If you’re building, subdividing or renovating on unsewered land in NSW, there’s a good chance you’ll need an on-site wastewater assessment.

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Across the South Coast, Southern Highlands, Southern Tablelands, Monaro, Greater Sydney and Blue Mountains, thousands of properties are not connected to a reticulated sewerage network and instead rely on on-site sewage management systems (OSSM) such as septic tanks, aerated wastewater treatment systems (AWTS) and other treatment systems.

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For new developments, extensions, subdivisions and changes to existing wastewater systems, councils will often require a wastewater assessment, land capability assessment or effluent disposal report before approval can be granted.

We’ve compiled some of the NSW towns, villages and rural areas where on-site wastewater systems are commonly found.

Important: sewer availability can vary between properties within the same suburb or locality. Some towns are partially sewered, while properties on larger lots or rural fringes may still rely on an OSSM system. Always confirm sewer availability for the individual property with the relevant council or water authority.

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South Coast NSW (Eurobodalla, Shoalhaven and Kiama areas)

Across the South Coast, on-site wastewater systems remain common in smaller coastal villages, rural communities and properties outside established sewerage networks.

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Localities where on-site wastewater systems are commonly found include:

• South Durras

• Mystery Bay

• Congo

• Central Tilba

• Tilba Tilba

• Akolele

• Nelligen

• Kioloa

• Bawley Point

• Termeil

• Tomerong

• Woollamia

• Wandandian

• rural areas surrounding Berry

• Foxground

• Rose Valley

• Jerrara

• Saddleback

• rural areas surrounding Jamberoo

• rural properties throughout the Kiama hinterland.

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Shoalhaven City Council regulates on-site sewage management systems across unsewered properties within the LGA, while Kiama Council also manages a significant number of OSSM systems across its rural areas.

Nelligen is also undergoing a sewerage upgrade, demonstrating why it is important to check the current servicing status of an individual property rather than relying only on the suburb name.

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Southern Highlands NSW

The Southern Highlands contains a mix of sewered towns, rural villages, acreage properties and agricultural land.

Major centres are generally serviced by reticulated sewer, but rural properties and the fringes of many villages may still require on-site wastewater management.

Areas where OSSM systems are commonly encountered include:

• Kangaloon

• Wildes Meadow

• Fitzroy Falls

• Sutton Forest

• Glenquarry

• Penrose

• Wingello

• Balmoral

• rural Yerrinbool

• rural Exeter

• rural Robertson

• rural Bundanoon

• rural Berrima

• Avoca

• Burrawang

• Manchester Square

• Werai

• High Range

• Colo Vale and surrounding rural land

For properties outside the sewer network, wastewater suitability often becomes an important part of determining whether a proposed dwelling, extension, secondary dwelling or subdivision can be supported by the site.

 

Southern Tablelands NSW

The Southern Tablelands includes a large number of small villages, rural-residential areas and agricultural properties where reticulated sewerage is unavailable.

Areas where on-site wastewater systems may commonly be required include:

• Bungonia

• Tarlo

• Windellama

• Towrang

• Marulan rural areas

• Tallong rural areas

• Collector

• Breadalbane

• Grabben Gullen

• Laggan

• Taralga rural areas

• Crookwell rural areas

• Frogmore

• Maimuru

• Milvale

• Monteagle

• Reids Flat

• Rugby

• Rye Park

• Thuddungra

• Wirrimah

• Wyangala and surrounding properties

These areas can present additional wastewater design considerations including rocky or shallow soils, steep slopes, waterways, groundwater, larger rural subdivisions and drinking water catchment requirements.

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Monaro and Snowy Monaro NSW

On-site wastewater is also an important consideration throughout the Monaro and Snowy Monaro region, particularly outside larger serviced centres.

Rural villages and localities where on-site systems may be encountered include:

• Michelago

• Bredbo

• Dalgety

• Numeralla

• rural Nimmitabel

• Jerangle

• Countegany

• Kybeyan

• Peak View

• Rock Flat

• Shannons Flat

• Yaouk

• rural areas surrounding Cooma

• rural properties surrounding Jindabyne and Berridale

Snowy Monaro Regional Council planning documents specifically recognise on-site sewage management as part of servicing smaller settlements and rural development across the region.

