Reopening Buildings After Lockdown – Risk Assessing Your Water Quality

Advice for owners, landlords and managers of buildings which have been empty or under-occupied during lockdown to risk assess their drinking water system before they reopen for employees and visitors.

Reopening Buildings After Lockdown – Risk Assessing Your Water Quality

Drinking water systems left stagnant due to prolonged inactivity can lead to poor water quality and the growth of microorganisms such as legionella bacteria, which can be harmful to health when taps get turned on again.

It is the legal duty of those in control of premises such as offices, shops, cafes, restaurants and public buildings such as community centres, leisure centres, libraries and museums to reduce the risks of exposure to legionella bacteria and to make sure their water supplies are safe.

Those responsible for reopening buildings are advised to follow  Water UK’s guidance on recommissioning water systems. This includes advice to ‘flush’ the water system with fresh water to replace all water inside the building’s pipework and appliances.

Larger buildings, with storage tanks, showers and more complex pipework, are likely to require more extensive flushing followed by cleaning and disinfection.

Anyone with a complex plumbing system should have a competent person oversee the work.

The guidance advises employing approved plumbers registered with WaterSafe to make changes or repairs. This is because they have specific training in the Water Supply (Water Fittings) Regulations and Scottish Byelaws, to make sure they meet the strict legal requirements for installing water pipes and fittings.

Jay Saunders, Water Regulations Officer at Southern Water, delivers a message on behalf of WaterSafe to those responsible for hotels, guesthouses and B&Bs reopening in May 2021.

What simple steps can I take to help make sure water is fresh and safe?

  • Run all taps individually, starting with the tap nearest to where the water enters the building and move systematically to the most distant outlet. Run until the water is clear and feels cool to the touch.
  • Where water is stored, storage cisterns should be emptied and filled with water direct from the incoming supply, before flushing the taps.
  • Flushing should be carried out in a way which minimises aerosols (water droplets in the air) e.g. by removing showerheads prior to flushing. This reduces the risks of Legionella transmission.
  • Safety considerations should be given to those doing the flushing, including wearing appropriate PPE.
  • Ensure all appliances are thoroughly flushed through before use, using manufacturer’s instruction manuals e.g. dishwashers, water fountains
  • If the property has internal filters or water softeners, these should be checked to ensure they are working correctly, as outlined in the manufacturer’s instruction manual.
  • Testing of water systems is easy to organise.

Where can I find more information?

Download Water UK’s guidance on recovering drinking water supplies in buildings and networks after prolonged inactivity:

The CIPHE has produced guidance on mitigating the risk of building water systems post Covid-19:

For further advice on managing risks associated with Legionella visit:

What should I do if I have concerns about the quality of my building’s drinking water?

Contact your water retailer for more information. Water retailers can access specialist advice on how to support their clients and the specific issues affecting them from their designated wholesale supplier contact point.

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