COVID-19 has presented the world with unprecedented circumstances on many fronts. With many people working from home, with shops and other businesses closed, there is a significant risk that in-building water systems will have suffered water quality deterioration. Some may have become colonised with bacteria which can cause significant illnesses and even death in the more susceptible population. Other water quality deterioration may follow from stagnation in water systems and corrosion of metallic substances.

The International Water Association (IWA) organised a webinar focused on ensuring safe water in sparsely occupied buildings. The panel discussion was proposed by the IWA COVID-19 Task Force, which was established in April 2020. The Task Force is Chaired by Prof Joan Rose (University of Michigan, USA) and includes representation from many of the IWA Specialist Network Groups.  This panel discussion was chaired by Task Force member, Prof Stuart Khan from the University of New South Wales in Australia. Three panellists were: Assoc. Prof. Andrew Whelton (Purdue University, USA), Dr Susanne Lee (Leegionella Ltd., UK) and Prof Michele Prevost (Polytechnique Montréal, Canada).

Assoc. Prof Whelton described how millions of building water systems across the U.S. have experienced low to no water use. He stated that plumbing safety warnings have been issued, acute health risks exist, and illness has already occurred. Assoc. Prof. Whelton said, “because building water systems are critical to the health, security, and economic prosperity of many communities, making certain low to no use doesn’t cause waterborne disease outbreaks is critical”. His key message was that focus must be paid to operating building water systems under pandemic conditions and beyond. These include the normal business places of many people currently working from home, as well as schools and universities, many of which are largely shutdown with classes being conducted online.

Dr Lee explained that building water systems which have been stagnating pose increased risk to health from a range of hazards including, but not limited to, Legionella. All water-using and water-containing equipment must be considered, risk assessed and managed – not just the distributed water. “Whilst water systems may not seem to be high on the priority list during the COVID-19 pandemic it is important for the health and safety of patients, staff and visitors that water systems are managed safely”. Dr Lee pointed out that the at-risk within the population is currently increasing and those recovering from COVID-19 may also be at increased risk of water borne infections.

Prof. Prevost emphasised that unoccupied buildings with large numbers of showers represent at risk situations, especially if the hot water system is not operated to control Legionella. Devices connected to thermal mixing valves are prone to develop Legionella after extended stagnation. Prof. Prevost highlighted, “All buildings should conduct minimum recommissioning procedures including verifying of the conditions of operations of the hot water systems, flushing, and, if justified, disinfection. Failure to do so may increase health risks to users and result in liability”.

Furthermore, prolonged stagnation in buildings is likely to cause non-compliance issues for toxic metals such as lead and copper. Prof Prevost concluded that all buildings should conduct minimum recommissioning procedures including verifying of the conditions of operations of the hot water systems, flushing, and, if justified, disinfection. Failure to do so may increase health risks to users and result in liability.

While there has been a lot of publicity to remind building owners and managers that they need to manage water systems within buildings to prevent waterborne infection once the buildings re-open there has been little to remind them that they need to consider all potential sources of waterborne infection. High levels of Legionella and other infectious agents can be growing in every-day equipment such as the sumps of carpet washers, steam cleaners, hot tubs and the hose pipes used to fill them. Even hand held misting devices used for plants and in hairdressers to dampen down hair pose a risk of infection unless these are drained, cleaned and disinfected before being put back into use. To ensure buildings are safe they need to be risk assessed and managed before re-occupation. Currently, diverse guidance is being proposed by different nations and authorities. However, there exists a clear lack of consensus on the most appropriate way to achieve safe recommissioning or extended operation under low water use conditions.