Stormwater is rainwater that runs off surfaces such as natural ground surfaces, roads, roofs (roofwater), car parks, hardstand areas and any other thing or surface that exists.

Water that is unable to enter drainage or groundwater systems will find its way naturally to the nearest watercourse via overflow paths. These overflow paths are typically roadways, public reserves, pathways and often through private property.

 

Landowner responsibilities

  • You must maintain the stormwater pipes, gutters, downpipes, gully pits and any other components of your approved stormwater system on your property in good condition.
  • Your roof water system must comply with any Council or building certifier requirements i.e. connected to stormwater infrastructure (street channel or inter-allotment main) or approved soakage/dispersal pit.
  • If your property is downstream, you are required to accept natural overland flow from adjoining properties or public land. To put it more simply, if you are downstream, you must accept the ‘natural’ run-off onto your property.
  • If there is an easement on your property, it must be maintained and kept clear of obstructions to allow the natural flow of stormwater either to the field gully pit or other downstream point if no physical infrastructure is in place. 

 

Council’s responsibilities

  • If your property has a stormwater installation such subsoil mains, gully pits, personal access chambers and any other components of a Council owned and maintained stormwater system, Council must maintain this infrastructure to ensure its integrity of operation at all times.
  • Council may direct the property owner to connect their roof water to Council’s stormwater drainage system, if available and practical to do so.
  • Issues with overland stormwater flow between neighbouring properties are generally a civil matter to be resolved between the respective owners. Council has limited powers at this time to intervene.
  • Council’s assessment of new residential subdivisions is underpinned by the fundamental standard that ensures there is no increase or decrease in downstream or upstream flows of stormwater as a result of the development. This fundamental engineering standard is based on unimproved lots i.e. prior to dwellings being built however, there will be a reduction in stormwater flows after this due to the capture of large volumes of water during rain events on roofs and attached tanks.

 

Legal points of discharge (roof water)

There are three ways of connecting roof water to a legal point of discharge:

  1. Roof water is conveyed to the kerb and channel.
  2. An inter-allotment drainage system in accordance with Australian Standard AS/NZS 3500.3.2: 1998 (Clause 1.8).
  3. Where grade does not permit the stormwater to be piped to a system of inter-allotment or the street channel, a soakage (rubble) pit with its surface outlet being at least three (3) metres from the downstream side of building foundations and no closer than three (3) metres to any property boundary must be installed. 

 

Overland flow of stormwater

Overland flow between private properties usually occurs when:

  • the natural topography of the area is sloping
  • a site has been excavated to build a concrete slab, eg. cut and fill style construction
  • landscaping changes the topography of a property and the way it affects water on any given property.

Ideally, run-off should be promoted towards the street or to a drainage system, if provided. An upstream property owner cannot be held liable merely because surface water flows naturally from their land onto the lower land of a neighbour. 

 

Frequently asked questions

 

Pollution

It is illegal to discharge pollutants into the sewerage and stormwater drainage system, such as:

  • concrete
  • paint
  • oils
  • pesticides. 

This also means it is illegal to pour harmful chemicals down the sink.

Council officers undertake inspections of building sites and investigate all complaints concerning the discharge of pollutants into the storm water drainage system. Anyone caught discharging pollutants into the city's drainage systems will be issued with an on-the-spot fine.

Residents can also be fined for doing the wrong thing. Next time you are cleaning your paint brushes, make sure you don't let the water run into the drainage system. This also applies to oils and chemicals.