Legionella bacteria can cause a serious illness called Legionnaires’ disease. Legionella bacteria typically originate in natural water sources, such as rivers, lakes and reservoirs.  Legionella thrives in warm, stagnant water environments and can also grow in home water systems.. This guide will help homeowners learn how to test for and treat Legionella when they receive a public notice of contamination or when you suspect someone in your household has symptoms of Legionnaires’ disease.

Understanding Legionella

Legionella is a type of bacteria that grows best in warm water, between 68-122°F. It’s often found in natural water sources but can become dangerous when it grows in water systems like hot water tanks and plumbing. Breathing in water droplets with Legionella can lead to a severe lung infection called Legionnaires’ pneumonia, which can be deadly if not treated quickly.

Preventing Legionnaires’ Disease

To stop Legionnaires’ disease, you need to keep Legionella bacteria from growing. Here are some steps to do that inside your home:

1. Water Temperature Management: Keep your water heater hot, above 140°F, and your cold water below 68°F.

2. Regular Flushing: Use all your water outlets, like taps and showers, regularly to stop water from sitting still.

3. Clean and Descale: Take apart and clean your showerheads and faucets every few months to get rid of any buildup that bacteria can grow on.

4. System Maintenance: Keep an eye on and clean systems like hot tubs and hot water tanks to stop debris and bacteria from building up.

Testing for Legionella should be done if there’s a warning about it in your area or if someone at home starts showing signs of Legionnaires’ disease. Here’s some steps to complete a DIY test if you’re aware of concerning symptoms or get public notice in your community.

DIY Legionella Testing

Testing your water for Legionella on your own is a smart way to make sure your home is safe. Here’s a step-by-step guide on how to do it:

1. Get a Test Kit: Start by buying a Legionella testing kit. You can find these online or at some home improvement stores. Look for a kit from a company with good reviews. The kit should come with clear instructions and all the tools you need to take water samples from your home.

2. Collect Samples: Once you have your kit, it’s time to collect samples from different water sources in your home. This could include your shower, kitchen tap, and water heater. Make sure to follow the instructions carefully. For example, you might need to let the water run for a certain amount of time before collecting the sample. Use the sterile containers provided in the kit to collect the water.

3. Send for Analysis: After collecting the samples, you’ll need to send them to a laboratory for testing. The kit should include a pre-addressed envelope or package for this. Make sure the samples are sealed tightly so they don’t leak or get contaminated during shipping. It’s also a good idea to send them as soon as possible after collecting them.

4. Read the Results: The lab will analyze your samples and send you a report. This report will tell you if Legionella bacteria are present in your water and in what amounts. If the report shows that there is Legionella in your water, it’s important to take steps to get rid of it.

Doing your own Legionella testing is a great way to keep an eye on the safety of your water. It’s especially a good idea if you have a hot tub, water heater, or other systems that use warm water. By following these steps, you can make sure your water is free from this harmful bacteria.

Treatment Options for Legionella

If you find Legionella in your water, you need to act quickly to get rid of it. It is important you notify your local health department or regulatory authorities as soon as possible so they can mitigate the risk if it is from a public water source.  Here are some ways to protect your own home:

1. Thermal Disinfection: This means heating your water to kill the bacteria. You’ll need to heat your water to at least 158°F and keep it at that temperature for 30 minutes or more. This high temperature will kill the Legionella bacteria. Be careful when you do this because the water will be very hot and could cause burns.

2. Chemical Disinfection: You can also use chemicals to kill the bacteria. One common chemical used for this is chlorine. If you choose this method, make sure you follow the instructions carefully. Using the right amount of chemical is important to make sure it’s effective and safe. You don’t want to use too much or too little.

3. System Flushing: Even after you’ve killed the bacteria, there might still be some left in your pipes. To make sure you get rid of all of it, you should flush out your entire water system. Turn on all your taps, showers, and any other water outlets and let the water run for a while. This will help wash away any remaining bacteria. Make sure you pay extra attention to areas where you found Legionella.

4. Professional Help: If the problem seems too big to handle on your own, or if you’re not sure what to do, it’s a good idea to get help from a professional water treatment company. They have the experience and equipment to deal with Legionella effectively. They can also give you advice on how to prevent the bacteria from coming back.

Remember, it’s important to take action as soon as you find out you have Legionella in your water. By using these treatment options, you can get rid of the bacteria and keep your water safe.


In conclusion, safeguarding against Legionella contamination in home water systems is important for maintaining a safe and healthy environment. Legionella bacteria can pose a significant health risk if allowed to grow in warm water environments. Regular maintenance practices, including temperature management, flushing, and cleaning, play a crucial role in preventing Legionnaires’ disease. DIY Legionella testing offers homeowners a proactive approach to monitoring water safety, particularly in systems prone to bacterial growth. In the event of Legionella detection, swift action, such as thermal or chemical disinfection and system flushing, is essential to eliminate the bacteria and mitigate health risks. Collaboration with local health departments and professional water treatment companies can provide additional support and guidance in effectively managing Legionella contamination. By staying vigilant and taking proactive measures, homeowners can ensure their water remains free from this harmful bacteria, promoting the well-being of their household members.