Legionella Awareness: Control of Legionella in Water Systems

Legionella are a type of bacteria that thrives in water systems and are a potential cause of a detrimental type of pneumonia. Being a water borne bacteria, it is important to be aware of its thriving conditions and prevent its growth. This is more so considering the many water systems available in our homes and workplaces.

Both hot and cold-water systems can harbor these bacteria hence the need to make sure that they are closely monitored. Ideally, all these water systems should be kept in good condition in order to control the number of legionella bacteria thriving in them and further prevent their multiplication. A regular maintenance program and an inspection routine should be put in place to make sure the water systems don’t provide the right conditions for the bacteria to develop.

Controlling Legionella in Water Systems

One of the best ways to curb the growth and development of legionella is by closely managing all the water systems. The water temperatures should be controlled at predetermined levels for both cold and hot systems. In that case, here are some of the great ways to ensure legionella control in these water systems:

  • Water temperature: It is important to note that legionella thrives in temperature conditions of between 20 and 45 degrees centigrade. Therefore, you can make the bacteria dormant by setting the temperature of cold water systems below 20 degrees centigrade. In such a state, it is unlikely that they will grow and multiply. For hot water systems, the temperatures should be around 50 degrees centigrade or higher. At this point, they will be killed hence no further multiplication.  

To attain these temperatures, hot water systems should have their supplies at 60 degrees centigrade or higher at all times. Should the water recirculate all over the system, the water must return at a temperature of 50 degrees centigrade or higher every time.  Recommendations for hot water arriving at the taps must be at 50 degrees centigrade or higher in the first 1 minute while cold water should be set at 20 degrees centigrade or lower in the first 2 minutes.

  • Occasional Checks. Legionella should be monitored from time to time. There should be someone assigned the duty of maintaining the water systems. In that case, they should have enough training or facilitate getting legionella assessment services to enhance control. The scope of monitoring and assessment should include a regular check, cleaning and inspection of both types of water systems. The person in charge should pay close attention to the sentinel outlets. Sentinel outlets are those closest and furthest from the main entry point of water. The temperature of the water in distribution should also be checked.
  • Water Shower Heads. All showers except safety showers must not be fitted where they can go for over a week without use.  They should instead be installed at points where they are used regularly and flushed often to assist in minimizing the development of legionella bacteria. Shower hoses and heads must be dismantled, descaled and cleaned thoroughly at least once after every 3 months to make sure that they are ever in good condition.
  • Dealing with Stagnant Water.  Water that is allowed to stand unused and gets warmed up to temperatures higher than 20 degrees centigrade offers a good condition for bacteria to thrive.  These conditions allow the legionella bacteria to proliferate. Water stagnation commonly takes place in areas where services don’t exist anymore yet the pipe work is still in place.  In such areas, water services are not in frequent use hence are prone to stagnation. Through a formal risk assessment procedure, these conditions should be identified and action taken to remove them in order to prevent the growth of legionella. Cold water storage systems should be cleaned in these areas.
  • Water Sampling. Water samples should be collected and analyzed on an annual basis or rather be defined when doing the risk assessment. This should particularly be done for high-risk sources of water such as stagnant water systems. Such a procedure would determine when control measures should be established and conducted to safeguard all against legionella bacteria.

Any case of legionella calls for a thorough investigation together with prosecutions for non-compliance. In that cases, it is important for those in charge of the water systems to get proper training and be knowledgeable of the risks that exist. Contained here are some of the useful tips to use to create legionella awareness and control its growth and proliferation in water systems.