• Link to X
  • Link to Facebook
  • Link to LinkedIn
  • Link to Mail
  • Call Me Back
  • About
  • Knowledge
📞 Call us on 0330 223 31 31
Water Treatment Services
  • Home
  • Water
    • Applications
      • Boiler Water Treatment Services
      • Cooling Water Treatment
      • Closed Loop Water Treatment
    • Services
      • Cooling Tower Cleaning Services UK
      • Cooling Tower Maintenance
      • Chlorine Dioxide Water Treatment Services
      • Commercial Water Softeners
      • Expert Witness Services
      • Pre-Commission Cleaning
      • Tank Reline & Repair
      • TMV Servicing
      • Water Chlorination & Disinfection
      • Water Leak Detection
      • Water Testing
        • Drinking Water Testing Services UK
        • Testing Water for Heavy Metals
        • Pool Water Testing
        • BSRIA Closed System Testing
        • SDI Testing & Analysis
        • Trade Effluent Testing
    • Training
      • Water Treatment Training
      • Basic Chemistry of Water
      • Industrial Treatment
      • Pre-Treatment
      • Boiler Treatment
      • Cooling Systems
      • Closed Systems
      • Wastewater Training
      • Advanced Treatments
      • Training Dates 2025
  • Wastewater
    • Testing Water for Heavy Metals
    • Trade Effluent Testing
    • Wastewater Training
    • Expert Witness Services
  • Chemicals
    • Water Treatment Chemicals
      • Boiler Water Treatment Chemicals
  • Air
    • Ductwork Cleaning
    • Indoor Air Quality
    • Local Exhaust Ventilation Testing
    • Mould Testing
    • Expert Witness Services
  • Energy
  • Contact
  • Click to open the search input field Click to open the search input field Search
  • Menu Menu
You are here: Home1 / Knowledge2 / Energy3 / What is a Legionella Written Scheme of Control?
Legionella written scheme of control

What is a Legionella Written Scheme of Control?

Managing the risks posed by Legionella bacteria is a legal and safety priority for any premises with a water system, especially those with complex infrastructure or vulnerable occupants. One of the most important tools for ensuring these risks are effectively controlled is the Legionella written scheme of control, a legally required document that outlines how a building’s water systems will be monitored, maintained, and managed to prevent the growth and spread of Legionella bacteria. It forms a key part of a business’s duty of care and demonstrates a proactive approach to water safety and compliance.

This article explains what a written scheme of control is, how it differs from a Legionella risk assessment, and why both are essential. It outlines what should be included in a control scheme, from water system schematics and maintenance programmes to responsible personnel and contingency planning. The article also covers the importance of regular reviews, good record keeping, and staff training to ensure that any changes or potential risks are managed swiftly and effectively.

What is a Legionella written scheme of control?

A Legionella written scheme of control is a documented plan that sets out measures to control the risk of Legionella bacteria in water systems. It ensures compliance with water safety standards and helps mitigate risks associated with exposure to Legionella bacteria and Legionnaires’ disease by maintaining safe water systems.

Is a written scheme the same as a Legionella risk assessment?

A written control scheme is not to be confused with a Legionella risk assessment – they are two distinctly different documents and should be treated as such.

A risk assessment is conducted to identify all possible Legionella risk factors in a building or facility. The written scheme of control covers all the procedures required to control the presence of Legionella bacteria in the premises covered by the risk assessment. The written scheme would normally be created after the risk assessment is completed.

Experienced engineer carrying out a Legionella risk assessment

The two documents do work together though. If you review your risk assessment and make any changes to it, you should consider whether any necessary adjustments are required to your written scheme of control also.

For example, risk assessments should be conducted regularly and checked, even if no obvious changes have occurred that would prompt this. If there is a material change to the water system or you have reason to suspect the assessment is no longer valid, this should trigger the need for the risk assessment to be reviewed. A good example would be the removal of a sink or other water outlet, or perhaps a redesign or revamp of part of the building that affects the water supply. You should then re-visit the risk assessment to reflect this.

Having done so, you can then review your written scheme of control to consider whether any changes should be made to that document also.

Legionella Risk Assessment

Is it necessary to have a written scheme of control?

In the UK a written scheme of control for Legionella is required by law, so you must have one in place that is available to review at any time.

What should be in a Legionella written scheme?

The written scheme is intended to help manage the risks associated with Legionella bacteria at a specific site, location, or venue. This could be an office building, hospital, swimming pool, or other facility. It is designed to help control the risks present at an individual location, hence why it is a legal requirement to have one.

