Since the NSW Low and Mid-Rise Housing reforms, more blocks across NSW can take a duplex (a dual occupancy: 2 homes on 1 lot) than before. But which rules apply to your block depends on where it is. Here is how to tell whether yours is likely to qualify.

First question: is your block in a low and mid-rise housing area?

The reforms work on 2 levels, and most of the confusion comes from mixing them up.

• Across NSW: since 1 July 2024, dual occupancies have been permitted with consent in R2 low density residential zones statewide. Your council’s own controls, including its minimum lot size, still decide whether your block qualifies.
• Inside low and mid-rise housing areas: since 28 February 2025, residential land within 800m walking distance of a nominated train or light rail station, or of a nominated town centre, in Greater Sydney, the Central Coast, the Hunter and the Illawarra has its own state standards for duplexes. Council cannot refuse a duplex on those grounds if the standards are met.

The NSW Government publishes an indicative map of these areas. Distance is measured along a walking route, not in a straight line, so confirm with council for a specific site.

The 3 numbers inside a low and mid-rise housing area

• Lot size: at least 450m².
• Width: at least 12m, measured at the front building line, not just along the kerb.
• Zone: R1, R2, R3 or R4, where dual occupancy is permitted in that zone.

The same rules allow a building height of up to 9.5m, a floor space ratio of up to 0.65:1 (about 292m² of floor area across both homes on a 450m² lot) and 1 parking space per dwelling. In R1, R2 and R3 zones, the finished duplex can usually be subdivided into 2 lots of at least 225m² and 6m wide each.

Outside those areas: council rules decide

If your block is outside a low and mid-rise housing area, the council’s local environmental plan (LEP) and development control plan set the minimum lot size, width and design rules for a duplex. These vary widely between councils, and can be higher or lower than 450m².

Where council permits dual occupancy, the Low Rise Housing Diversity Code may also allow a faster approval as complying development through a certifier. That uses the LEP minimum lot size for a duplex, or 400m² where the LEP sets none. The complying pathway is not available on heritage items or in heritage conservation areas.

Where to find the numbers

• Zoning: on the council’s planning certificate (the section 10.7 certificate) attached to the contract, and on the NSW Planning Portal spatial viewer.
• Lot size and width: on the deposited plan, not the listing. Listing figures are often rounded, and a few square metres or a few hundred millimetres of width can decide the answer.
• Low and mid-rise housing area: the indicative map on the NSW Planning website, then confirmation from council.

Where the reforms do not apply

• Excluded councils: the Blue Mountains, Hawkesbury and Wollondilly council areas.
• Hazard land: bushfire prone land and certain flood prone land.
• Heritage items: land that is or contains a listed heritage item. Heritage conservation areas are not excluded, but a design still has to respond to the character of the area.
• Transport Oriented Development areas: these have their own separate rules.
• Other exclusions: land within 200m of a high pressure dangerous goods pipeline, and certain coastal and environmentally sensitive land.

What can still stop it

Meeting the numbers gets you to the starting line. These are the things we see most often that kill a site after that:

• Restrictive covenants: a covenant on title limiting the land to 1 dwelling, common in newer estates.
• Sewer mains and easements: infrastructure running through the area the second dwelling needs.
• Flood and bushfire: mapping that excludes the site from the reforms, or adds cost and controls.
• Heritage: a listed heritage item, or conservation area controls that limit the design.
• Road widening: part of the front of the lot earmarked for acquisition.
• Stormwater: land that falls to the rear with no way to drain it without an easement over a neighbour.
• Slope: steep land that pushes build costs past the end value.

Check before you buy, not after

Every one of these can be found before exchange. A desktop screen of the title, the deposited plan and the planning certificate catches most of them in a couple of days, while walking away still costs you nothing.

Free site check: send us an address and we will screen it red, amber or green, and tell you why. Start your free site check.

General information only, current as at October 2026. Controls differ by council and change over time, so confirm the rules for a specific site with council or a town planner before relying on them.