The December 2023 rule change (the big one)

Before December 2023, SA ancillary dwellings could only be occupied by immediate family or dependents of the main-dwelling occupants — you couldn't rent them to strangers. From December 2023 onwards, ancillary dwellings can be rented to any tenant separately from the main dwelling. This single change turned granny flats from a "family stays close" product into a pure rental-yield investment vehicle. Search demand and build volumes have both roughly tripled since.

Size and design rules

The state-wide baseline for metro Adelaide ancillary dwellings.

• Maximum habitable floor area: 70m² in metro Adelaide (some hills / rural councils allow 90m²)
• Must be self-contained: separate bathroom, kitchen, sleeping area
• Must be secondary to a primary residence on the same title
• Cannot be strata-subdivided from the main dwelling
• Minimum private open space on the lot must remain (varies by zone, typically 24m²+ per dwelling)
• Setbacks: 1m to side/rear boundaries typical; front setback matches the zone

Approval process

All granny flats in SA require both Planning Consent and Building Rules Consent, lodged through the PlanSA portal. Typical timeline is 6-12 weeks depending on council. Character or heritage areas add 4-8 weeks. Public notification is uncommon for compliant designs but may be triggered by non-standard setbacks or design deviations.

Renting your granny flat: the practical rules

Once built, treat rental separately: standard Residential Tenancies Act (SA) applies, register the bond with SATB, and disclose the tenancy arrangement to your insurer, mortgage provider, and (importantly) your tax accountant. The Australian Tax Office treats rental income from a granny flat the same as any other rental — you claim depreciation on the building and can deduct interest, rates and running costs on a floor-area apportionment.

Common compliance failures

The three most common ways SA granny flats fail council inspection or trigger post-build enforcement.

• Habitable floor area exceeds 70m² once built — often because unfinished loft or roof storage is measured as habitable at final inspection
• Private open space breach — reducing the main dwelling's courtyard below the minimum during ancillary construction
• Separate driveway required but not built — some councils require defined parking for the ancillary dwelling and refuse Certificate of Occupancy until compliant

Frequently asked questions