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  • Regulations


System owners are responsible for ensuring that their installations do not cause an infection hazard.

System owners are responsible for ensuring that their installations do not cause an infection hazard.

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Responsibility and supervision

The enterprises themselves are responsible for ensuring that they operate in accordance with the requirements of applicable laws and regulations. This obligation includes ensuring that procedures and inspections are introduced and carried out on installations which have the potential to transmit diseases caused by legionella bacteria. The enterprises themselves have the best overview of how they can meet the requirements and how their tasks and responsibilities should be distributed internally. If an enterprise causes an injury, they are responsible externally, regardless of whether individuals within the organisation were delegated responsibility for the practical follow-up of the regulations.

The supervisory authority is responsible for overseeing the enterprises. In connection with such supervision, the authority can provide advice and guidance concerning what will be needed in order to satisfy the regulations. The supervisory duty of municipalities includes ensuring that the municipality maintains an overview of relevant enterprises, ensuring that the enterprises are familiar with the requirements they are subject to, carrying out supervision in accordance with an established plan, and ensuring that any nonconformities are followed up.

Public Health Act

Act No. 29 of 24 June 2011 on public health (Public Health Act) (Lovdata) came into force on 1 January 2012. This act supersedes Act No. 66 of 19 November 1982 on the health service in the municipalities (Municipal Health Service Act).

The Public Health Act gives municipalities, county councils and central government agencies responsibility for promoting public health. While the Municipal Health Service Act delegated the tasks directly to the health services in the municipalities, this responsibility now rests with the municipalities as such, and the principle of promoting public health in all sectors (“health in everything we do”) applies to the municipalities, county councils and central government. This means that health considerations must be integrated into decision-making processes, and the provisions are adapted to the Planning and Building Act.

The provisions concerning environmental health protection were previously set out in Chapter 4a of the Municipal Health Care Act, and have been continued in Chapter 3 of the Public Health Act with a few amendments.

Environmental health protection includes having an overview and control of the environmental factors which could have an impact on public health. Amongst other things, this includes biological, chemical, physical and social environmental factors. An example of a biological environmental factor is the occurrence of legionella bacteria. 

Municipalities are required to have an overview of the health status of the population and oversee the environmental factors, and has authority to issue orders concerning investigations, correction, suspension and coercive fines. The tasks of the municipalities within the field of environmental health can be delegated to an intermunicipal body or another municipality.

In accordance with the purpose of the law, the Ministry may also issue regulations concerning environmental health protection, including drinking water and hygienic conditions in buildings, homes, premises, installations and any form of activity. Regulations may also be issued which contain detailed provisions concerning reporting duties or an approval duty for activities which, due to their nature, could impact health or changes in such activities. More detailed rules may also be issued by the Ministry concerning the obligation to have internal control systems to ensure compliance with statutory requirements.

The Norwegian Board of Health Supervision/Board of Supervision in the counties is responsible for ensuring that municipalities promote the purpose of the health service in a prudent and appropriate manner. If the Norwegian Board of Health Supervision finds that the municipality’s provision of health services is inadequate, an order to rectify the circumstances may be issued. The Norwegian Board of Health Supervision’s competence follows from Act No. 15 of 30 March 1984 on state supervision of the health service (Lovdata).

Regulation on environmental health protection

The Regulation on environmental health protection contains a specific chapter dedicated to measures aimed at preventing legionella infection.

General information concerning the Regulation

Regulation No. 486 of 25 April 2003 on environmental health protection (Lovdata) has its legal basis in the Public Health Act and applies to private and public activities and properties whose circumstances could either directly or indirectly have an impact on health; see Section 2 of the Regulation. Enterprises and properties must be planned, built, arranged, operated and wound up in a manner that is appropriate from a health perspective, so that they do not entail a risk of harm to health or health-related inconvenience; see Section 7 of the Regulation. The Regulation does not apply to environmental conditions which arise in homes or holiday homes, unless such conditions could impact on the surroundings around the dwelling or holiday home.

