Rental Yield on a Granny Flat in Western Sydney: 2025 Numbers

Granny flats are quietly the highest-yield property investment most Western Sydney owners can make on their existing land. We get asked weekly whether the numbers really stack up. They do, when done at the right price and on the right block. Here is the actual 2025 math.

The build cost benchmark

For a turn-key 60 sqm 2-bedroom granny flat in Western Sydney in 2025, expect:

• Modern Essential specification: $140,000 to $170,000
• Elite specification (stone benchtops, ducted air conditioning, premium fixtures): $170,000 to $200,000
• Premium / Master Craftsmen finishes (engineered timber floors, custom joinery, designer kitchen): $200,000 to $250,000

This includes the CDC approval, slab, structure, fitout, basic landscaping and connection to existing services. It does not include excessive site costs (rock excavation, retaining walls), Section 7.11 contributions (varies by council), or extensive landscaping.

Rental income, by suburb

Based on rental listings and market data for 2-bedroom granny flats in early to mid 2025:

• Blacktown, Mount Druitt: $440 to $500 per week
• Penrith, St Marys: $450 to $520 per week
• Marsden Park, Schofields, Box Hill: $480 to $560 per week
• The Hills Shire (Kellyville, Bella Vista, Castle Hill): $560 to $680 per week
• Parramatta, Toongabbie: $500 to $590 per week
• Liverpool, Edmondson Park: $460 to $540 per week
• Cumberland (Granville, Auburn): $480 to $560 per week
• Hornsby and surrounds: $550 to $640 per week

The yield calculation

Take an Elite-spec build at $180,000 generating $520 per week in Marsden Park:

• Gross annual rent: $27,040 (52 weeks at $520)
• Gross yield: 15.0 percent
• Less rates (proportional, typically $600 per year for the secondary dwelling)
• Less landlord insurance: $400
• Less maintenance reserve: $800
• Less agent management fee at 7.7 percent: $2,082
• Less vacancy allowance (2 weeks per year): $1,040
• Net annual income: $22,118
• Net yield: 12.3 percent

That is the kind of return you simply do not find in standalone investment property, where net yields of 3 to 5 percent are the norm in Sydney.

What can erode the yield

• Higher land costs: If you are building a granny flat on a block you just bought (rather than one you already own), include the land cost in the calculation and the yield drops sharply.
• Lower rent finishes: A bare-bones spec at $140,000 might only rent for $420 per week, putting net yield closer to 10 percent. Spec affects both build cost and rent, and they do not always move together.
• Distance from amenity: Granny flats 10 minutes from a train station rent for noticeably more than those 25 minutes away. Schools, shopping and public transport access materially affect demand.
• Tenant turnover: Higher turnover than standard houses (lease lengths often shorter), so factor 2 weeks vacancy per year.

Time on market

A well-presented 2-bedroom granny flat in Western Sydney typically rents within 14 to 21 days of listing in 2025. Demand is consistent because:

• Rental shortage continues in Western Sydney.
• Granny flats hit a price point that standard 2-bedroom apartments cannot match (you get a private entrance, no shared walls and a small garden).
• They appeal to a wide demographic: young professionals, downsizing seniors, students, separated couples sharing childcare.

Tax treatment

Granny flats follow standard investment property rules under ATO guidance, with two specific advantages from 2021 reforms:

• Capital gains tax exemption on formal granny flat arrangements with family members (parents, grandparents, dependent children) under written agreement.
• Full depreciation deductions on the structure and plant and equipment, equivalent to any other investment dwelling.

Always confirm specific tax treatment with your accountant. Rules are subject to change.

Realistic 10-year scenario

$180,000 build, $520 per week rent in Marsden Park in 2025, 3.5 percent annual rent growth, 2.5 percent capital growth on the main property:

• Year 1 net income: $22,118
• Year 5 net income (estimated): $26,200
• Year 10 net income (estimated): $31,100
• Cumulative 10-year net income: approximately $265,000
• Plus increment to main property value at sale: approximately $130,000 to $180,000
• Total 10-year return on $180,000 investment: $395,000 to $445,000

That is roughly a 220 to 250 percent return over 10 years on the granny flat investment, ignoring inflation and tax effects.

The catch

The numbers are excellent, but only if you build at the right price. Owners who overspend on a granny flat (above $230,000 for a standard 60 sqm build) do not see proportional rent uplift, and yield drops fast. Get three quotes, check the inclusions list line by line, and remember that a granny flat is an investment, not a designer home for yourself. Spec accordingly.