Minimum land size to build a duplex in Wollongong

The honest answer

“What is the minimum lot size for a duplex in Wollongong?” is the first question I get, and it is the wrong question — not because it is unimportant, but because Wollongong does not answer it with a number.

Most NSW local environmental plans carry a clause 4.1 table of minimum subdivision lot sizes by zone. Wollongong's does not. Clause 4.1 of the Wollongong Local Environmental Plan 2009 is map-based:

So the minimum is specific to your land, published as a mapped figure rather than a zone-wide table, and it applies to subdivision — which is a different question from whether you can build two dwellings on the lot as it stands. Conflating those two is the single most common mistake I see in duplex feasibility.

There are four tests, and they are applied in this order.

Test 1: is a dual occupancy permitted in the zone at all?

Before area, before width, before anything else. In the Wollongong LEP 2009 land use tables, “Dual occupancies” is listed as permitted with consent in Zone R1 General Residential, Zone R2 Low Density Residential and Zone R3 Medium Density Residential. It is not listed in Zone R4 High Density Residential, Zone R5 Large Lot Residential or Zone C4 Environmental Living.

That last one surprises people. An environmental living block on the escarpment foothills can look and feel like a residential street and still not carry dual occupancy as a permissible use under the local plan.

There is also a State-wide source of permission. Chapter 6 of the State Environmental Planning Policy (Housing) 2021 provides at s 166 that dual occupancies and semi-detached dwellings are permitted with consent in Zone R2 on land to which the chapter applies. The chapter applies across NSW except on bush fire prone land, coastal vulnerability and coastal wetlands and littoral rainforest areas, heritage item land, certain flood-prone land, land within 200 m of a relevant pipeline, and in four named LGAs — Bathurst Regional, Blue Mountains, Hawkesbury and Wollondilly. Wollongong is not excluded as an LGA, but the bushfire and coastal exclusions are lot-specific and common here.

Test 2: what does the Lot Size Map say about this land?

This is the number people are actually looking for, and it is only available lot by lot. You read it from the Lot Size Map published with the Wollongong LEP on the NSW Planning Portal, alongside the Land Zoning Map and the Height of Buildings Map.

Clause 4.1 has four qualifications that matter for a duplex:

• cl 4.1(4)(a) — the clause does not apply to a subdivision by registration of a strata plan or strata plan of subdivision under the Strata Schemes Development Act 2015, nor to community title subdivision. Strata is a different pathway with different standards.
• cl 4.1(4A) — for a battle-axe or access-handle lot, the area of the access handle is not included when measuring the lot.
• cl 4.1(4B) — the clause does not apply to a subdivision for an attached or semi-detached dwelling in a residential zone.
• cl 4.1(4C) — the clause does not apply to the subdivision of land in a residential zone on which there is an existing dual occupancy or multi dwelling housing.

That last one is why the standard advice is wrong here. Across most of NSW the rule of thumb is that torrens-subdividing a duplex requires roughly twice the minimum lot size, because each new lot must itself meet the minimum. In Wollongong, cl 4.1(4C) switches cl 4.1 off for residential-zoned land that already has a dual occupancy on it. The word doing the work is existing — so a proposal that builds and subdivides at the same time does not obviously get the benefit, and it needs to be checked against the current version of the plan and with council rather than assumed. The LEP was amended as recently as January 2026.

Two related local clauses: cl 2.6(2) says consent must not be granted to subdivide land with a secondary dwelling if that would put the principal and secondary dwelling on separate lots, unless the resulting lots meet the Lot Size Map minimum; and cl 4.2A restricts the erection of dwelling houses on certain rural and environmental land.

Test 3: width and shape bind before area does

This is where most “big enough” lots fail. Area is reassuring; width is decisive.

• Wollongong DCP 2009, Chapter B1, cl 4.21.2(1) — “A minimum site width of 15 metres is required for a dual occupancy development.” Variations may be granted for irregular shaped blocks, or where the design demonstrates compliance with privacy, solar access, private open space, visual amenity, built form, car parking and landscaping.
• cl 4.21.2(2) — on a corner allotment, 15 m on one frontage and 12 m on the other.
• Codes SEPP cl 3B.8(2) — for complying development, lot width at the building line must be at least 15 m, or 12 m if the car space is accessed only from a secondary road, parallel road or lane.
• SEPP (Housing) 2021 s 168 — in a low and mid rise housing area, minimum lot width at the front building line is 12 m.
• DCP Chapter B2, §6.3(3) — a minimum 15 m lot width may be required where council determines on-street parking is needed; §6.3(4) sets a minimum residential lot depth of at least 25 m.

