Legionella Control & Prevention

in line with the HSE Approved Code of Practice ACOP L8


Call our Service Team on 01924 681785 - office hours Monday to Friday 9am to 5pm

If our Service Team are busy please email us at contact@waterwiseservices.co.uk

Legionella Control & Prevention measures are just as important as the risk assessment and testing.  The HSE's ACOP L8 gives guidance on effective control and prevention measures.  Failure to establish, maintain and record the measures undertaken can result in substantial fines, prosecution and even imprisonment.


In September 2016 G4S was fined £1,8000,000 plus costs of £34,000 by Chelmsford Crown Court after an inspection by Environmental Health Officers.  The inspection was carried out after an employee contracted Legionnaires Disease.  The outbreak was not linked to the workplace, but the inspection found Legionella related Health & Safety failures which put employees and the public at risk.


In May 2018 a Norfolk Hotel was fined £50,000 by Magistrates for not managing their water temperatures correctly.  Because of high hot water temperatures, a guest was scalded.  The hotel advised the local council that the water temperatures were high to address the risk of Legionella.  When carried out in a "competent" manner Legionella checks would highlight the risk from high hot water temperatures.   


The control and prevention measures that you need to put in place should be detailed in any risk assessment.  The required measures will vary from site to site and need to be carried out by someone who is competent.  Whilst measures may vary there are common measures that should be in place for every site such as flushing infrequently used outlets, regular temperature monitoring, cleaning and descale of outlets as well as regular servicing of water heaters, cooling towers and air conditioning systems.

Regular Legionella Control & Prevention Tasks


Legionella bacteria needs the correct environment to grow.  The HSE has identified that outlets that have not been used within a week present an increased risk of Legionella bacterial growth.  Infrequently used outlets need to be either removed if no longer needed or flushed on a weekly basis to minimise the risk of Legionella.

Temperature Monitoring  is far more involved than just putting a thermometer under a tap.  Outlets need to be tested in the correct sequence to ensure they meet the requirements of the ACOP L8.  To correctly carry out temperature monitoring you need to understand the requirements of the ACOP L8, how to identify a "sentinel" outlet, how to record and inspect a temperature profile, how to record stored water temperatures, how to measure temperatures into a TMV and much more

Cold Water Storage Tanks should be inspected at regular intervals to assess the risk of Legionella.  Inspection methods vary depending on the type of tank and its purpose.  It is commonly believed that cold water storage tanks should be cleaned and disinfected every year, this is not the case.  If visual inspection and/or testing show there is no risk, then there is no need for further action.

In any hot and cold-water system there are outlets which will encourage the growth of legionella bacteria.  Shower heads and other spray outlets are some of the most common areas where bacteria may grow and because they spray water there is an increased risk of passing on the bacteria.  All spray outlets such as showers should be dismantled, cleaned and disinfected on at least a quarterly basis.

Thermostatic Mixing Valves or TMV's artificially adjust water temperatures to minimise the risk of scalding.  Unfortunately, the temperature range that these valves adjust the water temperature too may promote bacterial growth.  To minimise the risk Thermostatic Mixing Valves should be serviced and cleaned on a regular basis.

Legionella Log Book


All Legionella Control & Prevention work should be recorded in the Legionella Log Book.  A Log Book is a requirement of the ACOP L8.  The HSE, CQC, Ofsted, Health & Safety Advisor, Environmental Health or any other interested party may ask to inspect your Log Book.  Failure to maintain a Legionella Log Book could be a breach of Health & Safety law.  A Legionella Log Book should contain details of the Duty Holder, Responsible Person(s) and their duties, contractors, the risk assessment, test results, a control scheme, control and prevention record, training and service records. 


As a part of your risk assessment we can produce a personalised Legionella Log Book for you.  You can then either carry out the required tasks yourself or we can carry out the work for you and maintain your Log Book.  Our Log Books have been designed by our Water Wise Engineers to be straight forward and easy to understand and maintain.  We do not produce generic books as all Log Books should be specific to the site.

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