I think it depends on what the situation is. If it is just the risk assessment for legionella that is one thing. If you are looking at the way water is used, exposure, etc., then this raises a number of other issues. For example, wet work is a common cause of occupational dermatitis. (Any good dermatologist will tell you that water is an irritant) Or are we looking at risks of drowning. More information is needed about how water is present and used in the environment with which you are concerned. Chris

For low risk premises I think certainly yes. A degree of proportionality should apply, just as it would for Fire Risk. As with all things, practitioners have a duty to recognise the extent and limits of competence.