Storm water and runoff requirements
Examples of water runoff include rainwater collected from roof and paved areas around a, and water from emptied swimming pools.
Property owners have a statutory obligation under common law precedents and the Local Government Act 1995 to confine water runoff within their property boundaries so:
- it does not enter the building;
- it does not affect any property;
- it does not pond on the allotment; and
- it does not flow across any allotment boundary.
The most effective way is to provide catchment areas such as soakwells to disperse the rainwater collected from gutters and downpipes from roof and paved areas.
The design and construction of a drainage system must comply with the Building Code of Australia (BCA) and AS/NZS 3500.3.
Downpipes are required to be connected to the gutters and discharge stormwater to the soakwells. The distance between downpipes should not exceed 12m in accordance with BCA Part 3.1.2.
Clearances for soakwells away from buildings and boundaries
As a general guide, the setbacks for soakwells should be a minimum of the width of the soak well away from buildings and boundaries. It is not recommended to install soakwells where there are narrow clearances between buildings and boundaries as there would not be sufficient drainage area for water to be drained into the soil.
For further information in relation to storm water runoff, contact the City’s Building Services on 9439 0200 or by email at firstname.lastname@example.org.
A rainwater tank does not require a building permit provided that the tank is a small proprietary type of steel or fibre glass tank with a height not more than a standard fence height i.e 1.8m – with a capacity less than 5,000 litres. The location of the tank should be in the rear yard of a property and not be visible from the primary or secondary streets.
The base of the tank should sit on the ground or be supported by a tank stand no taller than 300mm.
For all other situations, a building permit needs to be obtained prior to installation.
Please refer to the WA Department of Health’s advice on the safe use of rainwater tanks on your property.