How to read a section 10.7 certificate for ground hazards NSW

A section 10.7 planning certificate in New South Wales tells you which planning controls and hazard overlays a council has attached to a lot, including acid sulfate soils, landslip risk, filled land and flood. It does not tell you the ground conditions. It tells you what the council thinks the hazards are, which controls apply, and what you will have to investigate before you can build. This walkthrough takes the certificate section by section and shows what each hazard entry means for footings and site work.

Order the certificate from the council for the lot, or through the NSW Planning Portal. A 10.7(2) certificate is the standard one and is usually enough for a hazard check; a 10.7(5) adds further advice the council chooses to include. Have the LEP (Local Environmental Plan) name to hand, because most of the entries point back to a clause or a map in it.

Step 1: Confirm the lot and the LEP that applies

Start at the top. Check the certificate names the correct lot and deposited plan, and note which LEP it cites, for example Wollongong LEP 2009 or Lake Macquarie LEP 2014. Every hazard entry that follows is read against that LEP and its map layers.

Gotcha: a certificate reflects the controls at the date of issue. If it is more than a few months old, the mapped extent of an overlay may have changed. Order a fresh one before you commit.

Step 2: Read the zoning and permitted uses

Find the land zone (for example R2 Low Density Residential or RU1 Primary Production) and the note on what development is permitted with or without consent. This sets whether your intended build is even allowed before ground conditions matter.

Gotcha: zoning tells you nothing about the soil. A residential zone on a floodplain still carries the flood and, often, the acid sulfate constraints in the steps below.

Step 3: Check the acid sulfate soils entry

Look for the acid sulfate soils clause, usually citing the LEP acid sulfate soils map and a class from 1 to 5. Class 1 is the most constrained, typically low-lying land where any works may disturb acid sulfate material. Class 5 covers land near, but not on, the mapped soils where certain works within a set distance still trigger assessment.

Acid sulfate soils form where iron sulfides in waterlogged sediments are exposed to air, producing sulfuric acid. In the lower Shoalhaven floodplain, managing this acidity has required repeated liming and other measures, and conventional treatments have often underperformed in the low-lying pyritic ground (Medawela and Indraratna 2024). Acidic soil and water also corrode steel and concrete, which is why foundations in these areas need extra protection (Medawela and Indraratna 2024). In the Illawarra, the acid sulfate material is tied to the finer silt and clay alluvium rather than the sands, and off-site disposal of the excavated soil is costly even after neutralising (Batchelder 2012).

Gotcha: a Class 5 entry looks minor but can still require an acid sulfate soils management plan if you excavate below a trigger level or lower the water table. Read the clause, not just the class number.

Step 4: Check the landslip or slope hazard entry

On hillside land, look for a landslip, slope instability or hazard-map entry. Councils in NSW list this because the Environmental Planning and Assessment Act requires a consent authority to consider whether a site is subject to hazards such as landslip when it decides a development application (Shirley and Ingles 2002). Most councils carry this as an environmental planning instrument with an associated hazard map (Shirley and Ingles 2002).

If the lot is mapped, expect a geotechnical risk assessment as a condition of consent, and expect footing and drainage design tailored to slope creep. Preferred construction on soil-creep sites includes founding below the moving zone and controlling surface and subsurface water (Shirley and Ingles 2002).

Gotcha: the certificate flags the hazard but never quantifies it. A mapped slope constraint is the start of an investigation, not a design.

Step 5: Check the flood and filled-land entries

Look for a flood-related development clause and any note about filled or reclaimed land. A flood entry means the council holds an adopted flood level for the lot and will control floor levels and materials. Filled land is the entry that most often changes the footing budget, because fill behaves differently to the natural profile beneath it.

Gotcha: the certificate rarely states the depth, age or compaction of any fill. Whether it is engineered or uncontrolled fill is left for you to establish, and that distinction can move the site class.

Step 6: Cross-check against the geology and soil landscape

The certificate is a planning document, not a soils document. Cross-check every hazard entry against the published geology and soil landscape maps for the area. In the Wollongong region, for example, the Bulli geological and soil landscape sheets map where the alluvial soils that carry acid sulfate risk sit relative to more competent residual ground (Batchelder 2012). Acid sulfate rock is a separate, less familiar risk: it has been reported in Hawkesbury Sandstone in a Sydney road tunnel, where sulfate growth cracked and debonded shotcrete (Hunter 2025), and in Silurian dacite cutting batters on the Federal Highway near the ACT border (Bridgement 2017).

Gotcha: an overlay can miss a hazard the geological map shows, and the reverse. Read both, and treat the acid sulfate soils check as a combined planning and geology exercise.

Step 7: Turn the entries into an investigation scope

List each hazard the certificate flags and write next to it what field work it will require. Acid sulfate soils means sampling and laboratory testing before you disturb the ground. A landslip entry means a slope stability assessment. Filled or flood-affected land means boreholes deep enough to characterise the fill and the material beneath it.

Certificate entry	What it flags	What it triggers
Acid sulfate soils, Class 1 to 5	Potential sulfide-bearing soils	Sampling, lab testing, management plan
Landslip / slope hazard	Mapped instability	Geotechnical risk assessment
Filled land	Fill of unknown depth or quality	Boreholes into and below the fill
Flood development clause	Adopted flood level applies	Floor level and materials controls

Gotcha: the certificate is silent on cost and depth. A desktop review of geology, soil landscape, bore records and mapped hazards is the cheapest way to scope the field work before you commission it.

A desktop report pulls the same geology, soil landscape, groundwater and mapped-hazard layers into one place so you can read them against the certificate. Generate a desktop report for the address before you order the site classification, or see a sample report to check what it contains.

LayeredGeo compiles geology, soils, groundwater and site data into an automated geotechnical desktop report for any address in Queensland, New South Wales, Victoria and South Australia.

Sources

• Nicholas Bridgement (2017). Managing the risks associated with acid sulfate rock in NSW road projects. Australian Geomechanics, Volume 52, Number 4 (Dec 2017). geomechanics.org.au
• Bob Batchelder (2012). Acid sulphate soils and rocks – occurrence and management in the Illawarra Region. Australian Geomechanics, Volume 47, Number 1 (Mar 2012). geomechanics.org.au
• Andrew Hunter (2025). Management of acid sulfate rock in a Sydney road tunnel. Australian Geomechanics, Volume 60, Number 1 (Mar 2025). geomechanics.org.au
• Andrew F Shirley and Owen G Ingles (2002). Building In Areas Of Landslip, Subsidence & Rockfall. Australian Geomechanics, Volume 37, Number 3 (Jun 2002). geomechanics.org.au
• Subhani Medawela and Buddhima Indraratna (2024). PRB Technology Incorporating Acidic Ground Conditions and Bio-Geochemical Clogging – A Critical Review. Australian Geomechanics, Volume 59, Number 2 (Jun 2024). geomechanics.org.au

About this article. Published by LayeredGeo and written from the published research cited in the Sources section above. It is general information about how property and ground conditions are assessed in Australia, not engineering, planning, legal or financial advice, and it is not specific to any property. Check anything that matters against the source dataset or a suitably qualified professional before you rely on it. If you spot something wrong, tell us at hello@layeredgeo.com.au and we will fix it.

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