Privacy Settings Legionella Testing – Where and Why - Aquacert
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Most owners realise that legionella testing is vital as part of their legionella control scheme.  But how many owners know where the legionella come from or why they are such an issue?

Where Does Legionella Originate?

In nature the bacteria are usually discovered in aquatic environments such as lakes, ponds and rivers. In their natural habitat, they survive in small numbers, competing with all the other bacteria and organisms.  Even though legionella have always been in ponds and rivers, their low populations have never been a risk to us.

Where is Legionella Usually Found?

However, in the past few generations, humans have created artificial water systems such as running hot water.  It is in these ‘man made’ water systems that legionella bacteria can grow much more quickly if the conditions are right.  The most important factor for their proliferation is temperature.  Their growth temperatures are between 20-45 °C, they grow fastest at about 38°C.  If rust, sludge, organic matter or scale are present this will encourage the survival, growth and spread of legionella bacteria.

Typical ‘man made’ water system where legionella are found include:-

  • hot and cold water systems, such as taps and showers
  • spa pools and hot tubs
  • cooling systems with cooling towers or evaporative condensers
  • water features

How do People Contract Legionella-Related Diseases?

People need to get legionella bacteria into their lungs. This occurs when we breathe in the bacteria which are contained in an aerosol. Aerosols (water vapour) are created when we run taps, showers or even flushing a toilet.  Once the bacteria are inside our lungs, they find the temperature favourable for growth.  Additionally, our bodies provide all their nutrient needs for rapid growth. For fit and healthy adults, our body’s defence systems successfully fight these invading bacteria.  Unfortunately, the immune systems and lung function elderly people are not as effective as younger people. It is this group who really suffer when they contract the disease, for aprpox 20% of them it will be fatal.  For people who are already seriously ill or have compromised immune systems, the fatality rate is far higher.

This is the reason we often associate hospitals with outbreaks of Legionnaires’ Disease. They have patients who the most susceptible to the bacteria plus huge recirculating water systems where legionella can grow.


There are actually several legionella diseases!

Legionellosis is a collective term for diseases caused by legionella bacteria including the most serious legionnaires’ disease, as well as the similar but less serious conditions of Pontiac fever and Lochgoilhead fever

Legionnaires’ Disease

A serious lung infection which is caught through air-conditioning systems, showers, hot tubs – in fact any system which produces an aerosol. It can be caught at hotels, spas, hospitals, gyms and offices.
Legionnaires’ is not usually contracted through drinking water containing the bacteria.

Pontiac & Lochgoilhead Fever

These are both a mild flu-like illness caused by legionella bacteria. Symptoms can include fever, headaches and muscle aches. Unlike Legionnaires’ disease, these illnesses do not include pneumonia.

Why Are Risk Assessments Essential?

Where systems are in place that present a risk to health and safety, it is the building’s owner’s responsibility to manage that risk.
Whenever a domestic or commercial building has water systems installed, you must legally comply with this UK regulation. The control of water systems in use must meet guidelines set out by the HSE (Health & Safety Executive) in the documents HSG 274 and L8.

A suitably qualified water expert can carry out a risk assessment and produce a report which sets out the current risks from your water systems and a control scheme to prevent or minimise them

What are the Options Available?

Legionella testing is usually one stage of the risk assessment.  Following on from this, legionella test kits are used to evaluate the effectiveness of the preventative measures.

Test kits are very easy to use  and you can order them on-line. Once you have received your water testing kit,  contact AquaCert 24 hours prior to taking the sample. This allows time to arrange a courier to collect the sample from you, (AquaCert pay for the courier). The sample(s) are incubated for 10 days and we will then supply results. Advice and recommendations will be provided and a certificate issued for your records.

Testing kits are ideal for:

• Dental and Doctor’s Surgeries
• Hotels
• Nurseries
• Hot Tub/Spa Areas
• Drinking Water Units
• Showers
• Hot Water Systems
• Care Homes
• Hospital Water Outlets

The tests are easy to use and conform to all regulations and guidelines regarding legionella testing. The results can be analysed quickly and advice provided if there are bacteria present. Aquacert will provide recommendations on remedial action steps should they be required, with all results recorded on our database and a reminder sent when the next legionella water test is due at your property.

Author: Duncan Hollis