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Whitepaper tackles legionella risk

Low occupancy rates in commercial buildings could be leading to a ticking time bomb of water quality issues according to Guardian Water Treatment. 

To help building owners take the right steps to prevent these issues, in particular legionella, the company has launched a new whitepaper – Locked down but not forgotten.

In the whitepaper, Guardian draws on its own data from over 30,000 samples taken from commercial buildings, predominantly in London, over a six-month period starting from April 2020 (when the first lockdown began).

Increased legionella risk

The data shows that positive legionella samples were up 20% compared with the previous year, with overall out of specification' Total Viable Count (TVC) results (water samples that carry unacceptable levels of microbiological contamination) risen by more than 50%. Most of the buildings involved were following manual flushing regimes - this is still not enough during a period of prolonged low occupancy.

Covering advice on how to maintain water quality and prevent legionella risk, the white paper includes practical information for responsible parties – from removing redundant pipework and increasing flushing regimes, to the use of chemical dosing to keep bacteria at bay.

Excerpt from ‘Locked Down but not forgotten'

'When buildings are at peak capacity, water systems are in constant use and harmful bacteria has little chance to take-hold. With fewer people and reduced usage, water systems can become a breeding ground for pathogens if maintenance regimes are not upheld, adjusted and in some cases increased to meet the change of usage. Manual flushing, even if carried out on a regular basis, does not replicate normal usage in a large commercial building. Water will stagnate and debris will build up in the system. Deposits such as sludge, rust or biofilm provide essential nutrients required for microbial growth, while also creating pockets for legionella and other bacteria to collect and breed.'

Low occupancy future

Home working is trend that is likely to extend well into Spring 2021 and remain a permanent fixture for many businesses, as Barclays chief executive, Jes Staley said in April 2020: 'The notion of putting 7,000 people in a building may be a thing of the past.'

To keep our commercial buildings safe and ready to open again, whether back to full capacity or not, steps must be taken now to prevent the risk of a legionella and safeguard water systems from degradation and breakdown.

To download the whitepaper for free, visit:


2 December 2020


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