Interesting question Kavita, in that when does a roommate become a "boarder" or "tenant"?
David gave a very comprehensive answer.
Call the town and see how they define tenant versus roommate.
In W Orange a CO is required for all new leases and sales.
You need to go to the Fire headquarters on Valley Rd and pay for the inspection ahead of time ($35 if the inspection is at least 2weeks ahead of time), and to set up the appointment.
To be in compliance - You will need to have smoke detectors on each level of the home - you will receive a form that indicates where they belong. You will also need carbon monoxide detectors within 10 feet of any bedrooms - in addtion, you need a fire extinguisher in the kitchen (no more than 10lbs) - unlike other towns, WO does not require that the extinguisher be attached to the wall.
Hope this helps