What To Do If You Receive A Positive Legionella Result

Following your positive Legionella result, here are some handy steps you can take to manage the Legionella risk in the water system:

1. Immediate Actions:

  • Resample the system: Repeat the testing to confirm the initial results and assess the extent of the contamination.

  • Review control measures and risk assessment: Thoroughly evaluate your current water system management practices and identify any weaknesses or areas for improvement.

  • Consider taking affected outlets or systems out of service: If necessary, temporarily remove outlets or systems with high Legionella counts to prevent further spread.

  • Cleaning and Descaling: Regularly clean and descale water tanks, pipes, and outlets to remove biofilm, sediment, rust, and scale. 

  • Implement a comprehensive flushing regime: Regularly flush infrequently used outlets and pipes to prevent stagnation and Legionella growth.

  • Disinfect the water system: Consider using chemicals or other methods to disinfect the water system, as needed

 

2. Long-term Measures:

  • Implement a water management plan (WMP): Develop and implement a comprehensive WMP to prevent future Legionella growth and control the risk.

  • Ensure proper water temperatures: Maintain hot water temperatures above the recommended level (50°C or 122°F) and cold water temperatures below the favorable range for Legionella growth (20-45°C or 68-113°F).

  • Regularly clean and maintain water systems: Regularly clean and maintain hot and cold water storage tanks, distribution pipework, and outlets.

  • Remove dead legs/dead ends in pipework: Eliminate stagnant water areas by removing unused sections of pipework.

  • Flush infrequently used outlets regularly: Flush infrequently used outlets, including showerheads and taps, at least weekly.

  • Clean and de-scale showerheads and hoses: Clean and de-scale showerheads and hoses at least quarterly.

  • Keep good water hygiene records: Maintain detailed records of all water testing, cleaning, and maintenance activities.

  • Consider point-of-use filters: Install point-of-use filters as a short-term measure to reduce Legionella risk.

 

3. Reporting and Legal Obligations:

 

  • Report cases of Legionnaires' disease: Under the Reporting of Injuries, Diseases, and Dangerous Occurrences Regulations (RIDDOR), you must report any cases of Legionnaires' disease in an employee who has worked on cooling towers or hot and cold water systems that are likely to be contaminated with Legionella.

  • Follow Health & Safety Executive (HSE) guidance: Adhere to the guidance provided in the HSE Approved Code of Practice (ACOP) L8 for managing Legionella in water systems.

  • Ensure compliance with regulations: Comply with all relevant regulations and guidelines related to water hygiene and Legionella control.