Domestic & Legionella Water Sampling


What’s the Issue?

I am not sure if I need to be undertaking regular Legionella or drinking water testing on my premises?

How many samples should I be taking and from what areas?


What is your obligation?

The current guidance ‘HSG 274’ Part 2 gives no specific recommendations for testing for Legionella and therefore for those in control of a premises, including landlords & employers, there is no current obligation for water testing to be undertaken. However, it is a requirement that a Legionella risk assessment is undertaken to control the risk and this therefore, may indicate that sampling and analysis maybe appropriate. Also, in some cases, sampling is required, especially within care homes and healthcare premises as these are classed as substantial risk areas.



If it has been identified by the risk assessment undertaken on your premises that there is a possible risk of contamination to your water system, and you are not taking the correct precautionary measures to prevent an outbreak of Legionella then you are quite simply not abiding by the law and could end up facing a huge fine and possible criminal record.

Special consideration should also be given to occupants & patients within healthcare premises and care homes due to their susceptibility to infection. Where considered appropriate, testing for Legionella should be carried out in line with ‘BS 7592:2008 Sampling for Legionella in water and related materials’.


How we can help?

Atom Water Treatment are able to offer flexible and one off water sampling services. We work together with an independent UKAS accredited laboratory to able to provide water sampling analysis and full written reports along with any necessary recommendations required.

Contact us for a free no obligation quote including any further advice and guidance you may require.

Book a Consultation

or call the office

0203 597 5035

Microbiological and Legionella testing of your domestic water systems is usually not a requirement unless your current risk assessment or monitoring programme indicates a problem and that there is a necessity to do so.

Monitoring for Legionella should always be considered if your control regime or risk assessment has highlighted such things as inconsistency with temperatures not meeting the required criteria, disinfection concentrations are not being consistently achieved, high risk situations, such as healthcare premises with an increased population and susceptibility and water systems suspected or identified in a case of an outbreak.

If it has been established that it is appropriate for a sampling regime to be put into place, then the regulations state that this should be carried out in accordance with ‘BS 7592:2008 Sampling for Legionella organisms in water and related materials’. The regulations state that depending on the complexity of the water system, you will need to determine the appropriate number of samples to take, ensuring that they are taken from separate hot and cold outlets.

In cold water systems, samples should also be taken as required:

  • from the point of entry (or nearest outlet) if the water is supplied from a private water supply or where the temperature of the incoming mains supply is above 20°C from the cold water storage tank or tanks;
  • from the furthest and nearest outlet on each branch of the system (far and near sentinel outlets).

In hot water systems, samples should also be taken as required:

  • from the calorifier hot water outlet and from the base of the calorifier, if it safe to do so, as some systems are under considerable pressure;
  • from the furthest and nearest outlet on each branch of a single pipe system (far and near sentinel outlets);
  • from the furthest and nearest outlet on each loop of a circulating system (far and near sentinel outlets).

Analysis of water samples for Legionella should be undertaken via a UKAS accredited laboratory with the current ISO standard methods for the detection and enumeration of Legionella included within the scope of accreditation.