Suburb guide · 2155
Can I build a duplex or granny flat in Kellyville?
Kellyville sits in The Hills Shire Council's area under The Hills Local Environmental Plan 2019. We ran 25 real Kellyville addresses through the checker: the typical block is 643 m² with 19.7 m of frontage, 20 of the 25 could add a granny flat, and 15 could carry two separate homes today.
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The typical Kellyville block
The middle block of the 25 we checked is 643 m² with 19.7 m of street frontage. The smallest was 416 m² and the largest 863 m². Zones in the sample: R2 (19), R3 (6).
The 25 blocks we checked, by land size.
What homes sell for in postcode 2155
Median sale prices for the whole of postcode 2155, January to March 2026. These cover every suburb sharing the postcode, not Kellyville alone, and they are not a value for any one block.
- Houses: $1.81m (162 sales)
- Units and apartments: $697k (111 sales)
Source: NSW Government Rent and Sales Report (Department of Communities and Justice), sales tables by postcode, NSW Government. Updated each quarter.
A granny flat
20 of the 25 blocks we checked could take one. The Hills LEP cl 5.4(9) — the greater of 60 m² or 20% of the house’s total floor area, parking excluded. Separately, the state Housing SEPP allows a granny flat of up to 60 m² through the ten-day complying-development route on a lot of 450 m² or more with a 12 m frontage, where the land is not flood, bushfire or heritage constrained.
Dual occupancy (duplex) rules in Kellyville
15 of the 25 blocks we checked could carry two or more separate homes today.
Under The Hills Local Environmental Plan 2019 a dual occupancy needs 600 m² — this LEP sets no frontage minimum, so Council's DCP governs width.
Of the 19 ordinary R2 blocks in our sample sitting outside the Low and Mid-Rise area, 15 had the 600 m². There is no LEP frontage test to pass here, but Council's DCP still judges width, setbacks and private open space, so clearing the area alone does not settle it.
Low and Mid-Rise
None of the 25 blocks we checked fell inside the state Low and Mid-Rise area, so in this part of Kellyville the LEP minimums are what count. The boundary is a walking distance from a listed centre, so it can cut through a suburb — the checker reads which side of it your own address sits on.
What else turned up
3 of 25 were on bushfire-prone land. Any of those takes a block out of the fast-track routes and into a full DA, so it changes the answer more than the lot size does.
How we got these numbers
We took 25 real Kellyville street addresses from the NSW geocoder and ran every one through the same engine this site runs for you, reading the planning controls live. Nothing here is modelled or estimated.
It is a sample, not a census. The addresses are a spread across what the geocoder returns, so treat these as "of the 25 blocks we checked" rather than a figure for every block in Kellyville. Your own block is the only one that answers for itself — that is what the box on the right is for.
Enter the address — lot, frontage, zone, constraints and what it can carry.