Legionella Control Measures for UK Water Systems | PTS
Following a thorough Legionella Risk Assessment, implementing robust and consistently applied control measures is the cornerstone of preventing Legionnaires’ disease and ensuring legal compliance in the UK. These measures are practical actions designed to minimise the risk of Legionella bacteria proliferating within your water systems and being dispersed as harmful aerosols. Pipe Testing Services (PTS) specialises in helping Duty Holders across the UK design, implement, and manage effective Legionella control measures tailored to their specific sites and ACOP L8 requirements.
Understanding what these controls entail and why they are critical is the first step towards a safer water system. Essentially, the goal is to create an environment within your pipework and associated plant that is inhospitable to Legionella bacteria. This usually involves careful management of water temperatures, preventing water stagnation, keeping systems clean and free from nutrients that bacteria feed on, and, where necessary, applying targeted disinfection.
Essential Legionella Control Measures:
A Practical Guide
The HSE’s ACOP L8 and technical guidance (HSG274) detail a range of control measures. The specific actions needed for your premises will be determined by your Legionella Risk Assessment, but common and essential controls include:
1. Thorough Understanding & Management of Your Water System
This is often the primary method for controlling Legionella in hot and cold water systems. Legionella bacteria thrive in temperatures between 20°C and 45°C. Therefore, control measures focus on:
- Hot Water Systems: Hot water should be stored in calorifiers or water heaters at 60°C or higher. It should then be distributed so that it reaches outlets at 50°C (or 55°C in healthcare settings) within one minute of running the tap.
- Cold Water Systems: Cold water should be stored and distributed below 20°C wherever possible. This minimises the potential for Legionella growth.
- Thermostatic Mixing Valves (TMVs): Where scalding is a risk (e.g., showers, baths, vulnerable user basins), TMVs are used to blend hot and cold water to a safe outlet temperature. However, the hot water feeding the TMV must still be at a sufficiently high temperature to control Legionella. Regular Legionella Monitoring of these temperatures is crucial.
2. Managing Water Stagnation & Ensuring Flow
Stagnant water provides ideal conditions for bacteria to multiply and for biofilm (a slimy protective layer for bacteria) to develop. Control measures include:
- Weekly Flushing: Regularly flushing little-used outlets (taps, showers) for several minutes to draw fresh water through and prevent stagnation.
- Dead Leg Removal: Identifying and removing redundant pipework ('dead legs') where water can stagnate, as highlighted in Legionella Remedial Works. If removal isn't feasible, these sections must be incorporated into the regular flushing regime.
- Cold Water Storage Tank Turnover: Ensuring correct sizing and usage of cold water storage tanks to promote regular turnover and prevent water from stagnating for long periods.
3. Keeping Water Systems Clean and Free of Contaminants
Biofilms, scale, sediment, rust, and sludge provide nutrients and protection for Legionella bacteria. Maintaining system cleanliness is therefore vital:
- Regularly inspect cold water storage tanks for cleanliness and condition (should be clean, with secure lids and insect screens).
- Clean, descale, and disinfect shower heads, hoses, and spray outlets frequently (e.g., quarterly).
- Ensure calorifiers are free from excessive scale and sludge; consider periodic draining and inspection.
- Use materials for pipework and fittings that do not encourage microbial growth (WRAS-approved).
4. Disinfection Procedures
Disinfection is a key control measure, particularly:
- For new installations or after significant alterations to the system.
- If routine monitoring shows Legionella is not under control or after stagnation periods.
- As part of a planned cleaning regime for components like cooling towers or tanks.
- Use materials for pipework and fittings that do not encourage microbial growth (WRAS-approved).
PTS provides professional Chlorination Services to BS 8558 standards for effective system disinfection.
5. Control of Aerosol Release
Minimising the creation and dispersal of breathable water droplets (aerosols) is important, as this is the primary route of infection. This includes careful design and maintenance of showers, cooling towers, spa pools, and other systems that can produce aerosols.
Implementing Your Documented Control Scheme
All these control measures should be clearly documented within your site-specific written scheme of control, as required by ACOP L8. This document, based on your Legionella Risk Assessment, outlines how you will manage your water systems, detailing the control measures, who is responsible for them, the frequency of checks, and what to do if controls are found to be ineffective. PTS can assist in developing or reviewing this critical documentation.
Ongoing Management, Monitoring, and Record Keeping
Implementing control measures is not a one-off task. They require consistent management and ongoing Legionella Monitoring to ensure they remain effective. This includes regular temperature checks, flushing, inspections, and keeping meticulous records of all activities undertaken. These records are vital for demonstrating compliance and for reviewing the effectiveness of your control scheme over time. PTS provides comprehensive support for these ongoing management tasks.
Why Partner with PTS for Implementing Legionella Control Measures?
Successfully implementing and managing Legionella control measures requires expertise, consistency, and a thorough understanding of ACOP L8 and HSG274. Pipe Testing Services offers Duty Holders across the UK a reliable partnership in achieving and maintaining water system safety. Our experienced consultants can help you translate the findings of your Legionella Risk Assessment into a practical and effective written scheme of control.
Our trained technicians are skilled in carrying out the physical control measures, from routine temperature monitoring and flushing regimes to full system disinfections using our Chlorination Services. We provide clear, compliant record-keeping systems and can advise on the appropriate frequencies for all checks. By integrating our Legionella Monitoring and Remedial Works capabilities, PTS offers a truly holistic approach to managing your Legionella risks, ensuring your control measures are not only implemented correctly but are also consistently effective.
Ensure Effective Legionella Control with PTS
Implement robust, compliant, and practical Legionella control measures to safeguard your water systems and protect building occupants. Pipe Testing Services offers expert guidance and hands-on support across the UK.
Contact our water hygiene specialists today to discuss your requirements for implementing or reviewing your Legionella control measures:
- Phone: 01922 451646
- Email: enquiries@legionellatestingservices.co.uk
- Address: Unit 27 Birchbrook Industrial Estate, Shenstone, Lichfield, Staffs, WS14 0DJ
Legionella Control Measures - FAQs
What are the most important Legionella control measures?
The two primary control measures for many systems are temperature control (keeping hot water hot and cold water cold) and preventing water stagnation (through regular flushing and good system design). System cleanliness is also critical.
How often should I check my Legionella control measures?
The frequency of checks (e.g., daily, weekly, monthly, quarterly, annually) for different control measures should be defined in your Legionella Risk Assessment and written scheme, based on ACOP L8/HSG274 guidance and system risk.
Can I implement Legionella control measures myself?
Some routine checks (like weekly flushing of some outlets) can be done by trained site staff. However, more technical tasks (like system disinfections, temperature validation across large systems, internal tank inspections) require specific competence and equipment. Using a specialist provider like PTS ensures measures are implemented correctly and safely.
Does ACOP L8 specify exactly what control measures to use?
ACOP L8 and HSG274 provide detailed guidance on common control measures and when they are appropriate. However, the specific measures implemented must be based on your site-specific Legionella Risk Assessment.
How does PTS ensure the control measures they implement are effective?
We follow industry best practices, use calibrated equipment, ensure our staff are trained and competent, and often recommend verification methods such as post-disinfection Legionella Testing to confirm effectiveness.