HOW TO ADDRESS THE PROBLEM: PREVENTION, PREVENTING, AND RESOLVING LEGIONELLA. WHO IS AFFECTED? LABORATORY FOR CHEMICAL, BACTERIOLOGICAL, MICROBIOLOGICAL, AND PHYSICAL ANALYSIS

C.B.A. ANALISI srl Chimica Biologia Ambiente

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How to Address the Problem

Preventing or Resolving the Legionella Problem

Legionellosis Risk Assessment Risk analysis is the first and most important pillar of prevention. This is not merely a formal check but an in-depth investigation aimed at mapping every potential hazard within the water system to ensure user safety and compliance with current regulations.

To objectively quantify the risk, a scientific methodology based on the probability and impact matrix must be adopted. The risk level is calculated using the formula:

R = G * P

Where:

G = Severity—Extent of potential harm to health
P = Probability—Frequency or likelihood that the critical event will occur

This calculation allows us to generate a customized Risk Matrix, which serves as a guide for planning targeted and prioritized mitigation measures. The proliferation of Legionella is never random but is facilitated by specific environmental conditions. The critical points that must be examined with extreme care are:

The Temperature Range: water temperatures, with a particular focus on the critical range between 20°C and 50°C, the ideal habitat for bacterial growth.
Stagnant Water and Biofilm: rarely used or oversized pipes where stagnant water promotes the formation of biofilm, a protective layer that nourishes bacteria and shields them from disinfectants.
System Condition: age of materials, presence of corrosion or limescale buildup that can compromise the effectiveness of treatments.

Not all points in a system pose the same danger. The so-called Critical Control Points must be identified, including:

DHW Storage Tanks: The “lungs” of the domestic hot water system, often subject to thermal stratification and sediment buildup.
Dead-Legs: Blind or disused sections of piping where the absence of flow renders routine disinfection ineffective.
Distal Ends: Showerheads, aerators, and faucets—that is, the points where water is atomized and can be inhaled.

By studying the system configuration and analyzing maintenance history, a targeted monitoring strategy must be defined, focusing resources where the risk is greatest.

A thorough risk analysis not only helps avoid penalties but also allows you to:

Drastically reduce the likelihood of outbreaks.
Optimize maintenance and treatment costs.
Ensure a safe environment for employees, guests, or patients.

Analytical Monitoring Analytical monitoring is the only tool capable of confirming the effectiveness of the preventive procedures adopted. Through targeted sampling and laboratory analysis, we transform invisible risk into reliable data, allowing you to manage the system with full awareness.

The monitoring protocol must not be limited to a generic investigation but must aim for the highest scientific precision. Each sample must be taken from the key points of the water system (Critical Control Points) identified in the risk analysis, generally:

Source and Storage: Outlets of water heaters and storage tanks.
Distal Distribution: Faucets and showers in apartments or common areas.
Recommended Frequency: It is recommended to test for the presence of the bacterium annually or at least every two years, based in part on a risk assessment.

Each analysis is supported by an official accredited test report, which serves as essential documentary evidence in the event of inspections by health authorities. Laboratory results must be interpreted by comparing them with the limits defined by current guidelines and legislative decrees. If Legionella spp. exceeds 1,000 CFU/L, a review of control measures and possible remediation are required.

Upon completion of each sampling activity, you will receive technical consultation to interpret the results and, where possible, identify effective corrective actions to restore the system to safe conditions.

C.B.A. Chimica Biologia Ambiente is an accredited laboratory for the detection of Legionella in water intended for human consumption. In addition, our laboratory offers an innovative rapid test for the detection of Legionella spp., based on the detection of the bacterium’s DNA using the LAMP/PCR technique.

Remediation Measures and Prevention Strategies Once critical issues have been identified, it is essential to act promptly and precisely.

