What happens if the couple does not sell the HDB flat—will HDB find out?

HDB will know, and it is not advisable to keep quiet and keep both flats.

Key points for your situation (each spouse owns an HDB, then they marry):

- Under HDB rules, a married couple is treated as one family unit and can only own one HDB flat between them.
- After marriage, they are required to dispose of one flat, usually within a stipulated period (commonly 6 months) once HDB is notified of their marriage or discovers the dual ownership.
- HDB can find out through:
- NRIC and address records
- Marriage registration records
- CPF housing usage records
- Routine checks and when you apply for any HDB-related dealings (e.g. resale, upgrading, grants, refinancing).

If they deliberately do not sell and continue to hold two HDBs as a married couple, they risk:

- Being directed by HDB to dispose of one flat
- Possible penalties, including revocation of approvals, loss of subsidies/benefits and, in serious cases, compulsory acquisition or enforcement action.

If you are in this position, the safe approach is to:

- Decide early which HDB to keep
- Check both flats’ Minimum Occupation Periods
- Approach HDB or a solicitor to structure the sale/transfer properly.