Yes. Your complaint is absolutely legitimate. The occupants above you are causing a nuisance to you.
Nuisance is covered under [s153] of the Strata Schemes Management Act. It may also be covered in your by-laws.
I would write to the Committee and the Strata Manager and outline your concerns. Mention [s153] and any relevant by-laws. Also mention that you have tried to reason with the occupants causing the nuisance but that this has not been successful. The onus will then be on the Committee and the Strata Manager to handle your complaint and sort out your problem.
If your scheme does not yet have a by-law about nuisance water then I would encourage you to suggest to the Committee that they undertake the proper process to create a by-law on this topic.
Examples of conditions may be: all pot plants on balconies must have a saucer and plants must not be over watered, no air conditioner condensate is to drip on balconies below, no hosing of balconies or balustrades – with only damp mops and damp cloths to be used for cleaning of balconies and balustrades, children’s water play activities etc are not to be drained onto balconies below.
STRATA SCHEMES MANAGEMENT ACT 2015 – SECT 153
Owners, occupiers and other persons not to create nuisance
153 Owners, occupiers and other persons not to create nuisance
(1) An owner, mortgagee or covenant chargee in possession, tenant or occupier of a lot in a strata scheme must not:
(a) use or enjoy the lot, or permit the lot to be used or enjoyed, in a manner or for a purpose that causes a nuisance or hazard to the occupier of any other lot (whether that person is an owner or not), or
(b) use or enjoy the common property in a manner or for a purpose that interferes unreasonably with the use or enjoyment of the common property by the occupier of any other lot (whether that person is an owner or not) or by any other person entitled to the use and enjoyment of the common property, or
(c) use or enjoy the common property in a manner or for a purpose that interferes unreasonably with the use or enjoyment of any other lot by the occupier of the lot (whether that person is an owner or not) or by any other person entitled to the use and enjoyment of the lot.
<small><b>Note : </b>Depending on the circumstances in which it occurs, the penetration of smoke from smoking into a lot or common property may cause a nuisance or hazard and may interfere unreasonably with the use or enjoyment of the common property or another lot.</small>
(2) This section does not operate to prevent the due exercise of rights conferred on a developer by the operation of section 82 of the Strata Schemes Development Act 2015
Note : Division 1 of Part 6 contains provisions about the circumstances in which owners of lots may carry out work that affects common property.