We call rooms used to sleep and that are more than the septic system allows extra sleeping areas.
A sewer system may not have restrictions on the number of bedrooms, butit may also.
I would call the sewer department in your town for the answer to that - but not give the address.
I would also call the town and ask how they define bedrooms.
In my town they are trying to change the criteria to include rooms that may be called extra sleeping areas, because people are bypassing the bedroom restrictions on their septics.
Of course choosing a local real estate pro can help you save a lot of time.
(Not me, I'm on the Cape, but I can help you choose a local pro when you are ready.)
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Happy to come take a look and tell you what will and won't "fly".
There use to be a closet tax http://en.wikipedia.org/wiki/Closet
A room with at least 70 sq ft and an egress window is considered a bedroom.
Many town inspectional departments do not consider a room with out a closet a bedroom, so builder by not putting them in can provide can by pass their bed room counts
ie: Dover ma - 5 bed room septic can have as many baths as you want. We called one room a library, another a den, another an office, so my 5 bed room home was actually an 8 bed room home, how one uses them is up to them. And if they decide to add a closet it is up to them.
I am a certified appraiser as well as a real estate broker and luxury home builder.
If you decide to add lighting, an electrical inspection would be required. Some towns require you to bring an entire home to current building codes, should you make changes to electrical or interior improvements (Example: A Watertown homeowner added closets to a master bedroom and one hardwired smoke detector. The town required that the entire house be updated to the latest hardwired smoke detectors.)
If you need assistance, I'd be more than happy to come by and offer any assistance. Please give me a call at 857.209.6060. firstname.lastname@example.org
You should check with the building department to see if you'd need a permit. Their number is 781-316-3390. The fee is $20 per $1,000 of estimated cost of construction. This would be an inexpensive job, so if you did need a permit the application cost would not be that high.
Let me know if you have any more questions -