Proper management of a system involves simple yet rigorous steps. The measures we recommend include:

Systematic Flushing: Periodically run water through rarely used fixtures to prevent dangerous stagnation.
Terminal Sanitization: Mechanical cleaning and disinfection of aerators and showerheads on a quarterly basis to remove limescale and organic deposits.
Constant Temperature Control: Monitor storage tanks to ensure the temperature is maintained consistently above 60°C, thereby inhibiting bacterial growth at its source.

In the event of a positive microbiological test result, thermal shock treatment is one of the fastest emergency solutions:

Procedure: The water is heated to a temperature between 70°C and 80°C and flushed through every single faucet for a predetermined period of time.
Effectiveness: This method ensures the immediate elimination of circulating bacteria.
Safety: The procedure must be managed to prevent the risk of burns and thermal shock to piping materials.

For a thorough and lasting effect, especially where a layered biofilm is present, chemical treatments and biofilm removal are necessary:

Next-Generation Biocides, such as chlorine dioxide, monochloramine, or hydrogen peroxide.
Targeted Action: These treatments do more than just kill bacteria; they attack the biofilm matrix that acts as a shield for Legionella.
System Protection: Each chemical protocol must be calibrated to balance maximum disinfectant efficacy with material protection, preventing corrosion that could damage the water system.

Who is this for?

In addition to the hospitality sector (hotels, B&Bs, campgrounds), Italian regulations (specifically Legislative Decree 18/2023 and the 2015 Guidelines) extend the obligation to assess and manage risk to a wide range of facilities, classified as high-priority or high-risk due to the complexity of their systems or the vulnerability of their users, with the requirement to prepare a Risk Assessment Document (DVR). Here are the entities required to carry out these activities:

1. Healthcare and Social Care Facilities These are the highest-risk settings, as they house people with compromised immune systems.

Hospitals and Clinics: Both public and private.
Nursing Homes (RSA): Facilities for the elderly and long-term care centers.
Dental Clinics: Due to the use of water in dental unit circuits (dental chairs).
Rehabilitation Centers: Especially those equipped with therapeutic tubs or pools.

2. Sports and Wellness Facilities Any location where water is atomized (showers, whirlpools) represents a potential source of infection.

Gyms and Sports Centers: All locker rooms with communal showers.
Swimming Pools and Wellness Centers (SPAs): Saunas, Turkish baths, and tubs with air/water jets.
Beach resorts.
Thermal Baths: Due to the specific nature of the water and facilities.

3. Educational and Public

Schools and Daycare Centers: Especially after summer closures (stagnant water).
Universities and Campuses: Large water systems with many outlets.
Barracks and Correctional Facilities: High-traffic buildings with often outdated systems.

Facilities 4. Workplaces and the Service Sector According to Legislative Decree 81/08 (Consolidated Law on Safety), employers must protect employees’ health against biological agents.

Offices with large air-conditioning systems: Especially if equipped with cooling towers or spray humidifiers.
Company Cafeterias and Institutional Food Service Facilities: Where water is used for food preparation and cleaning.
Shopping Centers and Airports: Facilities with kilometers of piping and thousands of users.

5. Apartment Buildings With the introduction of the new drinking water directives, responsibility has been extended to residential complexes as well:

Condominium Managers: As Internal Water Distribution Managers (GIDI), they must monitor water quality from the meter to the faucets, especially where centralized hot water systems or storage tanks are present.

In summary, the Priority Categories according to Legislative Decree 18/2023 are:

Class A: Hospitals, clinics, nursing homes (high risk).
Class B: Hospitality facilities (hotels), senior living facilities.
Class C: Schools, gyms, public offices, prisons.
Class D: Train stations, airports, large commercial buildings.

Onboard

Water Analysis Furthermore, in the maritime sector, rigorous inspections are required to ensure the safety of onboard water. The water and sanitation systems on ships and boats are subject to specific risks due to temperature fluctuations, storage in tanks, and periods of seasonal layup. Periodic inspection is an essential requirement mandated by the Maritime Health Authority (USMAF) and international regulations (MLC 2006). Yachts and superyachts, cruise ships and ferries, commercial and merchant vessels, and recreational craft in general are subject to periodic inspections of onboard water.