Multnomah County and Northwest Housing Alternatives working to reduce risk to residents from ongoing Legionnaires' Disease outbreak

June 17, 2021

Multnomah County Public Health is working closely with Northwest Housing Alternatives (NHA) to ensure proper water filter use after another resident of Rosemont Court was confirmed to be sick with Legionnaires’ Disease earlier today. 

This brings the total to three cases among residents since March 17 following formal water mitigation efforts. Health officials believe the three cases may be related to not using faucet filters properly.

On Monday, Northwest Housing Alternatives made the decision to offer permanent relocation assistance to some 95 residents currently living at the Rosemont Court building. Multnomah County strongly supports the move. 

Legionella is a common bacteria that can be found in many types of water sources. It infects someone after they inhale it in fine water mist. It is not spread by drinking water. It does not spread from one person to another. Most healthy people exposed to Legionella do not get sick. But for people with fragile underlying health, breathing in very small droplets of water with the bacteria can lead to severe pneumonia.

In January, the County worked with NHA to move almost 100 residents temporarily into motels after six residents were found to have Legionnaires’ Disease, and another four residents were presumed to have the illness based on symptoms. One person who spent time at a property very close to Rosemont Court was also found to have Legionnaires’ Disease. Five people were hospitalized, including one person who died. 

Extensive mitigation measures were taken to treat and test the water. The building’s water was shut off and the system was disinfected. Point-of-use water filters, as recommended by the Centers for Disease Control and Prevention (CDC), were installed in units on sink faucets and showerheads. 

Residents have since returned to the building but three have fallen ill since March 17. Multnomah County Health Officer Dr. Jennifer Vines said the County and the CDC are worried that there may still be Legionella in Rosemont Court’s water. 

“Right now we agree that using filters on all faucets should make the risk of Legionella much lower while people prepare to permanently relocate,’’ Dr. Vines said. “We know this is a close community and want to make sure that we are giving people the support they need during this transition.”

Multnomah County is providing staff outreach around the building the next few days and weeks to help support Northwest Housing Alternatives staff in checking filter fits and proper usage and to answer resident questions.

“About half of the residents at Rosemont Court have expressed interest in permanently relocating,”  said Trell Anderson, executive director of NHA. “We will continue sharing updates with residents and will be calling on our partners to support residents through this difficult time. ” 

Legionella outbreaks have been rare in Multnomah County. The Communicable Disease investigations team is working closely with the Portland Water Bureau, Oregon Health Authority, and the CDC to make sure residents of Rosemont Court and surrounding properties are confident in the safety of their water.

Anyone worried about possible symptoms of Legionnaires’ Disease should see a health care provider. Learn more about Legionnaires’ Disease here.


Frequently Asked Questions About Legionella

What is Legionella?

Legionella is a germ found naturally in freshwater, but can cause health problems if it gets into a building’s water supply. Breathing in very small droplets of water with the bacteria can lead to severe lung infection (pneumonia). Legionnaires’ does not spread from person-to-person.  Some people get a more mild illness with this bacteria - more like a flu.

What are the symptoms of Legionnaires’ disease?

Symptoms of Legionnaires’ Disease are typically:

  • Cough

  • Shortness of breath

  • Fever

  • Muscle aches

  • Headaches

  • Diarrhea

Legionnaires’ Disease can also be associated with other symptoms such as stumbling and confusion, especially in the frail elderly.  People with certain medical conditions may be at higher risk for developing Legionnaires’ Disease. They are:

  • Over age 50 

  • Smoking (current or historical)

  • Chronic lung disease, such as emphysema or COPD

  • Immune system disorders due to disease or medication

  • Widespread cancer

  • Underlying illness, such as diabetes, kidney failure, or liver failure

How does Legionella exposure happen?

People get sick from Legionella by breathing in small water droplets containing bacteria, not from drinking the water or contracting it from other people. Legionella can grow in plumbing systems when the water is warm,(between 77 – 108 degrees Fahrenheit), and has low levels of disinfectant. Common ways people breathe in water droplets with Legionella are from a cooling tower, during showering, hot tub use, or exposure to decorative fountains.

Large buildings that have complex plumbing systems are at a much greater risk to Legionella growth compared to individual homes.

Should I test my water for Legionella?

The Portland Water Bureau does not recommend testing your home plumbing for Legionella. Legionella is best controlled by properly maintaining your water system by keeping your water heater temperature hot, performing routine maintenance and cleaning your faucets and showerheads every few months.

Portland Water Bureau Recommendations for Maintaining Building Water Quality

The Portland Water Bureau controls microorganisms, including Legionella, with chlorine and by maintaining the distribution system to deliver safe and reliable drinking water to your property. Once water enters a home or building, the resident, property owners, or building manager is responsible for maintaining water quality in the home or building plumbing system. Below are steps that should be taken to control Legionella in building plumbing.

Owners or managers of large buildings
  • Develop and implement a water management program. Water management programs help you maintain your building water quality to reduce the risk of Legionella growth and spread. Use these two industry-standard resources when developing your water management plan:

  • Check your hot water system. Set your water heater to at least 140 degrees Fahrenheit. When flushing hot water taps, run the water until it reaches its highest temperature.

  • If you're using less water in your large building during the pandemic, you may need to flush or run all water outlets at least weekly. The goal is to refresh all the water in the building pipes with fresh water from the water mains underneath the street. Follow guidance from the Environmental Protection Agency on how to flush the water in your building.

Residents of Single-Family Homes

The risk of exposure to Legionella in a single-family home is relatively low but there are steps you can take to protect your family from Legionella exposure. These and more steps you can take can be found in the Portland Water Bureau’s Water Quality at Home Guide.

  • Maintain water heaters at 140 degrees: Caution! 140 degrees Fahrenheit is very hot. Take steps to prevent scalding risk at that temperature. You or a plumber can install anti-scald valves or faucets to prevent burns.

  • Follow the water heater manufacturer’s recommendations for routine maintenance to reduce the growth of Legionella and extend the life of your water heater.

  • Regularly clean your faucet aerators and shower heads every few months. Legionella can build up and grow in your faucet aerator.

Where can I learn more?