For most, there’s nothing easier than turning on the tap when you need a drink of water. This daily act comes with a word of caution for some locations: New research shows that a glass of warm or room-temperature tap water could harbor harmful the legionella bacteria.
What’s hiding in our pipes, and how can you protect yourself?
Legionnaires’ Disease from the Water Supply
Legionnaires’ disease is a dangerous form of pneumonia caused by the legionella bacteria. Historically, most cases of Legionnaires’ were spread by the infected patient inhaling the bacteria, but new cases have been cropping up that pinpoint warm water from a kitchen or bathroom tap as the source of infection.
The disease can be treated with prompt application of antibiotics, and is usually only fatal to individuals who have underlying health issues.
The first reported case of patients becoming infected due to legionella bacteria in the water supply was in Philadelphia in 1976, where more than 221 people were infected, including 115 hospitalizations and 34 deaths. At the time, officials were afraid that something more contagious, such as swine flu, was the culprit, but that was later disproven.
After months of searching, they were no closer to an answer and believed they might never know what had caused the outbreak.
Recent research from the journal of Applied and Environmental Microbiology may be able to explain that early outbreak. Dutch researchers have determined the best growth conditions for the legionella bacteria in water sources, such as drinking water pipes or water towers, and have concluded that drinking water that comes from natural sources, and which may have a higher concentration of dissolved organic matter, is ideal for the growth of the bacteria.
The organic material that’s dissolved in the water creates a biofilm that provides an ideal growth environment. Other conditions that promote legionella growth include:
• Warm temperatures, between 68 and 122 degrees Fahrenheit
• pH that falls between 5.0 and 8.5
• Water that is stagnant (such as that in water towers or other water storage areas)
It’s important for local water control officials to monitor the amount of legionella bacteria in their water sources, because after a bacterial colony has begun to grow, they cannot be eradicated by the chlorination typically used to purify public water supplies.
The Occupational Safety and Health Administration (OSHA) estimates that there are between 10,000 and 50,000 cases of Legionnaires’ disease in the U.S. each year. However, most of these cases are isolated and are not associated with mass outbreaks of the illness.
How to Protect Your Tap Water from Legionella Bacteria
This shouldn’t discourage you from utilizing your home’s tap water for cooking, drinking, or bathing. But prevention and preparation are key to making sure your home’s water supply is safe to drink.
Avoid stagnant water. Stagnant water provides the perfect breeding ground for legionella bacteria. If you’re away from home for a while, make sure you turn on your water taps throughout the house and let them run for a while so the stale water is replaced with fresh.
Consider water testing. OSHA has guidelines for taking water samples, and you can reach out to local or state officials to find out who in your area is responsible for water testing.
Monitor any outdoor water sources. Outdoor fountains, ornamental water features, or hot tubs and pools can all be potential growth mediums for the legionella bacteria. Taking steps to minimize legionella growth risk factors can enable you to enjoy your water features without risking the growth of the bacteria in your yard or around your home.
Stay informed. The Centers for Disease Control (CDC) and the World Health Organization (WHO) are both good resources for any information about potential legionella outbreaks in your area. Keep the risk factors in mind as well, anytime you’re dealing with a source of freshwater in your area.
Legionnaires’ disease is not as threatening as it was back in 1976, when doctors had no idea what it was, but it still presents some danger. Stay informed and make sure you take all necessary precautions to avoid being exposed to the bacteria. If you do, you can enjoy your tap water without worrying about what might be in it.