Also worth knowing before you fall in love with a block: cl 4.10.2(11) of Chapter B1 requires the rear dwelling of a dual occupancy to have a dedicated access corridor under the same ownership, and says a right of carriageway over the front lot will generally not be supported. That corridor consumes land you had allocated to living space, and on a narrow lot it can be the difference between two comfortable homes and two compromised ones. Chapter B1 also restricts dwelling houses on battle-axe allotments to one storey (cl 4.1.2(1)), and cl 4.13.2(1) requires dwellings — dual occupancies specifically named — to be within 60 m of a fire hydrant or to comply with AS 2419.1, with forward-in and forward-out access where a driveway exceeds 15 m.

Two more Chapter B1 points decide a lot of narrow-lot questions. The width ladder is worth knowing: a dual occupancy needs 15 m, but attached dwellings and multi dwelling housing need 18 m (cl 5.1.2) — and for those two types Chapter B1 also prohibits development on an “isolated lot” in Zones R1 and R3, requiring amalgamation with an adjoining site. Those rules sit in the chapter's section for attached and multi-dwelling development rather than the dual occupancy section, so a lot that cannot carry four townhouses may still carry two dwellings. Separately, cl 4.7 does apply to a dual occupancy, and it protects neighbouring solar access: three hours of continuous sunlight between 9am and 3pm on 21 June to adjoining living-room windows and to at least half the adjoining private open space, with shadow diagrams required for two-storey dwellings. On a tight site that often determines where the second dwelling can sit and how tall it can be.

Test 4: which approval pathway are you in?

There are three sets of numbers, and they are not interchangeable. Which one applies depends on the land and on where the lot sits.

The complying pathway. Part 3B of the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 — the Low Rise Housing Diversity Code — allows “any 1 or 2 storey dual occupancy”, attached or detached, and the conversion of an existing dwelling to a dual occupancy, as complying development on a lot in Zone RU5, R1, R2 or R3 with lawful access to a public road. A registered certifier issues the certificate against fixed standards.

The non-discretionary State pathway. Chapter 6 of SEPP (Housing) 2021 applies in a “low and mid rise housing area” — land within 800 metres walking distance of a town centre shown on the Town Centres Map, or of a public entrance to a listed rail, metro or light rail station. There, s 168 sets non-discretionary standards for dual occupancies in R1, R2, R3 or R4. “Non-discretionary” is the important word: the consent authority cannot refuse on a matter those standards already settle, and a more onerous council DCP standard does not override them. Whether your lot falls inside that 800 m area is therefore worth establishing before you spend money on a design.

The local DA pathway. Everywhere else, a development application is assessed against the LEP, the mapped height and floor space ratio controls, and the Wollongong DCP — which is where the 15 m width, the site coverage caps and the private open space rules come from.

The three sets of numbers side by side

Read the current instruments before relying on this table — every one of these numbers has been amended before and will be again.

Three lots, three answers

Illustrative only, and deliberately simplified — real lots have easements, sewers, fall, vegetation and mapped hazards that change the answer. But they show why “how many square metres do I need?” cannot be answered in one number.

1. 700 m², 17.5 m frontage, flat, sewered, Zone R2, not bush fire prone, no mapped hazard, well outside any town centre or station catchment. Width and area both clear the 15 m and 400 m² thresholds, so the complying pathway is available and the numbers are fixed rather than discretionary. Subdivision into two titles is the live question, not feasibility.
2. 520 m², 12.5 m frontage, Zone R2, sewered, within 800 m walking distance of a town centre. This lot fails the 15 m width in the code and in the DCP, so a complying certificate is not available. But if it sits in a low and mid rise housing area, s 168 needs only 12 m of width and 450 m² of area, at FSR 0.65:1 and 9.5 m — so the same block can work through a development application. That is the whole point of knowing which pathway applies.
3. 1,100 m² on the escarpment, battle-axe access, bush fire prone, with a seepage line across the middle. Generous on area, and still the hardest of the three. A battle-axe lot is excluded from the Low Rise Housing Diversity Code outright; land identified as susceptible to landslide risk in an environmental planning instrument is excluded too; and the geotechnical, bushfire and drainage work will cost more than the duplex on a flat block. Chapter B6 of the DCP applies, and a geotechnical report will be required for the majority of development on escarpment land. See the escarpment guide.