The municipality must strive to promote public health and help to protect the population against factors in the environment which could adversely impact health; see Section 4 of the Regulation. On this basis, the municipality must carry out supervision to ensure compliance with the requirements under the Regulation on environmental health protection; see Section 6 of the Regulation.

The person responsible for the activity or property must ensure that internal controls are introduced and implemented to ensure compliance with the requirements of the Regulation on environmental health protection; see Section 12 of the Regulation.

The internal controls must be adapted to the nature, activities, risks and size of the enterprise insofar as is necessary in order to comply with these requirements. Many enterprises that have a duty to introduce and implement internal controls under the Regulation will also be subject to internal controls under other legislation. Examples of other legislation are Regulation No. 1127 relating to systematic health, environmental and safety activities in enterprises (the Internal Control Regulations) (Lovdata) and Regulation No. 1731 of 20 December 2002 on internal control in the social and health service (Lovdata). The municipality's supervisory obligation under Section 6 of the Regulation on environmental health protection means that the municipality must have an overview of the enterprises that carry out internal controls, and ensure that the enterprises are familiar with the requirements that apply. Furthermore, the municipality must carry out supervision of the enterprise according to a set plan and follow up to ensure that the enterprise rectifies any non-conformities within a set period of time; see the remarks to the Regulation.

Many enterprises, properties and measures, including enterprises which have cooling towers or other similar installations, have an duty to notify the municipality prior to start-up or in the event of significant expansions or alterations; see Section 14 of the Regulation. If the notification reveals circumstances that do not comply with the provisions of the Regulation for satisfactory operation from a health perspective, the municipality may require correction prior to start-up or expansion or alteration of the enterprise. The duty to give notice for enterprises with cooling towers or other similar installations is included as a preventive measure against legionellosis.

Notification in the event of the detection of legionella in facilities or installations

The duty to report cases where legionella bacteria is detected is regulated in the Regulation on environmental health protection Section 13, Notification duty. The person responsible for an enterprise or property shall provide the municipality with information about circumstances that could obviously adversely affect health. This means that the person responsible must consider whether the detection of legionella bacteria in a facility that is covered by Chapter 3a of the Regulation Requirements to prevent the spread of Legionella via aerosol (see link below) may have an impact on the health situation in the local authority.

As described in Risk mapping and preventive measures, incidental findings will not provide any information on infection risk. An incidental finding will therefore not automatically render the enterprise obliged to notify the municipality. Both the extent of the legionella occurrence in the facility and the infection potential in the event of the dispersal of infected aerosols will be important when assessing the infection risk. The detection of legionella bacteria in installations that are classified under risk category 1 should normally trigger the notification duty, similarly if Legionella pneumophila serogroup 1 is encountered. Contact the municipality for advice if there is any doubt over whether or not an occurrence of legionella bacteria should be reported.

In the event of the repeated cases of legionella bacteria being detected in cooling towers or air scrubbers which may indicate the presence of serious defects, which in turn could result in the transmission of legionella infection, the manager of the enterprise must notify the municipality under Section 11c of the Regulation. The municipality may then require the installation to be assessed by an accredited inspection body.

Notification in the event of suspected or proven cases of illness due to legionella bacteria

In the event of suspected or confirmed cases of disease resulting from legionella bacteria, specific rules apply which are observed by the health authorities. Health professionals who suspect or confirm cases of legionellosis must immediately notify the Chief Medical Officer in the municipality, who in turn must notify the county governor and the Norwegian Institute of Public Health, or alternatively notify the Norwegian Institute of Public Health directly if the Chief Medical Officer cannot be contacted. The Chief Medical Officer in the municipality determines whether or not an outbreak is suspected, and whether microbiological samples should be collected from all installations which could have caused the infection, either directly or indirectly. In addition to notification, disease cases must be reported in writing to the Chief Medical Officer in the municipality and the Norwegian Institute of Public Health for entry in the “Norwegian Surveillance System for Communicable Diseases” (MSIS).

