Legionella Risk Assessment



We are committed to providing our customers with an exceptional level of customer service. Over 90% of our first-time clients return to us for legionella risk assessments. They know that we only work with effective equipment, guarantee competitive prices, and focus on health and safety.



Legionella Bacteria is naturally found in watercourses such as rivers, lochs, ponds and reservoirs but in low numbers. When this water is introduced into a man-made water system, the bacteria could proliferate rapidly. 

Legionella is dormant in temperatures below 20°C and multiplies in temperatures between 20°C and 45°C. Legionella cannot survive in temperatures above 60°C. Legionella enters your body through your respiratory system through vapours or droplets of water and has a 10% mortality rate. More information about Legionella and its effects can be found on the Health Protection Scotland Website.



At pHX Water, we take the hassle away from water maintenance. You can depend on us for all the cleaning, sampling, and reporting services you need to meet water maintenance regulations and provide safe drinking water.

We can protect your customers, clients, and employees from harmful bacteria.

Legionella is a naturally occurring form of bacteria found in water sources such as rivers, lochs, ponds, and reservoirs. When water is pumped into your hot water tank or cold storage tank, legionella has a new breeding ground. If not properly managed, the non-hazardous amounts of legionella can rapidly multiply and pose a threat to health.

Legionella enters the body through the respiratory system via droplets of water. Even a small amount of legionella causes a 10% mortality rate.

Water systems are an often overlooked yet essential part of any commercial or industrial building. Without a water tank, your building would not be able to serve its purpose. It is important to regularly check the levels of bacteria in your water tank.

Our legionella risk assessment and water tank cleaning services identify and eliminate harmful levels of bacteria, biofilm, and debris in your tank.


Who Is at Risk of Legionella?

In Scotland, any building that has a private water supply must be subject to a legionella risk assessment.

Any water system that stores and/or recirculates water is at high risk of breeding excess amounts of legionella. Below are a few water vessels that should be considered for a regular legionella risk assessment.

  • Hot water tanks
  • Cold storage tanks
  • Hot tubs
  • Swimming pools

What Causes an Increase in Legionella?

Legionella is present in small amounts in natural water sources.

Once stored in your hot or cold water tank, legionella is at constant risk of breeding. Temperature is the most important factor when considering how to avoid excess amounts of legionella.

Here are a few important facts about legionella:

  • It is dormant in temperatures below 20°C
  • It cannot survive in temperatures above 60°C
  • It begins to breed between 20°C and 45°

In many cases, it is difficult to maintain a constant water tank temperature. This is why it is crucial to book an annual risk assessment.


Legionella Risk Assessment Scotland

When it comes to legionella risk assessments, it pays to speak to the experts. We conduct assessments for businesses, organisations, and landlords all across Perth, Fife, Edinburgh, and the rest of Scotland.

Our specialists focus on providing a comprehensive service. Once we have assessed your water tank, we create a report that contains a simple traffic light system. As you would expect, red means that urgent attention is required whereas green means that there is no cause for concern.

With our reports, it has never been easier to cut through the fluff and get to the heart of the matter.

Here are a few things you can expect with every legionella risk assessment:

  • Simple layout
  • Traffic light system
  • Legionella control scheme
  • A detailed assessment of the controls needed
  • Frequency of legionella risk assessment control guidelines
  • Legionella risk assessment template to document the controls

We work with our clients to create positive outcomes. Our support extends far beyond the report you receive. If you have any questions about your risk assessment outcomes, do not hesitate to give our team a call.

Commercial Water Tank (sectional potable water tank)   Calorifier Boiler - Heating Hot Water



Water systems that store or recirculate water are at a higher risk. These may include cold water storage tanks where poor hygienic conditions can provide a nutrient source for the bacteria or hot water vessels with non-conforming temperatures allowing the bacteria to multiply than be released into the system. 

