With effect from 15 May 2017, the maximum number of unrelated occupants that may be accommodated in a property is six.

Private residential properties may be rented out to no more than six unrelated persons from Monday (May 15, 2017), according to a letter sent out to real estate agencies by the Urban Redevelopment Authority (URA) on Thursday (May 11, 2017).
The current cap is eight unrelated persons.
Existing tenancy agreements with seven or eight tenants will be allowed to run their course until May 15, 2019.

The new occupancy cap will apply after that regardless of whether the tenancy agreement expires after the implementation date, the letter stated.

The letter added that landlords must comply to the new rules or may be subjected to investigations.
The changes were passed in Parliament as part of the Planning (Amendment) Bill in February.

Previous reports have said apartments that are rented to more than six unrelated tenants will be treated as dormitories and would require URA's approval.
Find out more at URA website