With the 3 requirements in place and slow moving / stagnant water, legionella colonies can grow very fast. 100 cfu/ltr can multiply to dangerous concentration of 10000 cfu/ltr and more with 48 hours.
Legionella growth need the 3 requirements (temperature, oxygen and food). But still there are places in the installation where legionella grow fast: Tanks, plastic pipework, spa’s / wellness, stagnant water, cooling towers and large/complicated drinking water installations. Legionella contamination can only occur by breathing in aerosols (shower, cooling towers or jacuzzi) or by choking water
Water temperature plays an important role for bacteria growth in general and legionella growth specially. There is no need to make an argument whether the water temperature within the UAE or GCC area is high. So most of the cold water temperatures are between 25-45 ºC and supports an ideal water temperature situation for legionella