WATER SYSTEM SAFETY
the purchaser is expected to buy the product and then validate it themselves. This contradicts the Legionella ACoP L8
(Fourth edition), which states in paragraph 76: ‘Suppliers of products and services – including consultancy and water treatment services, aimed at preventing or controlling the risk of exposure to Legionella bacteria, must – so far as is reasonably practicable – ensure that: (a) measures intended to control the risk of exposure to Legionella bacteria are so designed and implemented that they will be effective, safe, and without risks to health when used at work.’
A tap diffuser. effectiveness and safety.
n Limited or vague information: Promotions that provide limited details about the product’s mode of action, ingredients, or testing methods, may be attempting to hide important information.
UV system instance An IHEEM-registered AE (Water) colleague was presented with a UV system fitted post-mains cold water delivery to a building, and prior to two cold water storage tanks, for evaluation. My colleague questioned the need for such a unit, as water should be supplied as wholesome, and went on to question the efficacy of the product. The supplier was asked for validation data, and to share all independent tests of what biological control it has achieved to give customer assurance of whatever waterborne pathogens the product it is going to kill. The sales information had stated that the unit provides ‘UV disinfection that says bye bye to bacteria’, and ‘destroys 99.99% of microorganisms that pass through it’. The supplier returned information which
showed no validation data nor efficacy studies to validate these claims. The bacterial control section of its supplied data stated that ‘The unit should be independently tested and validated in accordance with BS EN 14897:2006 + A1:2007.’ In essence this was stating that
‘‘
Anti-Legionella valve One company was advertising an anti- Legionella valve. After reading the information supplied it would appear that the valve maintains circulation, thus reducing stagnation in a section of the cold water system. Potentially the water supply may or may not contain hundreds of species of organisms, which may or may not be pathogenic, and to focus on Legionella in my opinion is using scare tactics to promote the products. Another company marketing a Legionella test kit has made several misleading and incorrect statements, such as: n ‘In the majority of cases, the property owner is not legally required to carry out water testing. Legionella testing is an exception’. This is incorrect. Legionella testing is only required when the risk assessment or monitoring indicates there is a problem, and it is not a legal requirement.
n ‘Legionella can enter water systems through various means – such as contaminated water supplies, cooling towers, hot water tanks, showers, and decorative fountains. It thrives in warm water environments, making monitoring and testing these systems regularly essential’. With the exception of cooling towers, regular testing is not essential unless the risk assessment or monitoring indicates there is a problem.
n ‘You may simply take the water sample when and where you want’. The choice of sampling point location requires a detailed knowledge of the layout of the water system to be examined, and an appreciation of the ecology of the
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It is important to note that using non- validated products for building water hygiene can have serious consequences
organism. Whenever possible, samples should be collected at the time when the numbers of legionellae are most likely to be at their highest, and the risk of legionellae being present is therefore at its greatest.
n ‘Action is needed if the Legionella concentration in the water exceeds the indicated limit value of 100 cfu (colony- forming units) per 100 millilitres of water’. This is incorrect. The action level for Legionella should be 100 cfu/L (or 100cfu/1000ml).
n ‘Thermal disinfection is the first step in combating Legionella. The entire drinking water system is heated to 70°C for at least three minutes’. This method is only applicable to the hot water system, and requires raising the temperature of the whole contents of the calorifier and circulating water for at least an hour. Every hot water outlet throughout the system must then be flushed, and – to be effective – the temperature at the calorifier should be maintained high enough to ensure that the temperature at the outlets does not fall below 60 °C. Each tap and appliance should be run sequentially for at least five minutes at the full temperature.
n ‘To keep everything as straightforward as possible, the individual results are clearly laid out. In addition, they are compared with the maximum values stated in the Water Supply Regulations so that you can immediately spot potential threats’. The Water Supply (Water Quality) Regulations 2018 do not give any prescribed concentrations or values for Legionella bacteria (Schedule 1), nor is it an indicator parameter (Schedule 2) for water quality.
It’s also worth noting that the effectiveness of any antimicrobial product depends on various factors – including formulation, application, and compliance with regulations. In some cases, products may claim to be novel antimicrobial solutions, but fail to deliver the expected results, or may not have undergone rigorous testing to validate their efficacy
50 Health Estate Journal September 2023
Who to contact if you have concerns The main authority responsible for regulating water treatment products in the UK is the Drinking Water Inspectorate (DWI), which operates under the Department for Environment, Food and Rural Affairs (Defra). The DWI is responsible for regulating public water supplies. While the Inspectorate doesn’t maintain a specific register of approved water treatment products, it does regulate and set standards for the quality of drinking water supplied by water companies in England and Wales. Water treatment products
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