Licensed Granny Flat Builders in Hills District — CDC, 60m², from $140K

A standard 60m² two-bedroom turnkey granny flat in Hills District costs $140,000–$215,000 in 2026 under the SEPP (Housing) 2021 Complying Development pathway. Custom-designed builds run $190,000–$290,000. Acreage builds in Dural, Annangrove and Kenthurst cost $190,000–$300,000+ due to on-site sewage management system (OSSM) requirements, BAL construction premiums, and extended site access on rural R5 lots. The Hills Shire Council contributions vary by location: established suburbs est. $8,000–$14,000* (Hills Development CP), Box Hill growth precinct est. $12,000–$22,000* (Box Hill CP). CDC approval via private certifier takes 10–20 business days for eligible established Hills lots. BASIX, Sydney Water Section 73 (where in service area), OSSM (where outside service area), and HBCF insurance are additional fixed-cost line items.

The minimum lot size is 450m² under SEPP (Housing) 2021 for the fast Complying Development (CDC) pathway — this applies across the full Hills Shire LGA. In practice, established Hills suburbs rarely have a lot size problem: Castle Hill, Baulkham Hills, Kellyville, Glenhaven and Dural lots typically run 600m²–1,200m²; acreage lots in Annangrove and Kenthurst are 1ha–10ha+. The pressure point is Box Hill and North Kellyville growth estates, where lots of 300m²–450m² are common. Sub-450m² growth corridor lots require a DA through The Hills Shire Council under The Hills DCP 2012. Also check developer covenants on any growth estate title — some prohibit secondary dwellings regardless of lot size.

The Hills Shire Council administers multiple contributions plans — the applicable plan and rate depends on your lot location and must be confirmed via Section 10.7(2) Planning Certificate. Established suburbs (Castle Hill, Baulkham Hills, Kellyville, Glenhaven, Dural, Annangrove) fall under The Hills Development Contributions Plan — secondary dwelling contributions estimated $8,000–$14,000* (S7.11 fixed rate)*. Box Hill growth precinct falls under the Box Hill Contributions Plan — rates estimated $12,000–$22,000* per secondary dwelling*. Unlike Camden Council which uses a percentage-based S7.12 rate (0.5%/1% of build cost), The Hills primarily operates S7.11 fixed-rate plans — meaning the contribution is the same regardless of whether your build costs $160K or $260K in that precinct. Confirm which plan applies via thehills.nsw.gov.au before signing a builder contract.

Properties within the Castle Hill Heritage Conservation Area (the historic Showground Road precinct and surrounding blocks in the old Castle Hill town centre) cannot use the SEPP CDC pathway — SEPP (Housing) 2021 explicitly excludes Heritage Conservation Areas from Complying Development. A Development Application (DA) through The Hills Shire Council is required. Design must be sympathetic to the heritage context — appropriate materials, concealed siting behind the principal dwelling, compatible scale. Add $5,000–$12,000 for heritage architect or specialist input, and budget 10–18 weeks* for DA assessment. Properties near but outside the HCA boundary are unaffected. Confirm your exact heritage status via a Section 10.7(2) Planning Certificate from The Hills Shire Council before commissioning any design work. Individual heritage items also exist in Glenhaven on older farming properties — these may also affect CDC eligibility.

Yes — always. Two approval pathways exist. Pathway 1: Complying Development Certificate (CDC) — issued by a private certifier in 10–20 business days, available where the lot meets all SEPP (Housing) 2021 standards (450m²+ lot, principal dwelling exists, not heritage, BAL-29 or lower, not flood-affected, setbacks met) and satisfies The Hills DCP 2012 residential secondary dwelling provisions. Pathway 2: Development Application (DA) — lodged with The Hills Shire Council, required where any CDC standard isn't met, for Heritage Conservation Area properties, or for Box Hill/North Kellyville lots under 450m². Both pathways require a BASIX certificate, and HBCF insurance on the builder before deposit is paid. Sydney Water Section 73 is required where the lot is in the Sydney Water service area. An OSSM approval from Hills Council is additionally required where the lot is outside the service area — primarily Dural, Annangrove, Kenthurst and Middle Dural.

