Legionella Control – What Is Legionella?

AMES Group offers Legionella control services, UK wide. Legionella is the name given to a type of water-borne bacteria which causes three potentially fatal diseases – collectively known as Legionellosis. Legionella also causes infections that lead to Legionnaires’ Disease – a potentially fatal form of pneumonia, which typically affects men more than women.

  • Legionella pneumophilia belongs to the genus Legionella.
  • Around 50 species of Legionella have been identified.
  • L.pneumophilia is responsible for approx. 90% of cases.
  • It thrives in soil and water environments.
  • At low temperatures the bacteria can’t multiply.
  • At high temperatures (over 60c) the bacteria die.

Our Legionella Control Service: Risk Groups

Our control service is designed to keep Legionella under control and prevent the spreading of the disease. The risk of contracting a legionellosis disease has been shown to be greater as age increases.  There are, however, some people with a significantly higher risk including:

  • Smokers and people with respiratory diseases.
  • Heavy drinkers.
  • People with diabetes, heart disease or lung conditions.
  • The over-45s.
  • People with kidney disease.
  • Those with impaired immune systems

How Is Legionnaire’s Disease Contracted?

People are usually affected by legionellosis after breathing in water droplets which contain Legionella bacteria. This is why it is vital for any commercial business to have a Legionella control strategy in place.

Diseases Caused By Legionella

‘Legionellosis diseases’ include: Legionnaires’ Disease, Pontiac Fever & Lochgoilhead Fever. Legionnaires’ disease is the most serious that the bacteria can cause, creating pneumonia symptoms.

Where Does Legionella Come From?

While Legionella bacteria occur naturally, they seldom form significant colonies. Artificial water systems typically offer a warmer and more favourable environment for legionella to multiply. Without a testing and control or cleaning regime in place, legionella colonies in hot or cold-water systems easily thrive.

Unfortunately, water jets, sprinklers, evaporators, misters and showers make the problem worse by creating a water aerosol. Fine water droplets – in an affected water system – spread disease very effectively.

Water Systems Which Support Large Legionella Colonies

Unfortunately, there are a wide range of conditions that encourage Legionella bacteria to multiply.


As with any living organism, legionella bacteria need certain elements in order to survive and for the bacteria to be a danger to people the following four key elements need to be in place:

  • Habitat – Shower Heads, Sprinkler hoses, taps and hot water cylinders.
  • Food Source – sediment, scale, other bacteria and certain natural organic by products found in certain hair care products.
  • Warm temperatures – Legionella bacteria thrive in temperatures of 20c – 45 c.
  • Aerosol Release – Water that is released as an aerosol can be a risk should it be contaminated with Legionella bacteria

Cooling towers, recirculated systems and water outlets commonly exhibit these features. Less widely known however are the risks posed by water services such as car washes and public showers.

Water Systems Posing A Clear Risk

Air conditioning systems, cooling towers, spa pools, Jacuzzis and swimming pools are all potential Legionella risks. However, any hot or cold-water system may pose a threat.

Equipment such as dental apparatus, NHS departments, office air-conditioners, washing facilities, vehicle cleaning machines and food manufacturing sites are a small selection of those which need regular assessment.

Industrial facilities such as manufacturing sites using ‘process water’ and also equipment such as water towers (cooling towers) also present a very real health risk. If not properly managed a great deal of affected material can be accidentally distributed. Unfortunately, most water systems pose a risk, so these examples are far from exhaustive.

AMES offers the full range of services recommended by the Government to tackle the risks involved in controlling Legionella in water systems.

For more information on Legionella risk assessments, water chlorination treatments and water sampling and analysis, contact AMES UK.

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