In the event of a suspected case of legionellosis (either individual cases or an outbreak), microbiological samples must be collected from all installations that could have caused the infection, either directly or indirectly. The samples must be taken before cleaning and disinfection.

The costs attributable to sampling and analysis must be borne by the enterprise.

Enterprises that are referred to in Section 11a of the Regulation on environmental health protection must be planned, constructed, organised, operated and wound up so that the entire installation, all associated processes, and any direct and indirect impacts on these, provide a satisfactory level of protection against the dispersal of Legionella via aerosols.

The installations must be regularly inspected, and procedures must be established on the basis of a risk assessment which ensures that operation and maintenance provide a satisfactory level of protection against Legionella.

Concerning scope and requirements regarding installations and third party inspection bodies, and the notification duty:

Regulation on bathing facilities, swimming pools and saunas, etc.

The Regulation on bathing facilities, swimming pools and saunas, etc. contains specific regulations which are intended to prevent legionella infection from hot tubs.

General information concerning the Regulation

Regulation of 13 June 1996 on bathing facilities, swimming pools and saunas, etc. (the Bathing Facilities Regulation) (Lovdata) is intended to safeguard satisfactory health and hygienic conditions for users of bathing facilities, swimming pools and hot tubs, and to contribute to the prevention of accidents. The Regulation covers all bathing facilities, swimming pools and saunas, including hot tubs, which are accessible to the general public. The only exception is private facilities that are exclusively intended for use by the owner and their family.  Anyone who owns or operates a bathing facility is responsible for ensuring compliance with the provisions of the Regulation, and must ensure that an internal control system is established. The owner or operator of the facility must notify the municipality before the bathing facility is taken into use or in the event of subsequent changes.  The municipality carries out supervision to ensure compliance with the provisions of the Regulation.

Specific information concerning provisions in the Regulation relating to legionella

Key sections of the Regulation which concern legionella are reproduced below.

Section 6. Notification duty and documentation

Before bathing facilities are taken into use and in the event of changes to the operation, the owner of the facility must present a notification to the municipality with an assessment of all circumstances which could impact health, hygiene or safety for users associated with operation of the bathing facility.

In the case of hot tubs, the notification must contain information about the design and operating conditions of the hot tub, including the model/type, in accordance with Section 18.

The notification must be sent to the medical advisor for comment.

Section 8. Sanitary facilities at bathing facilities

Bathing facilities must have a satisfactory number of changing rooms, showers and toilets with washbasins, dimensioned according to the visitor capacity of the facility.

There must be sufficient hot water for showering and cleaning.

Showers must be located so that visitors pass through them before gaining access to the bathing facility. Toilets must be located so that there is easy access from the bathing facility.

Anyone who owns and/or operates a bathing facility must have procedures for cleaning and disinfection to ensure that shower and sanitation facilities are satisfactory from a health perspective. Amongst other things, the growth and dispersal of Legionella must be prevented.

Section 16. Water quality

The water in swimming pools must be hygienically satisfactory. The water must be clear, without colour and inviting to bathe in. The bottom must be clearly visible across all parts of the pool.

Requirements for water quality in swimming pools


Lowest permissible

Highest permissible


mg/l Pt











Bacterial colony count
at 37°C

per ml



Pseudomonas aeruginosa

per 100 ml




mg/l O



The concentration of amines and organic substances should be maintained at a satisfactory level in order to prevent the formation of unhygienic or unpleasant substances in the water due to the rest of the water quality.

Section 18. Requirements regarding hot tubs

All hot tubs must be designed and operated so as to avoid hygiene issues.

In the case of hot tubs which have not been assessed in advance, each individual installation must be assessed in more detail by the municipality in connection with notification; see section 6.

