Preventing Legionnaires' disease

Published by:
Netherlands Enterprise Agency, RVO
Netherlands Enterprise Agency, RVO
Checked 13 Feb 2023
2 min read
Nederlandse versie

Do you own a business or building where there is a risk of people catching Legionnaires’ disease? You must among others make a risk analysis and possibly draw up a management plan. If too many bacteria are found, you must notify the province (for swimming and bathing water) or the Human Environment and Transport Inspectorate (ILT) (for drinking water).

Find out more or arrange now

at your municipality, province, or water authority

What is Legionella?

Legionella is a bacteria that can cause an infection of the airways called legionellosis, or Legionnaires’ disease. Legionella bacteria may grow in water with a temperature between 20 and 50 degrees Celsius, and in stagnant water. Legionella can for instance grow in tap water, swimming pools, hot tub and bath water, fountains and sprinkler water at garden centres and (car) washing machines, wastewater plants, or cooling water in wet cooling towers.

Building owners are responsible for the quality of the water. They must ensure that the health of people in contact with this water is not at risk. There are practical measures for complying with this duty of care (in Dutch).

Priority institutions

Some businesses and institutions (in Dutch) are considered priority institutions. These include:

  • hospitals
  • healthcare institutions (care homes, mental health centres, specialised care)
  • saunas
  • swimming pools and establishments with pools and showers on their premises, such as wellness centres and sex clubs
  • hotels
  • holiday parks
  • campsites
  • bed and breakfasts with more than 5 beds
  • marinas
  • petrol and service stations with shower facilities
  • prisons and cells in police stations
  • refugee centres

Risk analysis and management

Do you own a business that is considered a priority institution (see above), or does your building house such a business? These are subject to stricter regulations on primary legionellosis prevention (in Dutch). You must ask a certified company to conduct a risk analysis. If aerosols are formed you must also have drawn up a Legionella management plan of your water supply system.

A Legionella management plan describes the periodical preventive checks and the maintenance of your water supply system. This can only be done by a company with the right certification (in Dutch). Companies should comply with the latest Legionella risk and management plans (BRL 6010, in Dutch).

You must then also keep a log and perform periodic analysis on the water to find out if and how many legionella bacteria are present in the water.

How to perform water checks and when to notify

You must have your water checked at least twice a year by a certified company. If there are more than 100 colony-forming units of the bacteria per litre, you have to take action. This can include disinfection, installing filters, or closing the infected water point off.

If the standard of 1,000 colony-forming units per litre is exceeded, you must report this within 48 hours to the Human Environment and Transport Inspectorate (Inspectie Leefomgeving en Transport, ILT, in Dutch). You have to keep records of any measures you have taken and when these were taken.

Bathing water

The rules for bathing water are different. Does the bathing water contain 100 colony-forming units of Legionella per litre or more? Then you have to report this to your provincial authority as soon as possible.

Wet cooling towers

Wet cooling towers pose an extra risk to spread the Legionellabacteria, as they release droplets of water into the air. If you use a wet cooling tower for your building or work, you need to notify the Environmental Agency (Omgevingsdienst, in Dutch).

Protection of staff, guests and environment

You must indicate how you protect your staff and guests from exposure to the Legionella bacteria. You do so in your risk inventory and evaluation (RI&E). For wet cooling towers, the protection of the environment and living organisms should be included in the RI&E as well.

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