This may also include recreational water systems such as hot tubs or swimming pools where stored water is at a temperature that would allow Legionella to multiply. This means that everyone in Scotland in is at risk of getting Legionella if a Legionella Risk Assessment isn’t completed by a competent person.



At pHX water, we are here to ensure that your drinking water is safe for human consumption. You must organise an annual legionella risk assessment if you have a private water supply. This includes:

  • Landlords
  • Commercial building managers
  • Industrial site managers

You can find more information about the frequency of legionella risk assessment services for landlords on Landlord Accreditation Scotland.



We’ll assess all your water systems to British Standards, ensuring they’re kept in a safe condition to prevent the growth of Legionella. Our certified engineers will tailor a flexible action plan using a traffic light system to make it easy for you to understand and use as a working document. 

You will also receive a Legionella control scheme with every risk assessment that details what controls are required and at what frequency to ensure that your business is compliant. Your service can also include interim health checks to monitor your water systems and minimise future risks.



  1. We will complete a full assessment of all site assets with photographic evidence while completing the Legionella control scheme documentation
  2. Full system & outlet survey
  3. Summary schematic of the water system
  4. Practical recommendations
  5. Check of all legal and guideline requirements
  6. Health & Safety Executive ACOP L8 & HSG 274 guidance
  7. Coverage of HTM04-1 for Healthcare premises
  8. Coverage of HTM01-05 for Dental premises
  9. Alignment with BS8580



Landlords in Scotland must ensure a legionella risk assessment has been carried out to determine the level of risk of any of the water in the rental property becoming contaminated with Legionella. The Legionella risk assessment can be carried out by anyone competent to do so.

Most rented properties will be low risk, but it is a requirement for landlords to ensure that the risk of exposure to tenants and visitors by Legionella is properly assessed and controlled. This is a legal obligation and is enforced by the Health & Safety Executive (HSE).

Implementing simple, proportionate, and appropriate control measures will ensure the risk of contamination remains low. At PHX water our certified engineers will tailor a flexible action plan using a traffic light system to make it easy for you to understand and use as a working document. You will also receive a Legionella control scheme with every risk assessment that details what controls are required and at what frequency to ensure that your properties are compliant.

For most domestic hot and cold-water systems, the temperature is the most reliable way of ensuring the risk of exposure to Legionella bacteria is minimised i.e., keep the hot water hot, cold water cold and keep it moving. Our engineers will provide all this information to you in an easy-to-understand report and can assist with regular maintenance as part of your legionella risk assessment.

During our Legionella Risk Assessment, we will:

  1. Flush out the system prior to letting the property
  2. Identify and remove any debris getting into the system e.g ensuring the cold-water tanks, where fitted have a tight-fitting lid and remain uncontaminated
  3. We can set the control parameters to ensure water is stored at the correct temperature
  4. Identify and redundant pipework for removal



  1. Inform the landlord if the hot water system is not heating properly
  2. Inform the landlord if the cold-water system is not running cold

The responsibility of the prevention of Legionella stays with the landlord and a regular legionella risk assessment is required to make sure they adhere to the law. Landlords should be aware that the risk of Legionella may increase if the property is unoccupied even for a short time For full details of legal responsibilities and control measures landlords should visit the HSE website.



PHX Water is a Scottish Water company, based in Perth. PHX Water provide services throughout Scotland, our Perth base is in the heart of Scotland giving us a central location to all of our major towns and cities; Aberdeen, Inverness, Perth, Dundee, Stirling, Glasgow and Edinburgh.


Contact pHX Water

With rules and regulations constantly changing, it is important to speak to the experts. Our team have been working on commercial, industrial, and residential hot and cold water tanks for years. People all over Scotland trust us to stay up-to-date on the latest news, certificates, and laws. When you choose pHX Water, you can rest assured you are in safe hands.

To book a legionella risk assessment, or to make general inquiries, call us on 01738 472149. If you need to speak to someone in an emergency outside of normal working hours, call 07503 343328.





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