• Lisamarie Lamb

You Don’t Have Stored Water: Do You Still Need A Legionella Risk Assessment?

The law mandates you to do a legionella risk assessment, but do you need one if you don't store any water on-site? Let's look further into this idea.


If your building does not hold water, it is usually seen as a low-risk system, particularly if cold water is supplied straight from the mains supply and hot water through instantaneous heaters. Plus, if the site is small, inhabited by individuals who aren't considered at risk of legionella (such as the elderly or those with weakened immune systems), and water use throughout the day is frequent and goes throughout the whole system, it may be classified as a low-risk setting.


However, that doesn't mean you don't need a legionella risk assessment.



Photo by Anna Tarazevich from Pexels


Are There Any Other Risk Management Systems?

The presence of certain equipment, often known as 'systems,' on the site may cause problems. According to the HSE's guideline HSG 274 Part 3, an "alternative risk system" may be any of the following:


  • Humidifiers or foggers that use ultrasonic waves

  • Misting machines are used to moisten vegetables, meat, and other culinary items

  • Spray humidifiers

  • Air washers, wet scrubbers, particle scrubbers, and minor gas scrubbers

  • Water softeners

  • Emergency showers, eyebaths, and face-washing fountains

  • System of sprinklers and hose reels

  • Swimming pools with spas

  • Whirlpool tubs

  • Misting systems for horticulture

  • Vehicle washers, including automated washers for automobiles, buses, trucks, and trains

  • Dental equipment

  • Fountains and ornamental water features, including ones for sale

  • Non-disposable nebulizers for respiratory treatment

  • Plants for industrial wastewater treatment

  • Irrigation systems

  • Suppression systems for fire, dust, and odours

  • Paint spraying preparatory tools

  • Tunnel pasteurisers and related machinery


The fact that many of these systems run at or may reach temperatures that enable the bacteria to thrive makes them difficult for legionella management. In addition, they create an aerosol spray, which allows any droplets of water carrying legionella to be transferred to people through inhalation.


The HSE states unequivocally that the most challenging system for legionella danger is a spa pool, and it has produced an entire paper with comprehensive recommendations on how to manage, regulate, and prevent the bacteria from developing in these systems.


Are There Any Showers?

If your building just has toilets and washbasins, it is deemed minimal risk; however, if there are any showers, this danger is substantially increased, particularly if it is not well kept. Showers must be cleaned and disinfected regularly to stay in good condition. The HSE recommends that showers be flushed at least once a week and disinfected at least once a quarter.


It is essential that these processes be followed consistently since any failures may result in a "critical rise in legionella at the outflow," as stated by the HSE. As a result, detailed records must be kept when each control measure is implemented, so that building users are notified of any instances where it may not have been done.


You Do Need A Risk Assessment

Even if your system is as basic as possible – that is, it does not hold water, there are no other risk systems, and there are no showers – implementing a legionella risk assessment is still required. It is, in reality, a legal obligation since the responsible person must assess the probability of legionella and adopt any necessary control measures. However, extensive legionella risk-control measures are unlikely to be needed for a low-risk system that does not store water.


The legionella risk assessment is considered complete if all hazards have been appropriately handled and the legislation has been followed. However, the duty holder must evaluate the evaluation on a regular basis, and it must be seen as a continuous process.


For more information and advice, please don't hesitate to contact the experts at Assured Water Hygiene.


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