In addition to evaporative cooling systems, hot and cold water systems and spa pools, there are a number of other risk systems, e.g. humidifiers, air washers, emergency showers, eye wash sprays, indoor ornamental fountains, aqueous tunnel washers etc that could potentially be a source for legionella bacteria growth.
Any water system is potentially a reasonably foreseeable legionella risk if it has any of these factors:
The actions you need to take with regard to other risk systems are detailed in HSG274 Part 3: Legionnaires’ disease: The control of Legionella bacteria in other risk water systems.
You will need to carry out a risk assessment as described in What you must do to decide whether further actions are needed. These systems and any others found to present a risk should be maintained in a clean state and monitored on a regular basis, where appropriate. There is also a duty to maintain records of all maintenance carried out together with monitoring results.