The northern Hills fringe — Dural, Annangrove, Round Corner, Kenthurst, Middle Dural and Glenhaven edges — is designated Bushfire Prone Land by the NSW Rural Fire Service. Properties here typically require a formal BAL assessment by a BPAD-accredited consultant ($600–$1,500) to determine the construction specification. Most lots in the Dural-Annangrove belt sit at BAL-12.5 to BAL-29; properties on steep, wooded lots closer to Cattai National Park can reach BAL-40 or BAL-FZ (Flame Zone). BAL-29 adds approximately $8,000–$15,000* to build cost. BAL-40 adds approximately $20,000–$40,000*. BAL-FZ effectively prohibits CDC and makes DA construction extremely expensive. Check the NSW Planning Portal Bushfire Prone Land map for your address before any design work — it's free and instant. Commission the formal BAL assessment before spending anything on design.

Yes — acreage Rural Residential (R5) lots in Dural, Annangrove, Kenthurst and Middle Dural almost always meet the 450m² SEPP minimum (most are 1ha–10ha+). The key differences from suburban Hills: (1) Sydney Water Section 73 often doesn't apply — many acreage lots are outside the Sydney Water service area, so an On-Site Sewage Management System (OSSM) is required ($15,000–$35,000*). Check via the Sydney Water Developer Portal Sewer Service Diagram ($15.40). (2) Bushfire BAL assessment required — most northern Hills acreage is Bushfire Prone Land. (3) Extended driveway and access to reach the rear building footprint on a 1ha lot typically adds $5,000–$20,000*. (4) Rainwater tank and pressure system may be required where mains water pressure is insufficient. Despite higher preliminaries, acreage granny flats in Dural and Annangrove achieve premium rents of approximately $550–$750/week* and are most often used for ageing parents or adult children — a strong long-term asset.

End-to-end timeline for a Hills District CDC granny flat in an established suburb is approximately 5–7 months: 2–4 weeks for site survey, BASIX and design; 10–20 business days for CDC issue by a private certifier; then 12–16 weeks for construction. For the DA pathway (Box Hill/North Kellyville sub-450m², Heritage Conservation Area, BAL-40, developer covenant), add 10–18 weeks* for Hills Shire Council DA assessment. For acreage builds in Dural and Annangrove, add 3–6 weeks for BAL assessment by an accredited consultant and OSSM design and approval — these run in parallel with design but require their own sign-off before CDC is issued. Developer covenant variation in growth estates can add another 2–6 months at the very front of the project before DA can even be lodged.

A Section 10.7(2) Planning Certificate from The Hills Shire Council costs approximately $89–$189* and takes approximately 5 business days. It is the definitive document confirming your lot's zoning (R2, R3, R5 rural-residential), heritage listing or HCA inclusion (Castle Hill HCA, Glenhaven HCA, individual items), bushfire prone land status, flood mapping (Cattai Creek, Hills Creek, local overland flow), the contributions plan that applies (Hills Development CP vs Box Hill CP), Western Sydney Airport ANEF contour designation, and any restrictive covenants registered on title. For Hills District specifically, the contributions plan identification is the critical output — the difference between a Hills Development CP contribution ($8K–$14K* established) and a Box Hill CP contribution ($12K–$22K*) is the most consequential cost variable after the build itself. Any builder quoting a Hills granny flat without sighting a current 10.7 certificate is guessing at your planning constraints and your contributions liability.

Hills District granny flat builders on Western Sydney Trades cover Castle Hill 2154, Baulkham Hills 2153, Kellyville 2155, Beaumont Hills 2155, North Kellyville 2155, Rouse Hill 2155, Bella Vista 2153, Norwest 2153, Winston Hills 2153, Glenhaven 2156, Annangrove 2156, Kenthurst 2156, Dural 2158, Middle Dural 2158, West Pennant Hills 2125, and Box Hill 2765. All builders know The Hills DCP 2012 secondary dwelling provisions, Box Hill Contributions Plan vs Hills Development CP rates, Castle Hill Heritage Conservation Area constraints, bushfire BAL requirements across the northern Hills fringe, and OSSM requirements for rural lots outside Sydney Water's service area. Submit from any suburb for a 2-business-hour match.