Legionella

In England, the control of legionella bacteria in hot and cold water systems in commercial and apartment buildings is governed by a range of regulations, official guidance, and best practice documents. Below is a comprehensive list of all relevant regulations, Approved Codes of Practice (ACoPs), and guidance documents:

 Primary Legislation

 These are legally enforceable regulations:

 Health and Safety at Work etc. Act 1974
Employers and building owners have a duty to ensure the health and safety of employees and others, including controlling legionella risks.

 Control of Substances Hazardous to Health Regulations 2002 (COSHH)
Requires risk assessment, control, monitoring, and record-keeping for hazardous substances, including biological agents like legionella.

 Management of Health and Safety at Work Regulations 1999

Requires risk assessments and implementation of preventive/control measures for workplace hazards, including legionella.

 The Notification of Cooling Towers and Evaporative Condensers Regulations 1992
Requires local authorities to be notified of any cooling towers or evaporative condensers on-site, which are high-risk for legionella.

 Approved Code of Practice (ACoP)

 These are not law, but following them gives a strong defence in legal proceedings.

 L8 – Legionnaires’ disease: The control of legionella bacteria in water systems (ACoP L8)
Published by the Health and Safety Executive (HSE).

    • Key document for compliance.

    • Covers responsibilities, risk assessment, control measures, and record-keeping.

    • Applies to commercial and residential properties where water is supplied to tenants, employees, or visitors.

 Official Guidance Documents (HSG and HTM Series)

 These provide detailed technical advice and good practice:

 HSG274 Part 1: The control of legionella bacteria in evaporative cooling systems

  1. HSG274 Part 2: The control of legionella bacteria in hot and cold water systems
    Covers design, installation, commissioning, operation, maintenance, and monitoring of domestic water systems.

    • Applies to both commercial buildings and apartment blocks with shared systems.

    HSG274 Part 3: The control of legionella bacteria in other risk systems

  2. HTM 04-01: Safe water in healthcare premises (NHS buildings but often referenced in residential care, sheltered housing, or vulnerable settings)

 British Standards and Building Regulations

 These support compliance but are not standalone legal requirements:

 BS 8580-1:2019 – Water quality – Risk assessments for Legionella control – Code of practice. Provides guidance on how to carry out risk assessments properly.

 BS EN 806 (Parts 1–5) and BS 8558

 Guidance for the design, installation, testing and maintenance of drinking water systems.

 Water Supply (Water Fittings) Regulations 1999

 Enforced by local water undertakers, requiring systems to be designed to avoid backflow, stagnation, and contamination.

Supported by the Water Regulations Guide.

 Building Regulations 2010 (Part G – Sanitation, hot water safety and water efficiency)

 Requires provision of wholesome water and limits hot water temperatures to reduce scalding risk (indirect relevance to legionella).

 Other Relevant Guidance

 CIBSE TM13: Minimising the risk of Legionnaires’ disease

  • Widely used technical guidance from the Chartered Institution of Building Services Engineers (CIBSE).

 HSE INDG458 – Legionnaires’ disease – A brief guide for duty holders

  • Concise overview document from the HSE.

 Key Control Measures Highlighted Across Documents

 Keep hot water ≥ 60°C at source and ≥ 50°C at outlets (55°C in healthcare)

  • Keep cold water ≤ 20°C

  • Avoid dead legs and stagnation

  • Use thermostatic mixing valves (TMVs) where required, placed close to outlets

  • Regular flushing, temperature monitoring, and microbiological sampling

  • Maintain a legionella risk assessment, reviewed at least every 2 years, or when the system is changed

  • Appoint a Responsible Person for legionella control

 Summary Table  

Document Type Applies to

HSWA 1974 Law All workplaces

COSHH 2002 Law Biological hazards

MHSWR 1999 Law General risk management

ACoP L8 ACoP All buildings with water systems

HSG274 Part 2 Guidance Hot & cold water systems

BS 8580-1 British Standard Legionella risk assessments

CIBSE TM13 Industry Guide Engineering focus

Part G of Building Regs Regulation Hot water safety

Water Fittings Regs Regulation All potable water (hot & cold)