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What is the threshold for Legionella?

What is the threshold for Legionella?

For all water system types (except cooling towers), a measured concentration below 1 CFU/mL (1,000 CFU/L) is considered to be at the detection limit. Between 1 and 10 CFU/mL (1,000 to 10,000 CFU/L), Legionella amplification could be possible.

What level of chlorine kills Legionella?

Chlorine typically must be above 0.5 parts per million (ppm) of free chlorine in order to be effective against Legionella bacteria and other organisms in the water supply.

Which 2 guidance documents outlines the HSE guidelines for the control of Legionella?

HSE Approved Code of Practice (ACOP) L8 & HSG274

  • HSG274 Legionnaires’ disease: Technical guidance Part 1: The control of legionella bacteria in evaporative cooling systems.
  • HSG274 Legionnaires’ disease: Technical guidance Part 2: The control of legionella bacteria in hot and cold water systems.

How do I test my water for Legionella?

When a legionella testing service is called in to sample water, there are two main methods they can use: swab and bottle. Swab sampling involves collecting a surface sample with a sterile swab.

What is the law on Legionella testing?

There is a legal duty for landlords to assess and control the risk of exposure to legionella bacteria, but Health and Safety law does not require landlords to produce or obtain, nor does HSE recognise, a ‘Legionnaires testing certificate’.

Does boiling water get rid of Legionella?

Heat will kill legionella bacteria, cold will not. If you have water below 20˚C it will go into hibernation, it will not die.

Does chlorine get rid of Legionella?

Legionella grows best in warm water, like the water temperatures used in hot tubs. Warm temperatures also make it hard to keep disinfectants, such as chlorine, at the levels needed to kill germs like Legionella.

How often should taps be flushed for Legionella?

Stagnant water favours Legionella growth. To reduce the risk you should remove dead legs/dead ends in pipe-work, flush out infrequently used outlets (including showerheads and taps) at least weekly and clean and de-scale shower heads and hoses at least quarterly.