Cold climates, soil conditions, waterways, groundwater and environmentally sensitive locations can all influence the type and size of wastewater system that can be approved.

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Blue Mountains NSW

Although the major Blue Mountains townships are generally serviced by sewer, some outlying villages, valleys and rural properties remain reliant on on-site wastewater systems.

Key areas include:

• Megalong Valley

• Mount Wilson

• Mount Irvine

• Mount Tomah

• Bell

• Shipley Plateau

• other isolated and rural properties outside the sewer network

Blue Mountains City Council has specifically identified Mount Wilson, Mount Tomah, Mount Irvine, Bell, Megalong Valley and Shipley Plateau as outlying areas outside the main sewer network, and Council continues to regulate on-site sewage systems.

Wastewater assessment can be particularly important in the Blue Mountains because of steep terrain, shallow or rocky soils, sensitive bushland and proximity to waterways.

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Greater Sydney and Western Sydney

You don’t need to travel far from metropolitan Sydney to find properties without sewer connections.

On-site wastewater systems remain particularly common across Wollondilly and the Hawkesbury, as well as other rural and semi-rural properties around the edge of Greater Sydney.

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Wollondilly

Areas where sewer is unavailable or on-site wastewater is common include:

• Menangle

• Yanderra

• Nattai

• Mount Hunter

• rural The Oaks

• rural Oakdale

• rural Picton

• rural Tahmoor

• rural Thirlmere

• rural Appin

• rural Wilton

• surrounding agricultural and rural-residential land

Wollondilly Council identifies Menangle, Yanderra, Nattai and Mount Hunter, along with larger lots on town fringes and rural and semi-rural land, as areas where reticulated sewer is unavailable. The Council area has more than 5,000 on-site sewage management systems.

Wastewater reports can also attract additional requirements where properties fall within the Sydney Drinking Water Catchment.

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Hawkesbury

The Hawkesbury contains one of Greater Sydney’s largest concentrations of rural and semi-rural properties relying on private wastewater systems.

Areas where OSSM systems are common include:

• Bilpin

• Kurrajong Heights

• East Kurrajong

• Colo Heights

• Upper Colo

• Lower Portland

• St Albans

• Lower Macdonald

• Upper Macdonald

• Ebenezer

• Sackville

• Tennyson

• Blaxlands Ridge

• rural Kurrajong

• rural Glossodia

• rural Pitt Town and surrounds

 

Hawkesbury City Council estimates that there are more than 9,000 on-site sewage management systems within the LGA.

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Why on-site wastewater assessments matter

If a property does not have access to reticulated sewer, Council needs to be satisfied that wastewater can be safely treated and managed within the property.

Depending on the development and council requirements, a professional wastewater assessment may include:

• site and soil investigation

• soil testing and land capability assessment

• calculation of expected wastewater loads

• wastewater treatment system selection

• effluent disposal or irrigation area design

• assessment of slopes and drainage

• setbacks from waterways, dams and property boundaries

• groundwater considerations

• environmental constraints

• assessment of an existing septic or AWTS system

• recommendations for upgrading or expanding an existing system

• preparation of a council-ready wastewater report.

For example, Wollondilly Council requires detailed wastewater reports in a range of circumstances and specifically requires them for certain sites within the Sydney Drinking Water Catchment, smaller effluent disposal areas and particular treatment or disposal methods.

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Building or developing on unsewered land?

If you’re planning any of the following in these areas you may need an on-site wastewater assessment before your development can be approved.

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• new home

• extension or additional bedrooms

• granny flat or secondary dwelling

• dual occupancy

• subdivision

• commercial development

• tourism or accommodation development

• change or upgrade to an existing septic system

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Southern Wastewater Consulting secures project approval by preparing council-ready wastewater assessments, land capability assessments and effluent disposal reports for unsewered properties across the South Coast, Illawarra, Southern Highlands, Southern Tablelands, Monaro, Greater Sydney and Blue Mountains.

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Planning a project on unsewered land? Contact Southern Wastewater Consulting on info@southernwastewater.com.au.