It should include a full plan of the hot and cold-water systems present in the building. If anything changes, the scheme should be edited or rewritten to accommodate and accurately record those changes. It should also include detailed instructions on how all aspects of the system work. This may be simple or complex, depending on the size of the building and how complex the water system is.

Detailing Legionella control procedures

The written scheme of control must also cover all procedures required to help control the presence of Legionella bacteria within the water system to keep it at safe and acceptable levels. This should involve a programme of regular maintenance to ensure all system components are clean and operating in the correct manner.

Regular monitoring should also be conducted to make sure nothing is missed. This may include monitoring the hot and cold water temperatures. Water testing may also be included to ensure Legionella bacteria remains within safe levels in the system and does not rise unchecked. There should also be details of what should be done if problems arise, or if testing reveals higher than usual Legionella counts.

It is important to note that sufficient details should be provided to ensure that everyone knows what must be done if a problem does arise. That’s why the control scheme should also list all personnel involved in managing water safety at the building. It should detail who is responsible for what, and who should perform the required actions if a problem arises.

Good record keeping

Remember that the written scheme of control should detail everything required to manage and reduce the risks of exposure to Legionella bacteria in that system. While smaller businesses with fewer than five employees do not legally need to keep records, we can see that the written scheme of control is required. Therefore, it is usually easier to keep records of any testing or control measures that are undertaken and completed, for the sake of accuracy and proper coverage.

Legionella written scheme of control and risk assessment files

Legionella training and competence of key personnel

All those involved in maintaining a safe water system should also be fully aware of the risks and what they must do to complete these tasks. Thus, appropriate Legionella training should be undertaken by all these individuals. A record of this should be kept as part of the written scheme, along with any refresher training and the required dates for this to be completed.

A detailed Legionella written scheme of control can help demonstrate a responsible approach to water safety

All these details come together to show that the business or venue in question has approached its responsibilities in the correct manner. The Health and Safety Executive (HSE) or other safety regulators may require evidence of the business’ approach to managing the risks posed by Legionella. If so, the written scheme of control should cover all that is required under health and safety law. It should also provide evidence of how the Legionella responsible person and other members of staff identify and control all risks associated with Legionella.

Of course, the actions taken by one business in a specific premises will vary from those taken by another. That is the reason why a Legionella risk assessment together with a scheme of control is required by law for each venue. A new building with a modern hot and cold-water system may have very different risk factors compared to a much older building that has undergone several renovations, for example. If in doubt, it is always better to add more information than necessary to demonstrate that the risks of exposure to Legionella bacteria are being controlled effectively.

Improved contingency planning for problems and near misses

One final point is to make sure you add a plan to respond to raised levels of Legionella bacteria, or any incident that could potentially lead to this happening. This shows that you have a plan for any mishaps that could cause bacterial levels to rise. By responding quickly and following a preset plan, it is far more likely that any serious issues that do occur are dealt with quickly and effectively. Targeted and prompt action like this may help prevent an outbreak of Legionnaires’ disease altogether. This shows how important a detailed, well thought-out written scheme of control is to a business and its people.

Expert Water Treatment and Water Safety Solutions

Water Treatment Services provide a comprehensive range of water and wastewater treatment, water quality analysis, consultancy, and water engineering solutions to support business owners and those responsible for the safe and efficient operation of water systems in the workplace.

Contact us today to learn how our water treatment specialists can help you manage your water systems, maintain regulatory compliance, and ensure safe, reliable performance.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South West England and Wales), Leeds (North and North East), and Glasgow (Scotland), supported by regional teams of highly trained technicians and engineers, we deliver specialist consultancy, water quality analysis, engineering support, and risk management solutions across the UK and internationally.

Contact Us Today

Tags: legionella, Legionella Risk Assessment, legionnaires disease, Written scheme of control
You might also like
What is Antibiotic Resistance? What is Antibiotic Resistance & How Can You Help?
What is an authorising engineer water? What is an Authorising Engineer (Water)?
Can Regular Flushing Control Legionella in Hot and Cold Water? Can Regular Flushing Control Legionella in Hot & Cold Water Systems?
Can you get Legionnaires' disease from potting compost? Can You Get Legionnaires’ Disease From Potting Compost?
Legionella Testing and Water Sampling: Legionnaires Outbreak Investigations Legionella Testing and Sampling During Legionnaires’ Outbreak Investigations
Adiabatic cooling systems and open evaporative cooling towers compared Adiabatic Cooling Systems & Open Evaporative Cooling Towers Compared
5 essential steps for legionella risk management 5 Essential Steps for Legionella Risk Management
The Water Safety Group and its role in hospital safety The Water Safety Group and its Role in Hospital Safety

Search…

Search Search

What's New

  • Swimming Pool Water Testing UK: Complete Compliance Guide for Pool Operators & Facilities Managers

    Swimming Pool Water Testing UK: Complete Compliance Guide for Pool Operators & Facilities Managers

    Swimming pool water quality is one of those things …
  • Cooling Tower Compliance Check – Free Online Assessment

    Cooling Tower Compliance Check – Free Online Assessment

    How confident are you that your cooling tower management …
  • What are the 4 Main Methods for Treating Industrial Wastewater?

