of this device as well as the warm pan of water can create a home for bacteria to grow.
  • Direct steam-type humidifiers – these inject boiler-generated steam directly into the air. These systems do not create water mists and normally operate above 158°F, a temperature at which Legionella bacteria cannot survive.

Regularly cleaning your humidifier by following the manufacturer’s instructions will ensure it remains free of bacteria.

Evaporative Cooling Fans

No cases of Legionnaires’ disease have been associated with evaporative cooling (also commonly called “swamp coolers”) fans, and the risk is thought to be low because no aerosols are produced and cold water is used. Regular maintenance is recommended to reduce the accumulation of slime and scaling and minimize any potential Legionella risk, which includes removal of any scale, periodic cleaning of the wetted surface, and draining before storage or when not used.

Homeowners can also see multi-family homes to find additional procedures to decrease the risk of bacterial growth and transmission for:

  • Hot tubs, Jacuzzis®, spas
  • Pools and shower facilities
  • Indoor or outdoor fountains or water features
  • Solar water systems

Source: Customer Messaging on Opportunistic Pathogens in Plumbing Systems by the Water Research Foundation