a house can have up to 4 self-contained units (including owner
's family).
Definition of self-contained: separate entrance (not shared), regardless kitchen or not.
For each self-contained unit, if it's rented to a family, it doesnt matter how many people there are in the family; if it's rented to unrelated people, each unit can only have up to 2 unrelated individuals, and the self-restriction rule applies, meaning if something is missing and there's no sign of breakin etc, the loss is not covered.
the Surcharge is usually:
10% more for 1 rental unit;
20-30% more for 2 rental units;
50% more for 3 rental units,
but it varies by different insurance company.