The manufacturing site consists of a ground floor, 1st floor and roof plant room.

Site Information

The mains water supply had a fire main supply feeding from this which required backflow protection. The mains water used to supply two large water tanks.

The building had a change of use and the amount of water used was minimal. Although water temperatures were satisfactory across site – always being close to 20°C – the water system had been colonised across site with large counts of Legionella Pneumophila Sero group 1.


Disinfection and resampling was first attempted, but had no effect. A Legionella Risk review was carried out and the following remedial actions were highlighted and then carried out by DCS across site:

  • Removal of the water tanks
  • Place the hot water onto localised water heaters
  • Remove TMV’s which were required
  • Place double check valve on fire main supply
  • Remove dead legs
  • Put flushing devices into place.

Once the remedial actions had been carried out the water system was disinfected.

End result

Samples were taken and found to be satisfactory. Checks are made regularly on the water system, both for microbiological growth and to ensure the flushing systems are working correctly. Also all tasks laid out within the ACOP L8 are now carried out by DCS on this site, returning satisfactory results.

Site Photos

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