The Hills District is one of the more sought-after parts of Sydney, and the blocks reflect that. Granny flats in The Hills District tend to be built on larger, premium lots where there is plenty of room to do things properly, and owners here often want a higher-spec second dwelling to match the main house.
If you own around Castle Hill, Kellyville or Baulkham Hills, this guide covers the local picture, the approval pathway, what the Metro has done for the area and which designs suit a premium block.
The Hills Shire Council covers a broad area, from established suburbs like Castle Hill and Baulkham Hills through to the newer growth around Kellyville, Rouse Hill and Box Hill. A lot of the land here is generous, with established blocks of 700 square metres and up, and leafy streets that suit a well-placed second dwelling.
That space is a gift for a granny flat project. You can give the new home its own outlook, keep good separation from the main house, and add a covered verandah or alfresco without crowding anything. Larger blocks also make access and placement easier.
Most blocks of 450 square metres or more in a residential zone can have a granny flat approved through the Complying Development Certificate (CDC) pathway. A private certifier assesses it and it usually takes about 10 to 20 business days, rather than a full council Development Application.
Hills blocks comfortably clear the 450 square metre threshold in most cases, so the CDC route is common and the bigger land often makes setbacks easy to meet. Some sites with bushfire, heritage or environmental flags may need a DA, so confirm the specifics with a certifier. Our guide on granny flat approval in NSW covers both paths.
The Sydney Metro Northwest reshaped The Hills. Stations at Castle Hill, Kellyville, Bella Vista and Rouse Hill put quick rail in reach of suburbs that used to rely entirely on the car. That has lifted demand for the area generally, and it makes a self-contained dwelling here genuinely useful, whether for family or as a rental near a Metro station.
For owners housing older parents, the Metro connection is a real plus too. It keeps family independent and connected without needing to drive everywhere. Our piece on a granny flat for elderly parents goes into that living arrangement.
Because the homes around here are premium, owners often want their granny flat to feel that way too, with a better kitchen, a nicer bathroom and a proper outdoor area. The full 60 square metre two-bedroom designs are the natural choice on these larger blocks.
The two-bedroom Snow Gum 60 with its island bench kitchen, separate laundry and porch is a strong fit for owners wanting a higher finish. The open-plan Jacaranda 60 with a verandah suits those after a relaxed, light-filled feel. Browse the full range to compare. If you want help weighing layouts, our guide to two-bedroom granny flat designs in NSW is a good companion read.
Treat these figures as a guide, since your site and inclusions drive the final price. A complete, finished granny flat in Sydney usually lands between about $120,000 and $300,000. A base one or two-bedroom build is roughly $110,000 to $150,000, and the per square metre rate runs about $2,200 to $3,300 depending on spec.
Higher-spec finishes naturally sit towards the upper end. Worth knowing for The Hills: sandstone and rock are common in parts of the area, and that is one of Sydney's two big cost multipliers, the other being how far services have to run to the sewer. Our NSW cost guide for 2026 breaks down the extras.
We build your home in the factory over about 8 weeks, then deliver and install it on site in about 2 days. From our Bringelly factory the run up to The Hills is straightforward, and the larger blocks here usually make access and placement easy. Your yard is only really in use for the couple of install days. See how it works on our process page.
Almost always. Most established blocks in Castle Hill, Kellyville and Baulkham Hills sit well above the 450 square metre threshold for CDC, with room for a full 60 square metre home and a verandah.
Yes. The full two-bedroom designs can be specified to suit a premium home, with better kitchens, bathrooms and outdoor areas. That sits towards the upper end of the cost guide.
If you own around Castle Hill or Kellyville and want a second dwelling that matches your home, let us take a look. Visit our granny flats and studios page, then contact us for a fixed quote tailored to your block. With over 30 years building modular and transportable homes in NSW, we can help you get the spec and placement right.
Accredited & Certified
NSW Builder LicenceNo. 282297C
HIA Member591826
