Recommendations and Regulations for Hospital Water Hygiene Management
Water Hygiene Engineering Measures & Guidance
A selection of relevant, local guidelines and recommendations for healthcare managers, water safety groups, design engineers, estate managers, operations managers and contractors, on the design, instalation, commissioning, operations and maintenance procedures necessary to minimise risk of infection by waterborne pathogens from water systems within healthcare facilities.
Department of Health: Safe Water in Healthcare Premises HTM 04–01 (2016) provides comprehensive guidance of measures to control waterborne pathogens such as Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Mycobacteria and Legionella spp.
What do Water Safety Teams Need to Know About Safe Water in Healthcare Premises HTM 04–01 and Installation of of Point-of-Use Water Filters?
HTM 04–01 provides the following guidance on Point-of-Use (POU) Filtration
“Point-of-Use (POU) Filter – a filter with a maximal pore size of 0,2 µm applied at the outlet, which removes bacteria from the water flow.”
“Where water is required to be wholesome, all non-metallic materials in contact with water should comply with the requirements of BS 6920. Many of the materials satisfactorily tested against this standard are listed by WRAS in the ‘Water Fittings and Materials Directory’ or by the DWI in their published ‘List of Approved Products’.”
“Point-of-Use Filtration. For pathogenic waterborne organisms including multi-drug-resistant strains, at a minimum, and in accordance with the organisation’s water safety plan, a risk assessment should be made in order to determine whether sterilising-grade point-of-use filters should be installed or whether taps need to be changed (see American Standard Test Method (ASTM) F838–05 – ‘Determining bacteria retention of membrane filters utilised for liquid filtration’).
During design and installation, it is necessary to ensure that:
- POU filters comply with all appropriate regulations and meet EU legislation on the preparation of foodstuffs for infants and young children;
- tap outlets have appropriate fittings for attachment of filters;
- sufficient activity space between the POU filter outlet and the basin is provided so that an effective backflow prevention air gap (AUK3) is maintained, and hands can be comfortably washed without contaminating the body of the filter;
- there is sufficient flow once a POU filter has been fitted to enable effective hand-washing;
- the POU filters are changed at the intervals specified by the manufacturer.
"In systems with high particulates, a prefilter may be necessary to prevent shortened lifespan due to filters clogging.“
“Point-of-use (POU) filtration should be considered and agreed by the Water Safety Group (WSG) only as an interim safeguard where:
- control measures have been ineffective,
- prior to and during engineering remedial works,
- during periods of plumbing refurbishments and maintenance works, and
- where additional protection is required for vulnerable patients.
Continuous long-term use of POU filters is not recommended, except where there is no effective alternative. The WSG should review their continued use and ensure an action plan is created and enacted to make certain they are changed at the intervals specified by the manufacturer.”
“Where POU filters are installed as a temporary measure while appropriate remedial work is carried out, they should be changed in accordance with the manufacturers’ recommendations, typically at least once a month. Once removed for whatever reason, a replacement filter should be fitted. When changing filters, it is recommended that sampling of water quality takes place at outlets identified as sentinel points before refitting a replacement filter. It is essential to ensure that – where filters are to be used – they are constructed of the appropriate materials.”
“Where POU filters are to be used, the backflow protection requirements need to be maintained in accordance with the Water Supply (Water Fittings) Regulations 1999. This may require additional backflow protection or modification of the system. In addition, sufficient activity space should be maintained to enable the outlet to be used without contaminating the filter.”
“Where POU filters are in place, follow manufacturers’ instructions for cleaning, or they should be wiped clean as part of the basin/sink cleaning protocol as agreed by the WSG.”
“Where point-of-use filters are no longer required, the outlet connection should be flushed, cleaned and disinfected to remove any accumulated biofilm.”
Action to take
Record the service start date and lifespan or end date and replace filters as recommended by the manufacturer (bacterial-retention filters should be used primarily as a temporary control measure while a permanent solution is developed, although long-term use of such filters may be needed in some healthcare applications)
According to manufacturer’s guidelines
“POU filters, where they can be fitted, may be used to provide water free of P. aeruginosa. Where fitted, regard filters primarily as a temporary control measure until a permanent solution is developed, although long-term use of such filters may be required in some healthcare applications. Where POU filters are fitted to taps, follow the manufacturer’s recommendations for renewal and replacement and note that the outer casing of a POU filter and the inner surface can become contaminated. There should be sufficient activity space once a POU filter has been fitted.”
“When replacing taps, also consider fitting taps to which a filter can be attached to the spout outlet.”
“For direct contact with augmented care patients, water of a known satisfactory quality should be used, that is, either:
- water where testing has shown absence of Pseudomonas aeruginosa; or
- water supplied through POU filters; or
- sterile water (for example, skin contact for babies in neonatal intensive care units)."
