Why Is It So Important to Maintain Water Hygiene?
Water hygiene maintenance such as the regular flushing of little used outlets and checks of temperature in water tanks and outlets is often overlooked, particularly in empty/vacant buildings when maintenance visits are reduced to save costs.
These checks are statutory requirements outlined in ACOP L8 Control of Legionella.
What is ACOP L8 Control of Legionella?
ACOP L8 is the Approved Code of Practice for Legionnaires’ Disease, a guide detailing all the recommended water hygiene practical measures required to remain compliant with the Health and Safety Executive (HSE).
Failure to follow ACOP L8 may result in:
- Outbreak of Legionella
- HSE Investigation
- Health and Safety Fines
- Damage to Business Reputation
So, What is Legionella?
Legionnaires’ Disease is a type of pneumonia caused by Legionella bacteria. Symptoms can include high temperature or fever, coughing, loss of appetite, muscle pains, headache, and lethargy.
The risk increases with age; smokers and people suffering from respiratory illnesses are particularly at risk.
It is treatable with antibiotics, but 1 in 10 people who get ill with Legionnaires’ Disease will die due to complications with the illness.
It has been shown that Legionella bacteria can be common in water and enter the human body via inhalation of microscopic droplets of contaminated water that are airborne as an aerosol or spray.
Many outbreaks of Legionnaires’ Disease have resulted from poorly maintained air conditioning systems, other sources include hot and cold tap outlets and showers, sprinklers, humidifiers and whirlpool spas.
A Brief History
In 1976 a mystery illness affected many US military veterans who had attended a reunion of the American Legion in Philadelphia.
Their symptoms were very much like flu or severe colds and resulted in over 200 veterans being hospitalised; tragically, 34 died.
Investigations eventually found that the illness was a form of pneumonia from Legionella bacteria that is believed to have originated in the air conditioning system of the hotel that accommodated many of the veterans.
Investigations into previous similar cases identified the earliest known outbreak to have been in 1958 when 78 people in Austin, Minnesota developed pneumonia.
There have been many other outbreaks recorded around the world since, with 604 cases reported in the UK in 2023.
How Does Legionella Multiply and What Can We Do to Prevent It?
For Legionella bacteria to exist and multiply, it requires stability, warmth and sustenance.
Stability & Sustenance: In any water system with little or no movement for a significant length of time, the bacteria can stabilise and multiply; examples include a capped section of pipe, dead leg, closed tap, or a water storage tank.
Rust or slime in pipework, silt or debris in water tanks, and scale on taps and showers all provide sustenance for the bacteria to multiply.
Regular flushing of all little used outlets will prevent Legionella bacteria from being stagnant in pipework and storage tanks and therefore unable to multiply. This may also flush out unwanted particles of rust, debris or slime within the system(s) that bacteria may be able to feed on.
Regular checks and maintenance of hot and cold water storage tanks will help prevent the build-up of debris, silt and scale, reducing sustenance that the Legionella bacteria require to multiply.
Temperature: Legionella bacteria are dormant below 20°C, will multiply between 20 and 45°C and will start to die above 50°C.
Regular (monthly) tests to confirm that the cold water in storage tanks and pipework is below 20°C will ensure that any bacteria present are dormant and unable to multiply. Likewise tests to confirm that hot water in pipework is above 50°C and in hot water storage cylinders is above 60°C will ensure that any bacteria present are killed.
Water Risk Assessment (WRA): can be used to identify potential risks to your water supply system.
A WRA involves assessing: the supply source, the surrounding area, identifying any potential or present forms of contamination, condition of storage tanks and pipework and that they are free from ingress or contamination.
There is a legal obligation to carry out a Legionella risk assessment of the water services in any workplace or business-connected premises.
An empty or vacant building presents all these risks as water becomes stagnant in storage tanks and pipework, water temperature typically rises to room temperature and silt and slime in the system are allowed to build up, the result being ideal conditions for Legionella bacteria to multiply along with other water related issues.
A vacant space within a multi-tenanted building presents a considerable risk with effective dead legs not being flushed and potentially contaminating the rest of the system within the building.
Any person(s) attending a building that has been vacant for a considerable time faces a potential risk of becoming ill with Legionnaires’ Disease when opening a water outlet (such as a tap) and inhaling microscopic water droplets from the water released.
It is therefore highly recommended to continually maintain the water systems in any buildings, especially vacant units, to avoid the possibility of a Legionella outbreak, investigations and fines from the HSE and reputational damage.
Further information can be found at:
Legionnaires’ disease. The control of legionella bacteria in water systems