Getting two titles out of one lot

Building two dwellings and creating two titles are two approvals with two sets of standards. If the plan depends on selling one half, test the subdivision before you test the build.

Strata title

Strata is the usual route for an attached dual occupancy, and it can itself be complying development: under Part 6 of the Codes SEPP, the strata subdivision of a dual occupancy for which a complying development certificate was issued under the Low Rise Housing Diversity Code is specified development, and a combined erection-and-strata-subdivision certificate is available. The standards include lawful frontage to a public road other than a lane, no dwelling behind another except on a corner or parallel-road lot, each resulting lot at least 6 m wide at the building line, and — where no dwelling is above another — a strata area, meaning the ground floor of all dwellings, of at least 180 m². Wollongong LEP cl 4.1 does not apply to strata subdivision.

Torrens title

Torrens creates two freehold lots. Under the Subdivision Code it is available only where no part of a dwelling is above any part of another, and each resulting lot must hold one dwelling, be in Zone RU5, R1, R2 or R3, be at least 6 m wide at the building line with lawful access and frontage to a public road, and be at least the minimum size the EPI specifies for subdivision for the purpose of a dual occupancy — or 200 m² if none is specified.

Where the lot is in a low and mid rise housing area and the consent was granted or the application made on or after 28 February 2025, SEPP (Housing) s 169 supplies its own standard instead: one dwelling per lot, at least 6 m wide at the front building line, lawful access and frontage to a public road, area of at least 225 m², and not a battle-axe lot. It does not apply to strata subdivision.

And note what does not work: a secondary dwelling cannot be subdivided off at all. Section 51 of SEPP (Housing) 2021 says consent must not be granted for the subdivision of a lot on which development has been carried out under that Part. If two titles are the objective, a granny flat is the wrong instrument — this page separates the definitions.

What a duplex costs beyond the build

• Development contributions. Most of the LGA is covered by the Wollongong City-Wide Development Contributions Plan (2025), in force from 8 December 2025, which levies under s 7.12 as a percentage of the proposed cost: nil up to $100,000, 0.5% between $100,000 and $200,000, and 1% above $200,000. Inside the West Dapto Urban Release Area the West Dapto Development Contributions Plan (2025) applies instead, levying per additional lot or dwelling under s 7.11 — “subdivision, dual occupancy etc” at $96,205.96 and secondary dwellings at $42,090.10, indexed to March 2026. Those per-dwelling figures are West Dapto only.
• DA and certificate fees. DA fees come from Schedule 4 of the Environmental Planning and Assessment Regulation 2021, calculated on the estimated cost of development in fee units indexed each 1 July; the 2026/27 fee unit is $118.55. Subdivision adds 3.86 fee units plus $53 per additional lot for torrens, or $65 per additional lot for strata. There is no prescribed complying development certificate fee in the Regulation — the certifier sets it.
• Long Service Payments Levy. 0.25% of works of $250,000 or more including GST, payable before a construction certificate or complying development certificate is released.
• BASIX. Required for new homes; the published maximum fee is $80 for the first two dwellings of a multi-dwelling development plus $35 for each additional, and a $5 portal fee.
• Water and sewer. Sydney Water publishes Servicing dual occupancy and other 2-home developments specifically for this case. A Section 73 Compliance Certificate is required, and infrastructure contributions may apply under an IPART-determined method, CPI-adjusted each 1 July, via the Illawarra development servicing plans.
• Design and consultants. Survey, structural engineering, stormwater and on-site detention, BASIX, and a bushfire assessment where the land is bush fire prone.

For the wider question of what a build budget actually contains, see whether $400,000 is enough to build a house in Wollongong.

