Legionella in Railway Water Systems

by Peter Gunn, on 06-09-2021
Find me on:

close up ThamesLink Train

Recent press coverage both nationally and in the Greater London area highlighted further evidence that Legionella bacteria can be found lurking in little considered domestic water systems – this time within the public toilets of several Thameslink rail carriages.

Whilst the standard of reporting and research regarding this specific issue appears to be lacking and overly sensationalist, it nonetheless reminds us that an absence of due care and attention to routine maintenance can and does increase risks to water systems serving the public - including those who may simply be on a day trip or their daily commute, in this instance London. Much of the reporting, in this case, ran headlines such as ‘Potentially lethal outbreak of Legionella…’ or ‘Rail workers threaten to strike over Legionella toilet outbreak’. The presence of Legionella bacteria alone and an absence of confirmed cases of Legionnaires’ Disease, means the term ‘outbreak’ cannot be used.


Legionella Awareness Training - Now available online


The Rail, Maritime and Transport [RMT] union confirmed on the 6th of August on their website within the Members news, that three RMT members were on sick leave with suspected Legionnaires’ Disease and that there were five contaminated toilet units within three separate Class 700 carriage sets. It was also confirmed that the carriages in question have been in passenger service for a period of at least a week whilst apparently showing evidence of contamination and that ‘actionable traces of Legionella bacteria were present’ when tested.


In contrast, Thameslink’s train Services Director indicated ‘A very low level of Legionella was found to be present during testing to a small number of our Thameslink Class 700 train toilets.’ Further quotes indicated that “While it is extremely unlikely this would cause any harm, the toilets were immediately locked out of use. The trains were taken out of service and these toilets have now been drained, bleached and had their tanks completely re-filled.” It was also stated that ”There is no recorded case of anyone, ever, having contracted Legionella from a train.”


legionella blue waterAlthough it is always difficult to quantify risks in circumstances where Legionella bacteria is found to be present in domestic water systems, it is vital that property managers are sufficiently informed to appreciate the conditions which would influence Legionella risk. Health & Safety training and, specifically, uncomplicated Legionella training [awareness training], would go some way to providing competence in managing and working on domestic water systems, which in many public facilities will be relatively uncomplicated installations.


It is unclear what risk mitigation and routine maintenance measures are and were in place in the aforementioned rail carriages, certainly retrospective action has been taken to lessen [though not eliminate] the risk, but it does beg the question how many other public facilities, particularly in the London area, using water i.e. public toilets, decorative water features, drinking fountains, portable or other water humidifiers, etc. have either a less than robust monitoring and maintenance regime or no suitable water risk assessment in place.


It is worth noting that although Legionella sampling took place from the carriage toilets, they do not indicate why the water systems were being sampled at this point. Indeed, Health & Safety Executive [HSE] guidance does not mandate a routine sampling regime, but a Legionella risk assessment must be undertaken under HSE guidance for all facilities using water and which may produce aerosols, thus posing a foreseeable risk of exposure to Legionella.


Specific information regarding the management of Legionella bacteria and risk assessments can be found within the HSE's 'Legionnaires' disease: The control of Legionella bacteria in water systems. Approved Code of Practice and guidance on regulations' [L8] 4th edition which gives practical advice on the legal requirements of the relevant legislation concerning the risk from exposure to Legionella bacteria.


Additionally, 'BS 8580-1:2019 Water quality. Risk assessments for Legionella control Code of practice'. This British Standard is applicable to risk assessments being undertaken on premises, plant and systems for the first time.  It also covers reviews and assessments where a previous assessment has been undertaken and where control measures might have been implemented. 


If you have questions regarding the issues raised above or you would like to speak with one of our consultants, please click here to get in touch.

Editor’s Note: The information provided in this blog is correct at date of original publication – September 2021.

© Water Hygiene Centre 2021


Book an online legionella awareness course and get certified


About the author

Peter Gunn

Peter has been acting as an AE [water] and providing competent help services to multiple public sector and public services client in both the Midlands and North of England since 2004, and working within Legionellosis risk management since 1997. Peter currently acts as AE [water] for 11 large public services client’s including University’s, Councils, Healthcare and Constabularies.

Share your thoughts