Just in case anyone else is still confused, the general rule of thumb is that anything that is in lot property (ie your airspace or even walls that are not considered common property such as non-supporting entirely internal walls) is the responsibility of the lot owner and anything that is in common property (including balcony airspace where the balcony is common property) is the owners corp responsibility.
What has confused this issue is that the strata manager and the lot owner are in agreement that the balcony is lot property (even though the adjoining wall is not). This means that any part of the water supply that extends beyond the wall – such as taps – is lot property.
Are we all clear on that?
And yes, there are exceptions, such as intercom devices and door closers, but there are very specific reasons for this – which is why they are called “exceptions”.