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What is the Difference Between Having a Legionella Risk Assessment and a Water Hygiene Service Contract?

12 September 2023

What is the Difference Between Having a Legionella Risk Assessment and a Water Hygiene Service Contract?

Two terms that you might frequently come across when you begin to look into water system management are “Legionella Risk Assessment” and a “Water Hygiene Service Contact”.

While they both revolve around water safety, they each have distinct purposes and are crucial for different aspects of water management: one is designed to identify areas of potential contamination and the other is designed to prevent it.

In this blog, we’ll delve into the key differences between the two services and how they are beneficial to your water systems.


What is a Legionella Risk Assessment?

Legionella is a type of bacteria normally found in natural water sources, such as lakes and rivers. However, it also thrives in man-made water systems, such as cooling towers, hot water tanks and plumbing networks.

The presence of legionella in your water systems can pose a significant threat to you, your staff and anyone else occupying your building, causing a potentially fatal form of pneumonia when inhaled through contaminated water droplets or vapour.

A legionella risk assessment involves a systematic evaluation of your water systems to identify potential sources of legionella growth or spread. The evaluation includes a meticulous inspection and assessment of various factors of your water system. The process includes:


System inspection

Trained professionals inspect the entire water system, including storage tanks, pipework, cooling towers, and any other components where water is stored or circulated.


Identification of hazardous areas

Potential breeding grounds for Legionella, such as stagnant water, dead legs in pipework, and areas with fluctuating water temperatures, are identified.


Risk assessment

A risk level is assigned to each potential hazard based on factors like water temperature, water quality, and the presence of biofilms or sediment.


The assessment concludes with recommendations to control and mitigate the identified risks. These recommendations can include measures like regular cleaning and disinfection, temperature control, and the implementation of monitoring and control systems.



A thorough report documenting the findings and recommendations is provided, which serves as a crucial compliance document

Typically, legionella Risk Assessments are carried out annually, or whenever there has been a significant change to your site that may have caused disruption or damage to your water systems.


What is a Water Hygiene Service Contract? 

While a legionella Risk Assessment focuses on identifying potential hazards, the purpose of a Water Hygiene Service Contract is to implement preventative measures and maintenance routines, ensuring that the cleanliness and safety of your water systems lasts over time.

While Water Hygiene Service contracts are tailored to the unique specifications of your building, they typically involve:


Cleaning and disinfection

Regular cleaning and disinfection measures are carried out to eliminate biofilms, sediment, and any potential breeding grounds for bacteria.


Temperature control

Monitoring and maintaining water temperatures within specified ranges to prevent the growth of legionella bacteria.


Sampling and testing

Routine sampling and testing of water quality to detect the presence of legionella or other types of harmful bacteria.


Record Keeping

Detailed records of all maintenance activities and test results are maintained to demonstrate compliance with regulatory requirements.



Ongoing support for staff members involved in water management to ensure they can implement preventive measures effectively.


Ensure safe and hygienic water systems with H2O Hygiene 

At H2O Hygiene, we believe that the key to healthy and safe water systems lies in proactive measures.

Our range of expert services are designed to help you identify potential risks and provide you with a comprehensive strategy to prevent them.

To find out how we can help you to achieve safe and hygienic water systems, don’t hesitate to get in touch with our water risk assessment team today, we’re on hand to answer any questions you may have.

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