Legionella Monitoring Standard

February 2024

The revised LCA Service Delivery Standard for Legionella Monitoring Services launched on the 1st of July 2023 with no new direct requirements for Members.

There are some minor changes to the detail in Section D that brings the different service standards more in line with each other. Members will need to make sure quotation and other communication templates used to deal with this part of the standard are updated.

Some common failings we see in Legionella Sampling & Testing are:

  • Lack of evidence that operatives involved are competent.
  • Clear Pro’s and Cons of the method used - either onsite or laboratory.
  • Variation in actions taken based on the species of Legionella identified.
  • Lack of detail in the sampling plan in detailing the scope of the service to be delivered.
  • Failure to include all laboratory details on the certificate sent to service users, specifically Sample Matrix. 


Under requirement 2 of the Code of Conduct, LCA members are required to have a process of determining what training is needed, training their staff as necessary and assessing and recording competence.  This principle must be applied to all staff involved in legionella control services.

At audit we often find that the staff involved in field delivery are well covered by the process but planning, quoting, reporting and management staff can be overlooked.  Members must be able to evidence the competence for all relevant staff, not just the ones with bottles and test kits in hand!

Pro’s and Con’s of Methods

The need to make it clear what method you are proposing in your quotation and the reason why should be clear from the quotation. If you routinely “take 1 litre samples for Legionella and analyse using Lab X with UKAS Number 9999 via the culture method” then state it in your terms of your quotation. If you have chosen to use PCR that gives results in GU instead of CFU then make sure it’s clear to your customer and explain the differences between the methods and results. 

Making this clear in your quotation from the outset gives you a clear reference point moving forwards. If your client was expecting a lab result and you provided an onsite test, then make sure client understands the implications of this. Ultimately you need to make sure that the scope covers exactly what you are proposing to do so there is no ambiguity.

Varying Legionella Species Response

All guidance issued by the HSE and the LCA makes it clear that Legionella is a genus to be concerned with; the species should not drive a varying response. Some members have a different response to Legionella pneumophila serogroup 1 compared to a Legionella species result – this is not best practice and is discouraged. A positive result is a positive result, and all positive results need to be treated equally.

Ambiguity in Service Delivery

The service offered by LCA Members should be clear from the outset and scoped accordingly. We expect sample plans and details of sample points, detail on the methods to be used and reporting details to be outlined. The method for taking the sample (Pre or Post Flush) should be clear and the reason for sampling must be understood. Members are reminded that the taking of bulk or composite samples is against the advice in the British Standard and the LCA state that this should not be done.

Laboratory Certificates and Reproduction 

The laboratory creates certificates that contain all the pertinent details supplied by the LCA Member. If an LCA Member chooses to reproduce the certificate, then all of the details must be copied exactly as presented by the laboratory. This poses some challenges, especially if the data is not automatically transferred, with the potential for transcription errors and typo’s. Most labs now work with their clients to allow them to add their logo to the certificate; this allows the Service Provider a level of banding on the certificate that may negate the need to transcribe data and thus reduce the risk of clerical errors.

If you recognise any of the above in your work, check your process, procedure and templates as soon as possible.