Start-Up Procedures after Covid-19

Please be aware the risks of Legionella, TVC, E-coli Total Coliforms Bacteria and Pseudomonas being present in your system if your building remains empty and unused for a period of time. 

Start-up procedures for systems may need to be reconsidered before buildings can be reopened.  Consideration should be given to:

  •  Water system cleaning and disinfection
  •  Sampling
  • Water quality checks
Water analysis sample

Recommissioning of Water Systems

It is advised that you speak to GES Water to devise a plan to recommission the system to allow for a speedy and safe start-up.

If your water system has been mothballed or partially mothballed during the Corona Virus outbreak, it is vital that it is not put back into use straight away. Doing this is highly dangerous if not assessed properly and undertaken by a qualified engineer.

Cleaning and Disinfection

Before returning to use, it is advised that thorough cleaning and disinfection is completed followed by water sampling to determine whether the water system is safe, and that there is no Legionella present. If there are signs of Legionella, it needs to be controlled immediately before being returned to use.
Depending on the concentration of contamination that has built-up within the system during the mothballing period, it will have an effect on the success of the disinfection. It may be necessary, therefore, to repeat the disinfection and sampling process in order to achieve control. The levels of contamination and subsequent disinfection can only be assessed by someone with the relevant qualifications and experience.

Cooling Towers

When cooling towers, evaporative cooling systems and wet separators have not been emptied before shutdown, aerosols containing Legionella can be released into the environment if the systems are restarted without having the proper controls in place. During the weeks of the plants’ shutdown, rising spring temperatures allow these bacteria to multiply and contaminate the cooling water. Therefore, cleaning and disinfection of the systems is usually necessary to limit health risks. Again, this needs to be assessed by someone with the relevant qualifications and experience.

If GES Water can be of any assistance returning your buildings to service by carrying out system disinfections, sampling and water quality checks please do not hesitate to contact us on 0800 121 8808 or emailing us on


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