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Further Information


What is Legionnaires’ Disease?

Legionnaires’ Disease is one of a group of diseases collectively known as Legionellosis. Others are Pontiac fever and Lochgoilhead fever. Of these infections, Legionnaires’ Disease is the most serious.

Do I need to do anything about Legionnaires disease (Legionellosis)?

Where you employ staff, have contractors or members of the public in contact with your water systems or more significantly spray from your water systems it is likely that you fall within HSE guidelines and the appropriate Code of Conduct and then you are obliged to take action.

What are the current regulations?

L8 was published in January 2001. Should you wish to get a copy, the ISBN is 0717617726, cost is £8.00 from HSE Books or

Do I need to have Legionella tests done?

The testing for Legionella is not currently a requirement, however can be a valuable tool as part of a more in depth control programme. Regular testing may indicate weakness in a programme or system which allows remedial actions to be taken. Not detected results should not however be interpreted as “no problem – never a problem”. Inspections by HSE and Environmental Health Officers frequently ask if testing has been undertaken.

Who is most at risk?

Those most at risk include smokers, alcoholics and people suffering from cancer, diabetes, chronic respiratory or kidney disease. But healthy people can also be infected. Most reported cases have been in people aged between 40 and 70; men are more likely to be affected than women.

Where is Legionella found?

Legionella bacteria are widespread in natural sources of water including rivers, streams and ponds and may even be found in soil. They are also found in many re-circulating and hot and cold water systems. Outbreaks of Legionnaires’ Disease have occurred in or near large building complexes such as hotels, hospitals, offices and factories. There is no evidence that water systems in domestic homes present any risk.

If Legionella is so widespread, why aren’t there more outbreaks?

Infection is caused by people breathing in water droplets contaminated with Legionella bacteria. But for infection to occur a chain of events has to take place and fortunately this does not happen very often. The chain includes:

Cooling towers, such as those which form part of an air conditioning system, can represent a particular hazard because they readily generate fine water droplets and there is an air current to carry them away. Because they are often located on roof-tops there is a potential for infecting large numbers of people. The bacteria may also colonize hot and cold water systems – showers and spa baths have been associated with infection.

How can the risk be reduced?

Since Legionella is widespread in the environment, it cannot be prevented from entering water systems. However, the risk of an outbreak developing can be reduced by taking the following precautions:

Hot and cold water services

Cooling towers

Other water systems

Precautions are necessary wherever water conditions are likely to support the growth of bacteria and there is a means of dispersing droplets, e.g. commercial spa baths and humidifiers.

What are the legal duties?

The Health and Safety at Work etc Act 1974 and the Control of Substances Hazardous to Health Regulations 1988 both apply. Practical guidance on the legal duties is given in an Approved Code of Practice from the Health and Safety Commission. The Code provides a basic framework of risk management for preventing further outbreaks of the disease. In Scotland, Legionellosis is a notifiable disease.

Are bacteria a problem in the water at home?

Not normally when from mains supply. Water supply companies are required to supply wholesome water, this means a range of bacteria are monitored during routine tests, treatment is also carried out to control bacterial contamination. What happens once the water becomes yours (after the stop cock) is not controlled by the water supply companies. Tanks, dead legs, unused and dirty outlets can cause a local bacterial problem.

What can I do about the rusty tap water?

Sometimes the water pipes around houses, offices and factories become corroded, this results in Red water – rusty water coming through the taps. This can normally be treated using a WRC approved treatment which provides a coating inside the pipes, when this coating is established and maintained the rusty water becomes a thing of the past. The product used for this also provides a degree of scale control and can be used in drinking water.

What can I put down the drain?

There are normally at least two types of drain on most sites. These are Foul drain, which can take most domestic effluent and a range of industrial effluents within prescribed consent limits – this effluent is subject to treatment prior to discharge into streams. Surface drains which are designed to take surface water run off i.e. rain water and this normally goes untreated to local rivers or water courses. Some sites have their own processing plant and others have large effluent holding tanks, the contents of which are periodically tankered away for disposal.

If there is any doubt regarding the drains on site it is wise to obtain or prepare a plan and check all discharges to ensure the correct use. The environment agency is a valuable source of information and is also the regulatory body for, amongst other things, effluent discharges.

What can I do about the scale in my kettle? / Do I need A Filter On My Drinking Tap?

The water supply companies are required to supply wholesome water. This includes a certain amount of naturally occurring chemical and biological contaminants and may include some treatment products such as chlorine for bacterial control and fluorine to reduce tooth decay. Filters at the base level can remove particles, more sophisticated RO filters can produce chemically very pure water. Filters range from jug type units on the counter top to those plumbed into the kitchen sink. If you don’t like your kettle furring up a filter may be what you need.

What can I do about the scum in my bath? / Do I need a water softener & what do they do?

A water softener removes Calcium and Magnesium hardness from the water and prevents scale, this makes the water soft and can provide a wide number of benefits. Industrially, the benefits are significant – no hardness reduces energy wastage and can contribute to significant water savings and down-time costs. Softeners are almost always used on cooling systems and boilers industrially. Domestically, many people prefer washing in soft water and soft water uses less soap.