True the risk is from fine spray but all outlets should be flushed at least fortnightly otherwise dead legs become present in which legionella bacteria can proliferate – if this then spreads throughout the system it can colonise other outlets such as spray taps, hosepipes and showers. Flushing fortnightly is a control strategy to prevent legionella from breeding in the first place.
Daily flushing would be better true and if this can be achieved then great, the British Standard and HSE look for a reasonable balance though and fortnightly is considered reasonable. Slightly perversely the worst time for legionella in hoses in is winter because, in some cases, an outside tap won’t be used from September until April.
Absolutely residents should be responsible, otherwise the burden of flushing all the taps becomes ridiculous. In my opinion (from a legionella perspective) almshouses are the same as Council property where tenants are responsible, no one would consider it reasonable for the Council to visit every house weekly and flush everyones taps. On the other hand I’ve seen a few almshouses where residents can no longer access the first floor – in those cases I recommend that the charity or carers flush the upstairs outlets fortnightly to avoid potential infection.