Frequently asked questions

Yes. Colour, taste and smell cannot tell you whether Legionella bacteria are present. They can multiply in water systems, particularly where water stagnates and temperatures favour growth. Breathing in contaminated droplets from showers or other outlets can cause Legionnaires’ disease, a potentially serious pneumonia. Water that looks clean still needs appropriate risk controls.

The specialist examines how water is stored, distributed and used, considering tanks, heaters, pipework, outlets and existing control records. Temperature, infrequently used outlets and people particularly vulnerable to infection all matter. The specialist firm assesses the system before advising on controls and recording the findings. An assessment is not simply a water sample, and sampling is not automatically necessary.

A specialist firm does the work, including the property visit, examination of the water system and assessment of its risks. The specialist also explains the findings and recommended controls. Legionella NI takes bookings for legionella risk assessments and TMV assessments; technical questions about the visit should be discussed with the specialist firm.

Legionella NI takes service bookings at a set price. Confirm the amount and the scope for the legionella risk assessment or TMV assessment you intend to book. Give details of the premises and water system so the booking suits the property, and check whether any additional testing or follow-up work would sit outside that service.

Landlords have duties to assess and control Legionella risks in rented accommodation. A straightforward domestic system may need only a simple assessment, but the person undertaking it must be competent. Describe the rental property in your enquiry, including stored water, showers, vacant periods and tenant access. A specialist can advise on the assessment appropriate to those circumstances.

There is no universal annual renewal rule for every property. Review the assessment regularly and whenever there is reason to doubt its validity, such as plumbing alterations, changed occupancy or control measures that are no longer effective. Routine monitoring may be needed more frequently than a full reassessment. The specialist can advise on a review schedule for the particular system.

No. A thermostatic mixing valve blends hot and cold water to limit outlet temperature and reduce scalding risk. A TMV assessment focuses on the valve’s condition and operation, while a legionella risk assessment considers risks across the water system. Mixing valves also need consideration within Legionella controls. Explain which valves or outlets concern you when booking a TMV assessment.

A small rental home and a commercial building with several tanks and many outlets require different amounts of time. Access to plant rooms, existing records and concealed equipment also affects the visit. Availability rests with the specialist firm, which can advise on timing once the property details and access arrangements are known.

A template helps organise information, but it cannot identify risks by itself. Whoever completes the assessment needs sufficient knowledge of Legionella, the water system and suitable controls. A specialist can evaluate temperature management, stagnation and exposure together, rather than treating the exercise as a checklist. A general building inspection does not normally cover that level of water-system assessment.

Reduced use can leave water standing in tanks, pipework and outlets, allowing conditions to change since the last assessment. Before reopening, the responsible person should review the risks and existing controls. Describe the closure period, any flushing records and the intended use in your enquiry so the specialist can advise on the relevant checks.