LEGIONELLA FAQ

Legionella is a genus of Gram-negative bacteria that live naturally in freshwater environments and multiply in engineered water systems when temperatures are between 25 °C and 45 °C, stagnation is present and biofilm provides nutrients. The most dangerous species for humans is Legionella pneumophila serogroup 1.

Infection occurs by inhalation of contaminated water aerosols produced by showers, taps, whirlpool baths, cooling towers and humidifiers. It is not transmitted from person to person, and ingestion of contaminated water is not considered a significant route of exposure.

Legionnaires' disease presents as a severe pneumonia with high fever, dry cough, myalgia, headache and sometimes gastrointestinal symptoms. A milder flu-like form, Pontiac fever, also exists. Symptoms typically appear 2–10 days after exposure. Case fatality ranges from 5% to 15% in nosocomial settings.

Any facility with complex water systems or aerosol-generating equipment must carry out a Legionella risk assessment: hotels, B&Bs, nursing homes, hospitals, clinics, gyms, spas, pools, residential buildings with centralised water systems, industrial sites with cooling towers and air-handling units. Employers are also liable under Legislative Decree 81/2008 (Workplace Health & Safety).

Legionnaires' disease is a notifiable condition in Italy. A positive test result that is not managed can trigger business suspension, administrative fines and criminal liability for the facility manager.

The cost per sampling point typically ranges from €60 to €120, depending on the number of points, facility type and geographic location. This includes on-site sampling by a qualified technician, chain-of-custody transport to an ACCREDIA-accredited laboratory and the certified test report.

The price covers: on-site technical survey, risk-based sampling plan, sample collection with documented chain of custody, accredited laboratory analysis under UNI EN ISO 11731:2017, and a digitally signed certified test report with corrective actions where applicable.

No statutory minimum exists, but the sampling plan must be proportional to the risk profile of the system. The Italian national guidelines (State-Regions Agreement 2015) specify sampling point selection criteria by facility type. We recommend requesting a no-obligation quote so the plan reflects your actual infrastructure.

Yes. International hotel chains, property management companies and multinational EHS teams managing multiple Italian sites can access a single framework contract with consolidated invoicing, a shared compliance dashboard and a unified sampling calendar across all properties.

The primary reference is the Italian State-Regions Agreement of 7 May 2015 ("Linee guida per la prevenzione e il controllo della legionellosi"), which covers risk assessment methodology, sampling frequency, action levels and corrective actions. It is complemented by Legislative Decree 81/2008 on workplace safety, Legislative Decree 18/2023 implementing the EU Drinking Water Directive, and the UNI EN ISO 11731:2017 analytical standard.

ISS guidance defines four action bands expressed in colony-forming units per litre (CFU/L): <100 CFU/L (no action required), 100–1,000 CFU/L (investigation and corrective review), 1,000–10,000 CFU/L (immediate corrective action), >10,000 CFU/L (immediate system shutdown and remediation). Applicable thresholds may vary by facility type.

Residential buildings with centralised domestic hot-water systems serving multiple units fall within the scope of the State-Regions Agreement 2015. The condominium administrator is responsible for commissioning the risk assessment. Frequency depends on system complexity and risk level established during the assessment.

The Italian regulatory framework is consistent with ECDC ELDSNet surveillance protocol, the WHO Water Safety Plan approach and European standard EN 15975-2. ACCREDIA-accredited laboratories are recognised under EA, IAF and ILAC mutual recognition arrangements, making Italian test reports internationally valid.

The standard method is culture on BCYE selective agar (buffered charcoal yeast extract) as specified in UNI EN ISO 11731:2017. Incubation takes 7–10 days at 36 °C. Results are expressed in CFU/L. For faster preliminary results, quantitative PCR may be used as a complementary method, but culture remains the regulatory reference.

Common approaches include thermal shock (raising water temperature above 70 °C at all distal points for at least 30 minutes), hyperchlorination (shock chlorination at 20–50 mg/L), chlorine dioxide dosing, copper-silver ionisation and UV point-of-entry treatment. The choice depends on system type, colonisation level and infrastructure constraints.

A dead-leg is a section of pipework with little or no water flow, creating conditions ideal for Legionella proliferation. Mitigation requires hydraulic removal where possible or scheduled flushing at defined frequencies. Dead-legs must be identified and documented in the risk assessment.

Italian national guidance requires domestic hot-water storage at ≥60 °C and distribution reaching ≥55 °C at any point in the recirculation loop. Cold-water circuits must be maintained below 20 °C. Regular temperature monitoring at distal points is part of the operational control plan.

Hotels, apart-hotels and tourist accommodation must carry out a Legionella risk assessment, implement a documented sampling plan with defined frequency (typically at least annually for low-risk systems; quarterly or bi-annual for higher-risk systems), and maintain all records available for inspection by the local health authority (ASL).

Yes. Gyms with showers, spas, thermal pools and wellness centres are considered high-risk environments due to aerosol generation. They fall within the scope of the State-Regions Agreement 2015 and are subject to regular risk assessment and sampling.

International companies operating Italian facilities are subject to Italian law regardless of where the parent company is headquartered. We provide consolidated English-language compliance documentation, a unified contract structure and a shared digital dashboard to facilitate oversight from abroad.

A qualified field technician visits the facility, maps all water outlets and risk points (storage tanks, cooling towers, showers, taps), documents system configuration and identifies dead-legs. Samples are collected following chain-of-custody protocols and transported to the accredited laboratory within the required time window.

Standard turnaround is 7 working days from the sampling date. Expedited procedures returning results in 3–5 working days are available on request for urgent pre-reopening protocols, post-incident investigations or regulatory deadlines.

The accredited laboratory report includes: identification of the analytical method (UNI EN ISO 11731:2017), results expressed in CFU/L for each sampling point, measurement uncertainty, the laboratory's ACCREDIA accreditation number and the authorised signatory. The accompanying operational report details corrective actions graded by action level.

Yes. Reports issued by ACCREDIA-accredited laboratories under UNI EN ISO 11731:2017 are the recognised evidentiary standard in Italian health authority inspections. They are also internationally recognised under EA, IAF and ILAC mutual recognition arrangements for cross-border regulatory reporting.