Water System and Pump Set: Legionella Risk in Condominiums

The condominium water system, with storage tanks, pressure pump sets (autoclavi), and domestic hot-water networks, can create the conditions in which legionella proliferates, a bacterium that spreads through the inhalation of contaminated aerosol. Prevention rests on the Italian national guidelines for the prevention and control of legionellosis approved by the State-Regions Conference. In common systems the manager has a role comparable to the operator of the internal water network and must organise risk assessment and maintenance.

Where the risk hides

Legionella proliferates in stagnant water at intermediate temperatures and in the presence of scale and biofilm. In a condominium the critical points are recurring and must be identified precisely.

• Storage tanks and pump sets that are rarely inspected, where water stagnates
• Dead legs or dead-end pipe sections without circulation
• Domestic hot-water networks kept at intermediate temperatures favourable to proliferation
• Cold-water and hot-water networks that are not adequately spaced apart and thermally insulated

The risk assessment

The guidelines provide that even a condominium should draw up a legionellosis risk assessment, a document that describes the system, identifies the critical points, and defines control measures. The assessment is all the more relevant when the system is centralised, old, or fitted with tanks and a pump set. On the basis of the assessment, preventive measures are scheduled and, where necessary, water samples are taken by accredited laboratories.

Prevention measures

Prevention aims to avoid stagnation and keep the system clean. The manager must ensure that the cold and hot water networks are spaced apart and insulated, that the routing is as linear as possible avoiding dead-end sections, and that tanks are easy to inspect and checked periodically. Ordinary system maintenance includes the care of pipes, tanks, water softeners, and pump sets, with cleaning and disinfection where the assessment indicates it.

The manager's responsibilities

For the common network the manager is the party who must ensure the safe operation of the water system, monitor water quality, and adopt preventive measures. The task forms part of the duty to preserve common parts set out in Article 1130 of the Italian Civil Code. Documenting the risk assessment, the maintenance work, and any sampling outcomes is essential to demonstrate the diligence adopted and to protect the owners' health.

Maintaining the pump set

The pump set ensures water pressure to the upper floors and includes pumps, a tank, and an expansion vessel. Its periodic maintenance prevents both service failures and the stagnation that favours legionella. The costs of the water system and pump set are allocated in proportion to thousandths (millesimi) under Article 1123 of the Italian Civil Code, unless the system serves units or groups of units to different extents, for example when some floors are not fed by the pump set.

Keeping assessments and deadlines in order

Legionella prevention lives on recurring documents and checks: the risk assessment, maintenance work, sampling outcomes. Management software such as AmministraPro lets you file the water system documentation and schedule check deadlines, so the manager keeps the required traceability. The features are shown at /funzioni and the plans at /prezzi.