Legionella Risk Assessments & Statutory Water Compliance

Legionella bacteria pose a significant health and safety risk to your workforce, visitors, and the public. Legionella pneumophila—the underlying pathogen responsible for Legionnaires’ disease—is a severe and potentially fatal form of pneumonia.

The bacteria are contracted when someone inhales atomised, affected water droplets or fine aerosols suspended in the air. Because of this airborne transmission method, standard everyday building assets can easily become high-risk sources of infection if left untreated:

• Commercial showers and spray taps

• Industrial evaporative cooling towers and air handling units

• Jacuzzis, spa pools, and decorative fountains

• Commercial vehicle washing equipment and humidifiers

• Emergency fire sprinkler systems, irrigation loops, and hose reels

Direct HSE Warnings for Reopening and Stagnant Facilities

A formal Legionella Risk Assessment is particularly important where commercial facilities, retail shops, or office blocks have been closed, underutilised, or left vacant for extended periods.

Legionella bacteria thrive in warm, stagnant water zones between 20°C and 45°C. The Irish HSE and the Health and Safety Authority (HSA) have issued strict compliance notices warning employers about the heightened microbiological risks associated with stagnant building loops. When a facility sits idle, protective biocide levels (like chlorine) drop, water temperatures equalise with ambient room heat, and dangerous microbial biofilms rapidly anchor inside the pipework.

[Vacant/Idle Facility] ──> Biocide Depletion ──> Thermal Stagnation (20°C-45°C) ──> Prolific Legionella Growth

How One Eight Executes a Compliant Risk Assessment

At One Eight, our qualified environmental engineers conduct independent, comprehensive Legionella Risk Assessments strictly in line with HPSC National Guidelines and UK industry standard HSG 274 Part 2 protocols.

Our structured verification process covers:

1. Thermal Sentinel Testing

We physically measure and map the operational temperatures of hot and cold water outlets after running for specific statutory intervals. We ensure cold water stays safely below 20°C and hot water delivers above 50°C at the tap to suppress bacterial growth.

2. Physical Plant Inspections

Our engineers conduct an itemised engineering audit of your hot and cold-water storage facilities, inspecting storage tanks, chemical feed lines, and calorifiers for evidence of internal corrosion, sludge buildup, or scaling.

3. ISO 17025 Laboratory Sampling

Where your infrastructure naturally produces a spray or aerosol mist (such as cooling towers, jacuzzis, or high-risk dead-legs), we extract precise water samples. All samples are routed via a cold chain directly to an ISO 17025 accredited laboratory for verified microbiological analysis.

Your Legal Obligation Under Irish Law

Under Irish Occupational Health and Safety legislation, a strict legal obligation lies directly on employers and building owners to carry out a written risk assessment for legionella prevention and control in the workplace.

Where a risk is identified, the law dictates that appropriate control measures must be put into place and a formal, live risk management plan adopted. Our final engineering reports constitute a fully compliant Legionella Risk Assessment that can be instantly appended to your company’s mandatory Workplace Safety Statement.

Cross-Sector Field Experience: One Eight delivers site-specific risk assessments and ongoing compliance monitoring schedules across a diverse range of complex environments, including industrial manufacturing plants, hotels, regional shopping centres, multi-storey corporate office buildings, airports, and university campuses.