“Chilled water and ice-making machines should not be installed in augmented care units. Where ice is needed for treatment purposes, it should be made using water obtained through a microbiological POU filter or boiled water in sterile ice trays or ice bags.”
“All taps that are used infrequently on augmented care units should be flushed regularly (at least daily in the morning for one minute). If the outlet is fittted with a POU filter, the filter should not be removed in order to flush the tap unless the manufacturer’s instructions advise otherwise.”
“If POU filters are fitted to taps, the same cleaning regime applies to the wash-hand basin, but the filter itself should be cleaned according to the manufacturer’s instructions. Care should be taken to avoid contamination to the external surface and outlet of the filter.”
HSE’s L8 document is aimed at dutyholders (e.g. employers, building owners, health & safety mangers) to support them in complying with their legal duties regarding Legionella through identifying and assessing risk, preparing a plan to prevent or mitigate risk, implementing, managing and monitoring control measures, record-keeping and appointing a responsible manager.
Complementary technical guidance is provided in HSG 274 which is split into three parts:
- Part 1 – evaporative cooling systems;
- Part 2 – hot and cold water systems; and
- Part 3 – other risk systems.
What do Water Safety Teams Need to Know About HSG 274 Legionnaires’ disease – technical guidance. Part 2: The control of legionella bacteria in hot and cold water systems. Health and Safety Executive, 2014. and Installation of of Point-of-Use Water Filters?
HSG 274 provides the following guidance on Point-of-Use (POU) Filtration
“Point of use (POU) filters: a filter with a maximal pore size of 0,2 μm applied at the outlet, which removes bacteria from the water flow.”
Action to take
Record the service start date and lifespan or end date and replace filters as recommended by the manufacturer (0,2 μm membrane POU filters should be used primarily as a temporary control measure while a permanent safe engineering solution is developed, although long-term use of such filters may be needed in some healthcare situations)
According to manufacturer’s guidelines
“Dutyholders are required to prevent or control the risk from exposure to Legionella. Precautions include physical methods such as regular movement of hot and cold water in distribution pipework, regular flushing of outlets to ensure water cannot stagnate in the hot and cold water systems and POU filters. For control measures to be effective, it is essential to keep the whole system clean, as biofilms or inorganic matter such as scale can reduce the efficacy of any type of control measure significantly.”
“POU filters prevent the discharge of planktonic Legionella and other potentially pathogenic microorganisms (bacteria and parasites) from the tap and shower outlets. They should be used primarily as a temporary measure until a permanent safe engineering solution is developed, although long-term use of such filters may be needed in some healthcare situations. They may also be considered where high level of disinfection of water systems may dislodge biofilm. Where POU filters are fitted, they should be renewed and replaced according to manufacturer’s recommendations.”
“Special considerations for healthcare and care homes: Where considered necessary for ongoing patient management, POU filters should be used primarily as a temporary control measure while a permanent safe engineering solution is developed, although long-term use of such filters may be required in some cases.”
CIBSE TM13 provides the following guidance on Point-of-Use (POU) Filtration
“Where users are at especial risk ... and where conventional regimes are not successful, disposable terminal fittings incorporating WRAS-approved membrane filters have been used successfully to prevent Legionella being discharged from the system....The particular benefit of this technique is to control risk immediately in the short term so systems can remain in use while corrective action is taken: long-term use is not recommended because it could be considered to breach the requirement to eliminate the hazard, and the ongoing cost of replacement filters.”
SHTM 04–01 Part E – Alternative materials and filtration.
SHTM 04–01 provides the following guidance on Point-of-Use (POU) Filtration
“Point-of-use filters have been found to provide protection from exposure to bacteria such as Legionella and Pseudomonas by preventing the dispersal of bacteria from showers and other water outlets. To be effective, the filter membrane needs to have a nominal pore size of no greater than 0,1μm. Before their use is contemplated, two factors should be considered:
- the filters do not eradicate the organism, but prevent discharge to the environment from the filtered outlet only;
- by retaining the organism within the pipework, it may be possible for the organisms to multiply and regressively ‘seed’ other parts of the distribution system.”
“Filters will also need to be changed routinely, depending on usage of the outlets. Their use, therefore, should be considered only as part of an overall regime of bacterial control to be used where the most vulnerable patients are to be treated. Installation of point-of-use filters should be subject to risk assessment and designers should be aware of the reduced flow that will arise from increased resistance. This could be an issue on upper floors of premises with a gravity-fed installation. Once a point-of-use filter has been installed it will require to be retained in use thereafter unless a risk assessment deems otherwise. In new or refurbished installations taps should be provided that can accommodate the later installation of point-of-use filters if the need arose.”