Other associated regulations

Act relating to control of communicable diseases

The Act of 5 August 1994 relating to control of communicable diseases (the Control of Communicable Diseases Act) (Lovdata) is intended to protect the population from infectious diseases by preventing them, and their transfer, to the general population. Regulation of 1 January 1995 on infectious diseases harmful to public health (Lovdata) defines legionellosis as an infectious disease which is harmful to public health.

All municipalities and regional health trusts are required by law to prepare their own infection control plans. The municipality and the municipal Chief Medical Officer who is responsible for infection control must perform their tasks relating to infection control as stipulated in the law. The municipality must propose a plan for the work of the health service relating to protection from infectious diseases, including preparedness plans and measures, and organise and lead this work.

The Control of Communicable Diseases Act is an empowering law which gives the municipal board the power to take a wide range of decisions, including imposing a ban on meetings, restrictions on communication, etc., when it is necessary to prevent an infectious disease or to combat transmission. The Directorate of Health has the power to take such decisions for the whole or regions of the country in the event of a serious outbreak of an infectious disease, or when it is vital to put measures in place quickly in order to prevent transmission of the disease.

The Norwegian Institute of Public Health is controller for the Norwegian Surveillance System for Communicable Diseases (MSIS) and also receives notifications of infectious diseases via its 24-hour staffed infection control service. The Norwegian Institute of Public Health has a field epidemiology group which can travel out to municipalities and assist in contact tracing.

Planning and Building Act

Technical regulations pursuant to the Planning and Building Act contain many provisions which are relevant to the prevention of Legionella infection.

Act No. 71 on planning and building (the Planning and Building Act) (Lovdata), as subsequently amended and associated technical building regulation (TEK 17) is also relevant as regards the prevention of legionella infection. In brief, it can be said that the planning and building regulations impose requirements concerning hygienic conditions relating to the moisture protection of buildings, ventilation systems, water, heating and sanitation facilities, and the operation/maintenance of technical installations. 

In accordance with Section 15-5 of the Regulation, internal water and sewage installations must be designed and installed so that good hygiene and health are safeguarded. In the guidance to TEK 17, published by the Norwegian National Office of Building Technology and Administration, the following recommendations have been issued in order to prevent the growth and spread of legionella.

  • Hot water in circulating systems should be kept at a temperature of at least 65 °C.

  • Some plastics contain nutrients for bacteria and should be avoided.

  • The plumbing system must be dimensioned so as to ensure that the water flow velocities for each pipe dimension are normal.

In accordance with Section 15-6 of the Regulation, tapping points for drinking water must not be at a temperature which could cause burn injuries. To avoid the risk of scalding, the guidance for TEK 17 recommends the following maximum temperatures at tapping points:

The water temperature for water which is to be used for personal hygiene must be adapted to the users concerned. Fittings for hot water systems for personal hygiene must have (child) safety measures which ensure that the maximum temperature during normal use does not exceed 38 °C at the point where it is tapped in buildings where users cannot be expected to regulate the temperature, e.g. nurseries, care homes, etc. For other buildings, a temperature of 55 °C applies at the tapping point.

Working Environment Act

In accordance with the Act of 17 June 2005 relating to working environment, working hours and employment protection, etc. (Lovdata), the workplace must be satisfactory in every regard based on an individual and overall assessment of the working environment factors which could have an impact on the workers’ mental and physical health and welfare; see Section 4-1.

Regulations on systematic health, environmental and safety work in enterprises, 6 December 1996 (Internal Control Regulations) (Law data) sets requirements regarding the written documentation of how the enterprise has organised its work relating to HSE and associated responsibilities and the delegation of duties. Risk assessment, action plans and procedures to detect and correct any breaches of requirements must also be documented (non-conformity reporting).


Legionellaveilederen bygger på Vannrapport 123: Forebygging av legionellasmitte – en veiledning (4. utgave 2015) skrevet av Jens Erik Pettersen.