Before you buy a lot for a duplex

1. Get the Section 10.7 Planning Certificate. Zone, applicable instruments, bush fire prone land, heritage, flooding and other affecting interests. It is the cheapest document in the process.
2. Read the Lot Size Map and the Land Zoning Map for that lot, not a zone-wide summary from a blog.
3. Measure the width at the building line, and the depth. Then draw the access corridor and see what is left.
4. Establish whether the lot is in a low and mid rise housing area — within 800 m walking distance of a town centre or a listed station entrance.
5. Check the exclusion triggers: battle-axe, unsewered, an existing secondary dwelling on the lot, landslide risk identified in an EPI, coastal hazard, foreshore, heritage item or conservation area, acid sulfate soils class 1 or 2, special water catchment.
6. Find the sewer. Where the main sits and whether the connection falls to it, for both dwellings, decides a surprising amount of the layout.
7. Decide the endgame before the design. Live in both, rent both, sell one, or refinance against two titles. Each points at a different subdivision pathway and a different floor plan.
8. Confirm the current instruments with council or a town planner. The LEP was amended in January 2026 and the DCP chapter in force dates from 2016.

Requirements depend on the individual property, its zoning, the proposed development and the planning controls that apply to it, and those controls change. CKS Projects builds duplexes and dual occupancies across the Illawarra; I do every site assessment myself, 45 minutes on the block, and I would rather tell you a lot will not carry two dwellings before you buy it than after.

Related reading

Sources

Checked on 28 September 2026, reading these versions: Wollongong LEP 2009 as at 19 December 2025 — later amendments exist, including one taking effect during 2026; the Codes SEPP as at 9 August 2025; SEPP (Housing) 2021 as at 17 September 2025; and DCP Chapter B1 as in force 14 December 2016. Planning instruments are amended often, so confirm the current text before relying on any clause number or figure.

• Wollongong Local Environmental Plan 2009 (2010 EPI 76) — cl 2.6(2); cl 4.1 and subclauses (2), (3), (4), (4A), (4B), (4C); cl 4.2A; cl 4.3 and cl 4.4 (map-based); the Land Use Table entries for Zones R1, R2, R3, R4, R5 and C4; cl 5.4(9).
• NSW Planning Portal, Wollongong Local Environmental Plan 2009 maps — the Lot Size Map, Land Zoning Map and Height of Buildings Map for a specific lot.
• State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 — Part 3B Low Rise Housing Diversity Code (cll 3B.1, 3B.2, 3B.4, 3B.8, 3B.9, 3B.10, 3B.11, 3B.13, 3B.15, 3B.18, 3B.19, 3B.21–3B.24); cl 1.19 land exclusions; Part 6 Subdivision Code (cll 6.1–6.4).
• State Environmental Planning Policy (Housing) 2021 — Chapter 3 Part 1 secondary dwellings (ss 49–58, including s 51); Chapter 6 low and mid rise housing (ss 164, 166, 167, 168, 169, 172).
• Wollongong City Council, DCP 2009 Chapter B1, Residential Development (in force 14 December 2016) — cll 4.1, 4.1.2, 4.2.2, 4.3.2, 4.4.2, 4.5.2, 4.6.2, 4.10.2, 4.13.2, 4.21.2, 4.23.
• Wollongong City Council, DCP 2009 Chapter B2, Residential Subdivisions — §4 subdivision forms, §6.3 lot width and depth, §6.4 battle-axe controls, §6.6 superlots.
• Wollongong City Council, DCP 2009 Chapter B6, Development in the Illawarra Escarpment — geotechnical report requirement for escarpment development.
• Wollongong City Council, Development contributions — City-Wide Development Contributions Plan (2025) and West Dapto Development Contributions Plan (2025).
• NSW Department of Planning, Planning and development fees — the 2026/27 fee unit of $118.55 and Schedule 4 of the Environmental Planning and Assessment Regulation 2021.
• NSW Department of Planning, What is the fee for a BASIX certificate? — multi-dwelling and portal fees.
• NSW Government / Long Service Corporation, Long service levy — 0.25% on works of $250,000 or more.
• Sydney Water, Land development — Section 73 Compliance Certificate, infrastructure contributions and the Illawarra development servicing plans.

This page is general information from a builder. It is not town-planning, legal or financial advice, and the illustrative lot examples are not feasibility assessments. Whether two dwellings can be built on a particular lot, and whether it can be subdivided, depends on that lot and on the instruments as they stand when an application is made. CKS Projects is a licensed builder, not a town planner, certifier or council.