Cleaning and Disinfection Standard

November 2023

New Requirements for 2023-24

The revised LCA Service Delivery Standard for Cleaning and Disinfection 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. 

There is a new appendix on appropriateness of measurement methods during cleaning and disinfection.  While this is a new addition, it is a clarification of existing requirements and not a new requirement.  There are specific questions regarding these elements in the 2023/24 audit form.  This form is available on the LCA website for members to use for their own internal auditing.

In auditing going forward we are moving away from non-legionella specific items and trying to focus attention on core issues.  If Members have any feedback on what is most important in the real world and where we should focus audit, please let us know.  The 2023 auditing document including checklists is available now with a highlighted changes version.


Common Failings and Areas of Focus

Some common failings we see in cleaning and disinfection are:

  • Not having an adequate process of capturing pre-quote information
  • Shortcomings in procedure to design or choose a standard method statement
  • Equipment that is not suitable or is not capable of giving the results reported
  • Reports that are not credible

These all lead to weaknesses in the cleaning and disinfection process, a potential loss of legionella control and legal exposure for LCA Members.  Our intention at audit is to identify and close weaknesses in our Members’ process.


Pre-quote Information

Under requirement 3.2 of the Code of Conduct Members are required to gather information to be able to design a service.   Cleaning and disinfection work ranges from a relatively simple tank only job to a complex cooling tower or process system.   We expect the information to be appropriately obtained from survey, conversation with prospective clients, tender specifications or other sources and documented.  If it is unavailable and assumptions are made, we expect to see the basis of those assumptions detailed in written client agreements.

Particularly with systems that are likely be fouled it is important to know the contaminants that need to be cleaned prior to planning the work.  This may affect the method that is selected, e.g. acid cleaning may be required if the contaminants identified are scale.

If the information is not known, it is impossible to design a clean and disinfection process or choose a standard process that will be effective.  This brings the work that was done into question.


Design or Standard Method Selection Procedures

The LCA requires a consistent, considered approach in design of cleaning and disinfection processes.  We often see a suite of standard method statements that are used or adapted for specific works.   If these method statements comply with the requirements of the LCA Service Delivery Standard and there is a procedure that leads to an appropriate method being selected or adapted, this is fine.  Where the cleaning and disinfection process is designed specifically for a job, we need to see evidence of a robust procedure that guides the designer.

Where there are multiple points of testing in a method statement, e.g. the tank and sentinel outlets or the tower and condense pumps, the report should reflect the requirement of the method statement.  i.e. record the levels for tank and sentinels, record the levels for tower and condense pumps and reflect these in the work report and/or certificate.

The resulting method that is used for cleaning and disinfection must reflect the pre-quote information that was gathered on the system and its condition.


Unsuitable Equipment

There are key metrics that must be recorded to evidence a disinfection process.  Commonly the disinfectant level, time and pH before addition of disinfectant, after it is added, periodically through the disinfection contact time, at the end and after disinfectant is removed or neutralised.

If a pH sensitive disinfectant is used, pH must be monitored.  Where there are specified actions to be taken at critical pH control points (extend contact time, bleed system, convert to bromine, etc) the measurement method must be able to measure these precisely enough to take the action.

Levels of disinfectant must be monitored and there are many test methods available to do this.  For critical control points like sentinels and main plant, the test method must be suitably precise to be sure the disinfection is effective and to be sure the system has not been overdosed and potentially damaged.

The new appendix to the Cleaning and Disinfection Service Delivery Standard discusses these issues in depth and is replicated at the end of this article.



LCA Assessors often see work output that is of questionable credibility.  If we can question this legal record of an important health and safety task, so could the regulator or a prosecutor.

Recording disinfectant levels that are identical to the method statement numbers with no fall in level over the course of the disinfection is not credible.

Recording no change in pH after adding sodium hypochlorite is not credible.

Recording precise 50ppm and 7.6 pH measurements when using equipment that is not capable of these measurements is not credible.

Recording the pH of a cooling system at <8 and not detailing any steps taken to reduce pH when the weekly testing records show the system consistently runs at >9 is not credible.

The LCA has not ruled out the use of simple test strips for some aspect of disinfection work.  They can be of value for intermediate outlets in a domestic system or for disinfectant presence absence checks.  They are unlikely to be suitable for critical control points where levels must be appropriately measured.

The LCA requires Members to internally audit and to conduct quality assurance on their own work.  If the LCA assessor finds any of the above examples of work that does not appear to be credible, this reflects on the competence of the Member’s internal auditor.


If you recognise some of the above in your work, check your process, procedure, water treatment chemical selection guides, programming guides and templates as soon as possible.


Appendix 1 – Appropriateness of Measurement Methods

23     Analytical measurements must be taken and recorded at various stages during and after a disinfection process to ensure the required levels were achieved for the required contact time and residual disinfectant was neutralised/flushed prior to putting the system back on line. This measurement must have a suitable degree of accuracy and precision to be meaningful in the context of the disinfection.

24     Effective disinfection, protection of the system from material damage and safety of users following disinfection depend on these levels.

25     Key points for selection of the analytical method:

                         a. The analytical method must be appropriate for the range of measurement

                         b. The measurement precision must be appropriate for the target result

                         c. The test measurement needs to be accurate enough for the control required

26     It is not always practicable to achieve a precise target disinfectant level, so it is prudent for method statements to indicate both a minimum and upper target limit to be achieved.

27     The LCA expects Members to take care to avoid gross overdosing and take suitably precise measurements of disinfectant levels at sentinel test points to ensure they reach at least at the minimum target value and ideally that the upper target limit has not been exceeded. The LCA also expects that Members use suitable methods to check the disinfectant is at safe levels after the disinfection process is complete.

28     For high level disinfection several test methods may be needed:

                         a. A precise high range method to establish that sufficient disinfectant has been achieved at key test points (titration, photometer, high range comparator, etc.)

                         b. A simple high range method to confirm presence/absence at outlets after levels have been measured at sentinel points (test strip, test paper, etc.)

                         c. A low range method to confirm the disinfectant has been removed or reduced to safe levels on completion of work after neutralisation/flushing (DPD1, low range test strip, etc.)


29     Readings reported must be the actual reading and not simply the level specified in the method statement. The record should reflect the method used. In this example the same level of disinfectant might be measured using different methods and recorded as below:

                         a. Test strip reading 30-100mg/l

                         b. Comparator reading 50-75mg/l

                         c. Titration reading 50-55mg/l

                         d. Photometer 51.2mg/l

30     Using a test strip to measure disinfectant and recording 50mg/l would not be acceptable.

31      Any pH testing equipment must be of suitable precision to differentiate between levels that might require action. i.e. where a method statement for disinfection using chlorine is based on PD855468, pH >7.6 is where contact time should be extended in hot and cold water systems. The measurement method employed must be able to differentiate between pH 7.6 and a pH of 7.7. This would normally require the use of a pH meter, photometer, or some other suitable equipment. Simple pH test strips may not have a suitable level of precision.