Legionella is a bacterium that thrives in warm water environments and can cause serious illness in humans. In Portugal, the need to specifically regulate the control of this threat led to the approval of Decree-Law 118/2019, legislation that establishes mandatory requirements for companies and public entities. This regulation marks an important milestone in protecting public health and water quality, recognising that prevention is fundamental to avoiding epidemics.
Portugal's historical context reveals occasional Legionella outbreaks that undermined public confidence in water systems. Decree-Law 118/2019 emerges to fill previous regulatory gaps, aligning Portugal with European directives and establishing a clear and demanding framework for managing Legionella risk.
Scope and Entities Covered by DL 118/2019
Decree-Law 118/2019 applies to all installations that operate water systems capable of creating water droplets, particularly those where water is maintained at temperatures between 20°C and 45°C — the optimal proliferation zone for Legionella.
Entities obligated to comply with this regulation include:
- Buildings of major public importance (hospitals, schools, train stations, airports)
- Hotel and tourism facilities with air conditioning systems
- Industrial installations with cooling towers or technical water systems
- Residential and commercial buildings with centralised hot water sanitation systems
- Sports facilities (swimming pools, changing rooms, saunas)
The legislation explicitly covers drinking water systems, cooling towers, hot water sanitation distribution systems, decorative fountains, and spas. Any installation where water may be aerosolised falls under regulatory scrutiny.
Main Obligations of Responsible Entities
Primary responsibility rests with the manager or owner of the installation, who must implement rigorous prevention measures. The fundamental obligations include:
Development of a Legionella Prevention and Control Plan (PPCL): Each obligated entity must develop a documented plan that identifies the specific risks of its installation and defines control procedures. This plan must be proportionate to the risk level of the installation.
Appointment of a Responsible Technician: The legislation requires the designation of a qualified technician responsible for implementing and supervising the PPCL. This professional must possess proven knowledge in water microbiology or hydraulic systems.
Mandatory Records and Reports: Entities must maintain detailed records of all preventive actions, cleaning, microbiological analyses, and treatments applied. These records must be available for inspection by the competent authorities.
Periodic Microbiological Analyses: Depending on the risk level, water analyses must be conducted to detect the presence of Legionella pneumophila. The frequency varies according to the type of installation and previous results.
Technical Requirements of the PPCL under the Legislation
The Legionella Prevention and Control Plan must mandatorily include:
- Detailed description of the installation (schemas, flowcharts, critical control points)
- Risk assessment adapted to specific characteristics
- Preventive maintenance procedures (cleaning, disinfection, chemical treatment)
- Acceptance criteria based on technical and microbiological parameters
- Corrective actions in the event of non-compliant results
- Staff training responsible for the systems
The responsible technician must have specific training in Legionella prevention and be capable of:
- Interpreting microbiological analyses
- Implementing appropriate treatments
- Supervising preventive maintenance
- Documenting all activities
The legislation also requires entities to keep the PPCL documentation updated, with periodic reviews (typically annual or when significant changes occur in the installation).
Penalties and Enforcement
Non-compliance with Decree-Law 118/2019 carries significant penalties. Fines vary depending on the severity of the violation:
- High fines (up to €150,000 for legal entities) for lack of PPCL or serious non-compliance
- Moderate fines for documentation failures or incomplete records
- Warnings for minor irregularities
The Directorate-General of Health (DGS) is the coordinating authority, whilst the Food and Economic Security Authority (ASAE) and municipal authorities conduct enforcement. These entities have the power to conduct inspections, require additional analyses, and impose corrective measures.
In addition to direct penalties, non-compliance may result in:
- Temporary or permanent closure of facilities
- Loss of certifications or operational licences
- Civil liability in the event of an epidemiological outbreak
Conclusion and Next Steps
Decree-Law 118/2019 establishes an exacting yet necessary standard for protecting public health. For many companies, the path to full compliance requires a detailed technical assessment and the development of a robust PPCL.
Successful implementation depends on specialised knowledge in water microbiology, systems engineering, and regulation. Engaging specialist consultants is not merely advisable — it is essential to ensure your installation fully complies with the law and, more importantly, protects the health of your users.
If you have questions about how your building or installation is covered by DL 118/2019, or if you need assistance developing or auditing a Legionella control plan, get in touch. Our team of water quality specialists can guide you through each step of the compliance process.