    What are the 4 Main Methods for Treating Industrial Wastewater?

    We all rely on water every day yet rarely …
  • Water Quality Assessment: 3 Key Areas for Safe Water Systems

    Water Quality Assessment: 3 Key Areas for Safe Water Systems

    Assessing water quality is a fundamental part of managing …
  • Water Quality Analysis for Modern Industries

    Water Quality Analysis for Modern Industries

    Understanding the quality of water used across modern industries …
  • Free Boiler Health Check & Boiler Water Treatment Assessment

    Free Boiler Health Check & Boiler Water Treatment Assessment

    Even small boiler water quality issues can lead to …

REVIEWS

4.8
Water Treatment Services is rated 4.8 out of 5 stars (based on 103 reviews)
Read our reviews

Newsletter

Receive exciting features, news, latest research and special offers! Just add your email address and we'll do the rest.

Contact us

Water Treatment Services

[email protected]

Tel: 0330 223 31 31

© Copyright 2026 - EDG Ltd. Operating as Water Treatment Services
  • Link to X
  • Link to Facebook
  • Link to LinkedIn
  • Link to Mail
  • Home
  • About
  • Careers
  • Privacy
  • Environment
  • Reviews
  • Login[learndash_login login_label=”Login/Register” logout_label=”Logout”]
  • Sitemap
Link to: Can IoT and AI Enhance Smart Water Management Technologies? Link to: Can IoT and AI Enhance Smart Water Management Technologies? Can IoT and AI Enhance Smart Water Management Technologies?Can IoT and AI Enhance Smart Water Management Technologies Link to: How to Control Legionella in Cold-Water Storage Tanks Link to: How to Control Legionella in Cold-Water Storage Tanks How to control Legionella risks in cold water storage tanksHow to Control Legionella in Cold-Water Storage Tanks
Scroll to top Scroll to top Scroll to top

This site uses cookies. By continuing to browse the site, you are agreeing to our use of cookies.

OK

Cookie and Privacy Settings



How we use cookies

We may request cookies to be set on your device. We use cookies to let us know when you visit our websites, how you interact with us, to enrich your user experience, and to customize your relationship with our website.

Click on the different category headings to find out more. You can also change some of your preferences. Note that blocking some types of cookies may impact your experience on our websites and the services we are able to offer.

Essential Website Cookies

These cookies are strictly necessary to provide you with services available through our website and to use some of its features.

Because these cookies are strictly necessary to deliver the website, refusing them will have impact how our site functions. You always can block or delete cookies by changing your browser settings and force blocking all cookies on this website. But this will always prompt you to accept/refuse cookies when revisiting our site.

We fully respect if you want to refuse cookies but to avoid asking you again and again kindly allow us to store a cookie for that. You are free to opt out any time or opt in for other cookies to get a better experience. If you refuse cookies we will remove all set cookies in our domain.

We provide you with a list of stored cookies on your computer in our domain so you can check what we stored. Due to security reasons we are not able to show or modify cookies from other domains. You can check these in your browser security settings.

Google Analytics Cookies

These cookies collect information that is used either in aggregate form to help us understand how our website is being used or how effective our marketing campaigns are, or to help us customize our website and application for you in order to enhance your experience.

If you do not want that we track your visit to our site you can disable tracking in your browser here:

Other external services

We also use different external services like Google Webfonts, Google Maps, and external Video providers. Since these providers may collect personal data like your IP address we allow you to block them here. Please be aware that this might heavily reduce the functionality and appearance of our site. Changes will take effect once you reload the page.

Google Webfont Settings:

Google Map Settings:

Google reCaptcha Settings:

Vimeo and Youtube video embeds:

Other cookies

The following cookies are also needed - You can choose if you want to allow them:

Privacy Policy

You can read about our cookies and privacy settings in detail on our Privacy Policy Page.

Privacy
Accept settingsHide notification only