Skip to content

HSE inspections up 47% - HSE carried out over 13,200 workplace inspections in 2024/25.

Legionella Specialists

Legionella
Risk Assessment & Control

ACOP L8 · HSG274 · COSHH Regulations · Water Safety Compliance

Legionella risk assessments, water hygiene management, and compliance support under ACOP L8 and HSG274. Expert legionella control for cooling towers, hot and cold water systems, and evaporative condensers.

1,500+
Businesses Protected
50+
Countries
95%+
Retention
Book My Free Gap Analysis Call+44 (0)20 7947 9581
IOSH Chartered
ACOP L8 Compliant
HSG274 Aligned
30+ Years H&S Experience
1
Your Info
2
Choose Time

Free Health & Safety Gap Analysis

30-minute Compliance Call Valued at £750+

What Happens on Your Free Gap Analysis Call:

  • 1.30-minute consultation
  • 2.We review your current H&S arrangements
  • 3.We identify 1-10 critical compliance gaps you're missing

By submitting, you agree to our Privacy Policy and consent to Arinite contacting you about your Gap Analysis. You may also receive helpful HSE tips (unsubscribe anytime).

No Card Details Required
Free Arinite factsheet (tailored to your gaps)
Honest recommendation (audit needed or not)

Identify 1+ gaps, or you receive a £50 gift card. Only 20 consultations are available every month.

Legionella Risk Assessment & Control

Legionella Risk Assessment, Water Hygiene & Legal Compliance

Legionella bacteria pose a serious and well-recognised health risk in man-made water systems. Under the Health and Safety at Work Act 1974, the Control of Substances Hazardous to Health Regulations 2002 (COSHH), and the HSE's Approved Code of Practice L8 (ACOP L8), employers, landlords, and dutyholders must assess and control the risk of legionella exposure in all premises with water systems.

Arinite provides professional legionella risk assessments, water hygiene management, legionella control schemes, and legionella awareness training — helping organisations meet their legal obligations, protect building occupants, and maintain safe water systems compliant with ACOP L8 and HSG274.

Book a Free Legionella Compliance Review
Understanding Legionella

What Is Legionella?

Legionella is a genus of bacteria found naturally in freshwater environments — rivers, lakes, and soil.

While generally present at low, harmless levels in nature, legionella becomes a significant health risk when it:

  • Enters and colonises man-made water systems
  • Multiplies under favourable conditions (typically 20°C–45°C)
  • Is dispersed in fine water droplets (aerosols) that can be inhaled

Key characteristics of legionella bacteria:

  • Survive at low temperatures (below 20°C) in a dormant state
  • Thrive and multiply rapidly between 20°C and 45°C — the danger zone
  • Are killed at temperatures above 60°C
  • Multiply where nutrients are present — including rust, sludge, scale, algae, and biofilm
  • Over 50 species identified — Legionella pneumophila serogroup 1 causes most human infections
Health Risks

What Is Legionnaires' Disease?

Legionnaires' disease is a potentially fatal form of pneumonia caused by inhaling water droplets (aerosols) contaminated with Legionella bacteria. It has a fatality rate of approximately 10–15% and can be higher in vulnerable populations.

It is the most serious illness within a group of diseases collectively known as legionellosis, which also includes:

  • Pontiac fever — a milder, self-limiting flu-like illness
  • Lochgoilhead fever — similar to Pontiac fever

Key facts about Legionnaires' disease:

  • Not spread from person to person
  • Contracted by breathing in contaminated water aerosols
  • Incubation period is typically 2–10 days
  • Can lead to severe pneumonia, organ failure, and death if untreated
  • Around 200–500 cases are reported annually in England and Wales
Risk Groups

Who Is Most at Risk from Legionella?

Anyone can contract Legionnaires' disease, but higher-risk groups include:

People aged 45 and over (risk increases with age)

Smokers and heavy drinkers

Individuals with chronic respiratory or kidney disease

People with weakened or suppressed immune systems

Those with underlying chronic conditions such as diabetes or heart disease

Because legionella can affect anyone, controlling the risk is treated as a public health priority — not just an occupational health issue.

Legal Obligations

Employer & Dutyholder Legal Responsibilities for Legionella

Under the Health and Safety at Work Act 1974, COSHH, and the HSE's Approved Code of Practice L8 (ACOP L8), employers and dutyholders with control of premises must assess and manage legionella risks in all relevant water systems. Dutyholders include:

Employers — for their own premises and employees

Landlords — for rental properties and shared water systems

Facilities managers and building managers

Building owners and managing agents

Anyone in control of water systems in non-domestic premises

Compliance Requirements

Your Legal Duties Under ACOP L8

The HSE's Approved Code of Practice L8 (Legionnaires' disease: The control of legionella bacteria in water systems) sets out the specific duties. Dutyholders must:

Identify and Assess the Risk

  • Identify all water systems that could create a legionella risk
  • Carry out a legionella risk assessment — or arrange for a competent person to do so
  • Assess the risk from each system based on type, temperature, condition, and use

Prepare a Written Control Scheme

  • Develop a written scheme for preventing or controlling the risk of legionella exposure
  • Define control measures, monitoring procedures, and remedial actions
  • Align with HSG274 Part 2 (hot and cold water systems) or Part 1 (cooling towers)

