Water safety

In developed countries like the UK and Ireland, where there is ready access to clean and safe drinking water, public health water safety issues are predominantly caused by the presence of microbiological organisms and the relationship this has with the built environment and end users.

“The core water safety issues are all related around the risk of contamination such as bacterial or chemical,” says Dennis Coates, Master Plumber, FCIPHE, from DC Plumbing. “This is often caused by incorrectly installed appliances and fittings, but could also simply be due to issues such as stagnation from outlets not being used on a water system.”

Mitigating the risks

To minimise the risk of drinking unsafe water to public health, it’s vital that there are processes in place to prevent contamination, such as a multiple-barrier approach, to ensure safety if one measure fails.

“From a public health and safety perspective, in relation to microbiological risk, there are several ways to reduce the risk, usually by controlling exposure risk or by managing the environment to reduce proliferation of bacteria within the water environment,” says Bryan Hill, FCIPHE, director and authorising engineer (water and infection control) with WIPC Consultancy and principal engineer (water) for ISSUK&I. According to Hill, the most common risk mitigation method for reducing microbiological proliferation is to maintain the water environment in a manner that prevents growth. Regulatory guidance currently states that ensuring water is stored and distributed at certain temperatures may reduce this risk.

“There is excellent guidance and regulations in the UK on how to reduce and mitigate risks,” adds Coates. “My first go-to would always be Water Regulations and the Approved Code of Practice L8. Installation and maintenance of plumbing systems complying with these documents do a great job of reducing most risks to water systems. Installers of appliances and fittings should check whether the product has been approved under regulation 4 of the Water Regulations and ensure any installation requirements listed on the approval are considered and followed carefully.”

In addition to temperature control, chemical dosing is a secondary control option that introduces a low concentration of biocide. However, careful consideration must be taken when choosing a chemical to ensure it can be used safely with the materials of construction and the drinking water limits.

“The importance of management and governance systems cannot be understated in terms of mitigating risks,” says Hill. “The use of water safety plans and safe systems of work is paramount, including clear procedures, competence requirements, engineering requirements and incident and emergency plans.”

Public health training

Problems often arise in public health engineering due to lack of awareness and therefore the absence of knowledge of how to control the risks. As part of the overall governance arrangements for water risk, competence plays a vital part in minimising those risks.

“Any form of upskilling or training that allows an individual to understand their responsibilities and undertake their duties is welcomed, regardless of what form of upskilling that takes,” says Hill.

“Many of the courses available today are simply related to sanitation and water supply in developing economies, usually with a focus on policy-making or looking at population growth and urbanisation. The public health competence shortfall should also look at the relationship between built urban environments in developed economies and the water risk, including clinical areas.”

There are courses available that offer training in specialist water hygiene from awareness courses right up to management of complex and high-risk systems. These are often City and Guilds Accredited and also delivered by experts in the industry. There are also courses such as Water Regulations training that all work to increase awareness to installers.

“Water safety should be a core driver of apprenticeships; plumbers are often unaware how much of an impact they can have on water safety, from selecting the correct fittings and installing them correctly, to something as simple as good personal hygiene and keeping tools clean,” says Coats. “Once bacteria has entered the system it is often difficult to eradicate.”

Creating more apprenticeships in the area of public health and water safety will not only ensure public health, but create more opportunities and career paths within the industry.

Low temperature risks

Part L states that in new builds the wet heating system should be designed to provide an operating maximum flow temperature of 55°C. The provision of hot water to assets that could provide an aerosol would not normally be affected by this change unless it is a hot water storage system that used an indirect heating coil or similar from the boiler. In that instance, where the heating coil from the boiler with a flow rate of up to 55°C is used to heat up stored water in a cylinder, the stored water would be stored below the minimal required temperature you would expect from the workplace guidance.

“It would be difficult to determine if changes in the regulations will show an increase in an uptake of infection from waterborne pathogens without relevant data,” admits Hill.

For many years now, temperature has been the primary control for reducing the risk of bacteria such as Legionella. If the right conditions are provided for bacteria, such as a temperature above 20°C and below 50°C and stagnation of water, then bacteria can multiply to dangerous levels.

“Most low-temperature heating systems are unable to regularly provide temperatures above the required 50°C and could mean an increase in waterborne problems,” points out Coates. “However, if all taps and other outlets are regularly used and the system completes a thermal disinfection regularly then the risk could be minimal.”

Healthcare issues

Pseudomonas aeruginosa is a group of bacteria that commonly inhabits soil, water, and vegetation. Although this microorganism is found in the environment it usually poses no harm to humans. However, it can cause infections that are tough to treat.

“Pseudomonas aeruginosa is normally associated with closed systems, but can also be present in domestic hot and cold-water systems,” says Martin Shouler, FCIPHE, associate director at Arup. “It can prove particularly dangerous to vulnerable communities that includes immuno-suppressed and/or those who have undergone surgery.”

These bacteria can also be found amongst the normal flora in the human gut and selected out by antibiotics that are not active against it, and, therefore, there can be infection from a patient’s own flora as well as from environmental sources such as water taps and drainage assets.

“This is why particular attention has been raised for several years now within healthcare,” explains Coates. “The bacteria often find its way into water systems through several routes such as during installation and maintenance work, cleaning of outlets with a cloth that is contaminated or even something as simple as touching the outlet with unclean hands.”

Once the bacteria have entered a water system, it can be very difficult to eradicate as it is adept at tolerating a wide range of environments by forming a protective mucus, called biofilm, that adheres it to pipework’s internal surfaces, protecting it from temperature changes and even chemicals.

“Eradication is, perhaps, a strong word — the most appropriate control strategies include patient environment standards, such as handwash basin and drainage design, the removal or design of complex water fittings such as manifolds and Thermostatic mixing valves (TMVs), water quality considerations, clinical risk assessments and cleanliness,” says Hill.

There has been much debate surrounding TMVs as they can be difficult to maintain and can provide optimal temperatures for bacteria to form as they are neither hot or cold.

“In healthcare there are very high standards for the operational requirements of TMVs and if installed, commissioned and maintained correctly they are unlikely to fail,” says Coates. “However, I am in agreement that they should be removed where not deemed as absolutely essential. This should be decided by completion of an accurate scald risk assessment.”

Ideally, the use of a mechanical device to prevent scalding should only be used in specific environments, like hospitals or care homes where the end user cannot detect thermal changes in water.

“A consideration for the installation of TMVs is that they create a cold-water dead leg in the piping system through operation depending on usage,” suggests Hill. “Additionally, there is some evidence to suggest the more complex a water fitting, the higher the likelihood of biofilm establishment.”

The Health and Safety Executive’s guidance states that TMVs need to be risk assessed to determine if they are required. If they are not required then they should be removed:

“Public health engineering awareness should be mandatory for those working with plumbing systems, and a level of awareness should be required by all who may impact public health,” says Coates.

“The guidance documents for healthcare water systems, HTM 04-01 suggests that all plumbers should be WaterSafe registered and this is a great starting point.”

USEFUL RESOURCES

Members can purchase the CIPHE’s guide to assessing Legionella risk in domestic properties, and the Safe Water Guide: Scald Prevention and Legionella, for a special rate. Find the link here.

To find out more about the control of Legionella bacteria in hot and cold water systems, find the link here.

Find out about City and Guilds Water Regulations & Unvented Hot Water Systems qualifications here.

Learn about WaterSafe accreditation here.