Legionella testing: How often should water be tested?

How often should Legionella testing be carried out?

The frequency of legionella testing is determined by your most recent Water Hygiene Risk Assessment. Whether you’re the landlord or property manager, whoever is looking after the business premises is responsible for ensuring this is up to date. How often legionella testing is recommended can vary between risk assessments, therefore a good guide to work on is around every six months. As well as this an annual sample is recommended on commercial buildings.


Legionella testing recommendations from Health & Safety England.

Although the above can be used as guidance, the legal requirements may differ slightly depending on where your commercial building is located, its size and its frequency of use. The Health and Safety Executive (HSE) had outlined several instances where a Legionella test must take place. These include:

  • If the hot and cold water system has suspected inefficiencies.
  • If hot water and cold water are not always kept at optimum temperatures.
  • If there is any doubt about disinfectant concentrations in the water.
  • If the responsible person has deemed the water hygiene system high risk.


What does Legionella testing legislation say?

There are several pieces of legislation regarding Legionella testing. The ACoP L8 “The Control of Legionella Bacteria in Water Systems” and The Health and Safety at Work Act (1974) both provide advice on legionella testing frequency. These documents exist to allow business owners and property managers to adhere to somewhat strict requirements in water hygiene.

As well as Legionella specific guidance, these pieces of legislation include frequency of water hygiene risk assessments in workplace settings. 


Which type of buildings are subject to regular Legionella testing?

There are many types of building and premises that should have Legionella testing carried out more than a typical domestic property. These tend to include commercial buildings that uses water for transactional purposes. 

If you are the business owner or property manager of any of the below businesses, you must stay up to date with relevant Legionella testing. These buildings include:

  • Gyms and workout facilities
  • Swimming pools 
  • Leisure centres and spa facilities
  • Hotels and holiday rentals
  • Retail buildings
  • Office blocks and business settings
  • Doctors surgeries and hospitals
  • Factories and warehouses


Can a business owner complete Legionella testing?

Depending on the complexity of your premises, it may be possible for yourself or a responsible person to complete your business’ Legionella testing. However it is commonly recommended to instruct a water hygiene specialist. 

This allows water hygiene screenings and Legionella testing to be completed by an expert. This expert can then follow up on any further required testing and risk assessment outcomes. When a water hygiene specialist, such as Aquastat, carries out your testing, you also have a peace of mind that your water systems meet current legal requirements.