Geotechnical, waste water & water tanks

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This is general advice and may not apply specifically to your property. For more detailed information on your personal circumstances please contact the Rebuilding Planning Team on 9294 6999.

Geotechnical Assessments

Many properties in the Dandenong Ranges are on land subject to the Erosion Management Overlay (EMO).

These properties are likely to require a geotechnical assessment to support the planning permit application to build, construct or carry out works including vegetation removal and earthworks.

The assessment determines how to manage erosion and landslip risk through siting and design of dwellings, associated landscaping and erosion management controls. 

A geotechnical assessment must be conducted by a suitably qualified geotechnical consultant. There is more information on this important topic on the Landslip and erosion management page.

Land capability assessments (for wastewater)

If your septic tank or effluent lines were destroyed during the June 2021 storm and replacing them forms part of your planning application, then you will need the appropriate on-site domestic wastewater solution and a Land Capability Assessment (LCA) is required.

The LCA is also required for the development of un-sewered residential properties to determine the suitability of the site to sustainably manage wastewater within its boundaries and to identify any risks. 

This process identifies building and development constraints including soil types, drainage lines, land slope, proximity to waterbodies as well as other relevant landscape concerns.

This will provide landholders and their architects, designers, engineers and builders with preliminary advice and options to guide the design and siting of a house. This is important work to ensure the protection of human health and the environment.

A land capability assessment must be conducted by an appropriately qualified and experienced professional in the environmental, geotechnical, soil science and/or wastewater consulting field.

There are various wastewater systems that can be used on private property - the EPA website provides guidance on what those systems are and contact details for companies that can undertaken the work. Indicative costs for installing new wastewater systems can range from approximately $10,000 - $30,000.

When installing a wastewater treatment system there is a permit process which needs to be part of your rebuilding process - there are more details are on Council's website

Rainwater tanks and point of discharge

Water Tank Factsheet(PDF, 1MB)

You may need to apply for a planning permit and/or building permit for rainwater tanks if there are any earthworks, retaining walls or any type of building structure associated with it.

Tanks must have an overflow pipe of the same diameter as the inlet pipe. 

The outlet must be connected to a stormwater drainage system, going to the legal point of discharge. A number of older properties were not connected to their legal point of discharge which can cause erosion, potential landslip issues and environmental issues such as draining into creeks and waterways.

Your tanks must be positioned at least 500mm from any boundary, not placed over septic systems, including sand filters or within 30 metres of a watercourse.

Rainwater tanks should be professionally designed and made of non toxic, corrosion resistance material. If the water tank is close to the house it might be worth thinking about metal tanks instead of plastic as they can melt and cause issues in the event of a bushfire.

Water collected may not be suitable for drinking as it may be contaminated by the surface it was collected from. Tanks should be sealed to prevent insects, vermin and other animals entering. Unsealed tanks also pose a risk to children.