FAQ's

Legionellosis is the collective name given to the pneumonia-like illness caused by legionella bacteria. This includes the most serious Legionnaire’s disease, as well as the similar but less serious conditions of Pontiac Fever and Lochgoilhead Fever. Legionnaire’s disease is a potentially fatal form of pneumonia.

The bacterium Legionella pneumophila and related bacteria are common in natural water sources such as rivers, lakes and reservoirs, but usually in low numbers. Since legionella bacteria are widespread in the environment they may also contaminate and grow in purpose-built water systems such as hot and cold water systems.

Legionnaires’ Disease acquired its name in 1976 when an outbreak of pneumonia occurred among persons attending a convention of the American Legion in Philadelphia, killing 34 people. Later, the bacterium causing the illness was named legionella.

Legionnaires’ disease is normally contracted by inhaling tiny droplets of water (aerosol) which are contaminated with the legionella bacteria. It is very rare that drinking town’s mains tap water is a cause and person to person spread of the disease has not been documented.

The incubation period if contracted is between 2 and 10 days. Symptoms presented are similar to flu and pneumonia, being high fever, chills, headache, muscle pain, dry coughing and difficulty breathing.

Legionella bacteria require certain conditions to multiply including moderate temperature, adequate food supply and shelter. Therefore the main aspect of legionella control is to ensure that there are no suitable conditions within the water system to potentially allow the legionella bacteria to multiply.

The criteria applied for the assessment of legionella risk involves a review of:

• Proliferation potential (Growth)
• Aerosol exposure
• Population susceptibility
The proliferation potential is governed by:
• Water temperature
• Deposits
• Presence of organisms
• Low flow areas

Although aerosol exposure (fine water droplets) is typically associated with industrial and commercial cooling towers with associated air conditioning systems, breathable droplets within a domestic home may occur from showers, spa baths and water fountains.

Legionella cannot be caught from simply drinking tap water, although there is the potential for other upsets from contaminated water.

The survey involves a visual inspection of the system, temperature measurement of the cold and hot water services, inspection of shower heads, identification of dead legs and little used outlets, (all of which may sources of bacteria growth) and photos of key features. A detailed written report is then

Rev date: 20 Jun 2021 Page 2 of 7 JPS – FAQ Page prepared containing an overview, system description, photos, system sketch. observations, risk ranking and any corrective actions. A written scheme of control is also produced to ensure future compliance.

For the survey, unrestricted access required for any boiler, cold and hot water storage along with water outlets in kitchen, utility, bath, en-suite and cloakrooms. Hot water to be at normal operating temperature.

As a guide, the assessment survey will typically take between 30 and 60 minutes, depending on the type of system (combination boiler, un-vented cylinder, vented cylinder and cold water tank); number of water outlets (kitchen, utility, cloakroom, bathrooms); location of storage cylinder / tank (cupboard, attic); presence of dead legs and little used outlets. The preparation of the report is typically completed within 48 hours later.

Depending on the water system and findings from the survey, the report is valid for 5 or 10 years with periodic desk-top reviews.