How to manage Legionella during the Coronavirus pandemic

Since the start of the Coronavirus pandemic shops, offices, sports clubs and more have had to closed there doors because of national lockdowns or local restrictions.  The measures are often applied so quickly that employers, managers, owners, etc. do not have time to consider what effect the restrictions would have on their hot & cold water systems.  The ongoing effects of the Coronavirus pandemic is leaving many people unsure of what to do.  There has also been an outburst of advice from general from health & safety advisors or governing bodies much of which has not been correct.


Health & Safety requirements, including those for Legionella do not go away during lockdowns or local restrictions.  The changes in the workplace may mean you need to put additonal measures in place.

Measures designed to minimise the risk of Coronavirus have meant that many sites have had to close or had staff numbers reduced as people are furloughed or work from home.


At the start of the lockdown measures in March 2020 many sites were basically abandoned as well as regular health and safety measures.


National and local lockdown measures have increased the risk of Legionella bacterial growth in hot & cold water systems.


As water systems have gone unused or the usage has been reduced then water may have stagnated allowing Legionella bacteria to grow.


How do you now ensure your site is safe?

Health & safety requirements have not gone away during the Coronavirus pandemic.  Measures designed to control and prevent Legionella bacteria need continue during any lockdown or restriction.  You may also need to implement additional measures to control or prevent Legionella bacterial growth.


You may have seen the various health & safety notices stating that water systems need to be cleaned, disinfected, chlorinated and tested.  THERE IS NO ON SIZE FITS ALL ANSWER.


You must consider the individual nature of your site, water system and the measures you already have in place.  You may already have done enough to ensure your hot & cold water system is safe to use such as implementing a weekly flushing regime which is one of the measures the HSE's ACOP L8 recommends when outlets become infrequently used.  It may also be a good time to get your risk assessment up to date.

Regular Flushing

During lockdown and local restrictions you may have not used your water system, or reduced staffing levels may mean there is not enough regular usage to control and prevent Legionella bacterial growth.


The Health & Safety Executive identify an infrequently used outlet as not used for a period of seven days or more.  When outlets and water systems become "infrequently used" they need to be "flushed" at least weekly.  Why?  Because water can stagnate and promote bacteria growth.  Flushing the water system and outlets will reduce the risk.

An effective flushing regime can prevent or minimise the risk of Legionella bacterial growth.  Effective flushing during any lockdown or restriction measures can make returning to work or opening any site much easier and cheaper.  If you are unsure how to effectively flush your water system we can either quote to do the work for you or we offer an online course teaching you how to flush your water system.

Legionella Testing

If you have any doubt at all about the safety of your hot & cold water system then get it tested.  Testing must always be the first step, even when there is an obvious problem with the water system.


Obvious problems would include but are not limited to dead inspects or animals in water tanks, long periods where the system has been unused or long periods where water has been at a temperature which could promote bacterial growth.

Testing benchmarks the condition of your water, the test results may show that you do not have measurable levels of Legionella bacteria, in which case you do not need to have expensive works or treatments carried out.  Even if you decide to have your system cleaned, disinfected or chlorinated you still need to test your water before and after the work so you can prove the work has been effective.

Cleaning, Disinfection & Chlorination

Your water system may or may not need to be chlorinated.  If you are concerned about your system for any reason get it tested before and after chlorination.  Without testing you cannot safely establish the need to chlorinate your system or if the chlorination has been effective.


Testing for Legionella is not the same as checking for the concentration of chlorine in the system.


When chlorinating, the chlorine must remain at the correct concentration throughout the whole system for the right length of time.  There is a tendency for service providers to increase the chlorine amount to shorten the timescale the chlorine remains in the system so they can move onto the next job.  This does not work!


If the company you are using does not test for Legionella before and after chlorination or advise the service takes less than one hour to complete, do not use them.


It is not a certificate of chlorination you need but a test certificate proving there is no Legionella.

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