Legionella bacteria live naturally in water. They become a problem when a building gives them warm, still water to grow in and a way to reach people as fine droplets they can breathe in.

Hotels have plenty of both. Here are the places our team looks first.

1. Rooms and Outlets That Aren't Used

Low-occupancy floors, closed wings and rarely used staff showers let water sit in pipework and warm up or cool down to the range where bacteria grow. The first shower after a quiet week is the highest-risk moment.

2. Hot Water That Isn't Hot Enough

Calorifiers, storage heaters and long return loops can hold water at lukewarm temperatures, especially at the bottom of vessels and at the far ends of the network. Widely used guidance such as the UK HSE's ACOP L8 recommends storing hot water at 60 °C and distributing it at 50 °C or above.

3. Cold Water That Isn't Cold Enough

Roof tanks and cold pipes that run near hot services or in sun-heated risers can rise above 20 °C, common in Egyptian summers. Tanks also collect sediment that shelters bacteria.

4. Dead Legs and Redundant Pipework

Renovations often leave capped branches and unused connections where water never moves. They seed the rest of the system.

5. Spa Pools, Whirlpools and Features

Warm, agitated water creates aerosols right where guests breathe. Decorative fountains, misting systems and irrigation sprays belong in the assessment too.

6. Cooling Towers

Towers release drift that can travel beyond the roof. Effective biocide treatment, drift eliminators in good condition and routine monitoring are part of any plan.

From a List of Risks to a Plan

A water management program turns these observations into something you can run and prove:

  • Risk assessment: where growth and spread could happen in your buildings.
  • Control measures and limits: temperatures, flushing of low-use outlets, disinfectant levels, cleaning.
  • Monitoring and sampling: who checks what, how often, and where results are recorded.
  • Corrective action: what happens when a result is out of range.
  • Verification and review: confirming the plan is followed and that it works.