What is FHOG?

The eligibility rules

You and your partner must be Australian citizens or permanent residents
You must not have previously owned a home in Australia (either of you, anywhere)
You must live in the property as your principal place of residence for at least 6 months, starting within 12 months of settlement
The property must be a new home — never lived in, or a substantially renovated home that qualifies as new under the Act
Value cap: $650,000
No income test (this is unique to SA — federal Home Guarantee Scheme does have caps)

This is where most first home buyers get caught out:

Brand new house and land package — yes
Apartment in a newly built block — yes
Building a house on land you already own — yes (paid as reimbursement)
Buying an existing house that's been recently renovated — usually NO, unless renovation was substantial enough to qualify under the Act
Buying any established/existing home — NO

Through your lender at the same time as your loan application. Easiest path — they submit to RevenueSA on your behalf.
Direct to RevenueSA after settlement. Takes 4–6 weeks. Use if your lender didn't include it in your loan paperwork.

FHOG is just one of four major concessions available to SA first home buyers of new homes:

FHOG: $15,000 grant
Stamp duty concession (new home): $0 stamp duty up to $650,000, sliding to $700,000 (saves up to ~$29,000)
Stamp duty concession (vacant land): up to ~$15,000 saved on land valued up to $400,000
Federal Home Guarantee Scheme: 5% deposit, no LMI (saves $15,000–$25,000)

Stacked, the total benefit on a $620,000 new home in SA can reach $50,000+. Read our full SA first home buyer guide for the complete picture.

Assuming established homes qualify. They don't. New only.
Buying just over $650k. A $660,000 new house misses FHOG completely AND starts losing the stamp duty concession.
Not living in the property within 12 months. Triggers a clawback of the $15,000.
Buying jointly with someone who's previously owned property. Disqualifies the whole application.