Implement, Manage, and Monitor Controls

  • Appoint a competent Responsible Person to manage legionella controls on a day-to-day basis
  • Ensure all control measures are implemented and maintained — including temperature monitoring, flushing, and disinfection
  • Carry out regular water sampling and testing where required

Keep Records

  • Maintain records of risk assessments, control schemes, monitoring results, and remedial actions
  • Records should be kept for a minimum of 5 years
  • Ensure records are available for inspection by the HSE or local authority

Notify Authorities (Where Required)

  • Notify the local authority if cooling towers or evaporative condensers are present on site
  • Report any confirmed case of Legionnaires' disease to the HSE and Public Health England

Failure to comply with ACOP L8 and legionella legislation can result in HSE enforcement action, unlimited fines, civil claims from affected individuals, and criminal prosecution of individuals including directors and building managers.

High-Risk Water Systems

Water Systems at Greatest Legionella Risk

Certain water systems present a higher risk of legionella colonisation and aerosol generation:

Cooling Towers & Evaporative Condensers

  • Associated with the largest documented outbreaks of Legionnaires' disease
  • Require strict monitoring, water treatment, and notification to local authority
  • Must comply with HSG274 Part 1

Hot & Cold Water Systems

  • The most common source of legionella exposure in offices, hotels, and residential buildings
  • Risk increases where water temperature falls within the growth range (20°C–45°C)
  • Dead legs, stagnant water, and infrequently used outlets significantly increase risk
  • Must comply with HSG274 Part 2

Spa Pools & Hot Tubs

  • Generate fine aerosols and operate at temperatures favourable to legionella growth
  • Require enhanced water treatment, monitoring, and maintenance
  • Must comply with HSG274 Part 3

Other Systems at Risk

  • Humidifiers, misting systems, and air washers
  • Fire sprinkler systems and emergency showers (where water stagnates)
  • Decorative water features and fountains
  • Vehicle wash systems and industrial process water
Risk Factors

When Legionella Becomes a Risk

Legionella risk increases when:

Water temperature is maintained between 20°C and 45°C (the danger zone)

Water is stored or recirculated rather than flowing continuously

Water systems are poorly maintained or seldom serviced

Dead legs, blind ends, or little-used outlets allow stagnation

Biofilm, scale, rust, sludge, or organic matter accumulate in the system

Systems are not properly treated or disinfected

This is why proactive legionella risk assessment and active, ongoing management are essential — not just a one-off assessment.

Our Services

Legionella Control Services from Arinite

Arinite provides end-to-end legionella compliance support, proportionate to your premises and water systems:

Legionella Risk Assessments

Comprehensive risk assessments of all relevant water systems

Identification of legionella risks, control gaps, and remedial actions

Clear recommendations fully aligned with ACOP L8 and HSG274

Legionella Control Schemes

Development of written legionella control schemes

Monitoring regimes, responsibilities, and remedial action procedures defined

Integration with existing health and safety management systems

Responsible Person Training & Support

Legionella awareness training for appointed Responsible Persons

Understanding of ACOP L8 duties, monitoring requirements, and record-keeping

Ongoing technical support and competence development

Water Testing & Sampling

Regular water sampling programmes and legionella testing

UKAS-accredited laboratory analysis

Interpretation of results and guidance on corrective actions

Temperature Monitoring & System Review

Hot and cold water temperature monitoring regimes

Verification of control measure effectiveness

System condition reviews and deficiency identification

Record Keeping & Compliance Documentation

Legionella logbook management and maintenance records

Audit-ready documentation for HSE and local authority inspections

Ongoing compliance monitoring and review scheduling

Who This Applies To

Who Needs Legionella Risk Management?

Legionella duties apply to all premises with water systems, including:

Offices and commercial buildings

Residential buildings with shared or communal water systems

Rental properties — landlord legionella duties apply

Healthcare facilities, hospitals, and care homes

Hotels, guest houses, and leisure facilities

Schools, colleges, and universities

Industrial and manufacturing premises

Any premises with cooling towers, spa pools, or complex water systems

If your premises have a water system that stores, heats, or recirculates water, legionella legislation applies to you.

Why Arinite

Why Choose Arinite for Legionella Compliance?

IOSH Chartered Health & Safety professionals

Practical, proportionate legionella advice — not over-engineered solutions

Clear documentation fully aligned with ACOP L8 and HSG274

UKAS-accredited water testing through trusted laboratory partners

Ongoing support beyond the initial risk assessment

Experience across offices, healthcare, education, hospitality, and industrial sectors

We focus on practical legionella control and genuine compliance — not just paperwork.

Get Started

Start With a Free Legionella Compliance Review

Not sure if your legionella controls meet the requirements of ACOP L8? Start with a professional legionella gap analysis from our IOSH Chartered consultants.

Legionella compliance review valued at £750+

FAQ

Frequently Asked Questions

About Health and Safety Consultancy, Compliance Software, and Working With Arinite

Still Have Questions About Health & Safety Compliance?

Our IOSH Chartered health and safety consultants are here to help with any queries about workplace safety, compliance, or our services.

Get in TouchCall: +44 (0)20 7947 9581