Can a tenant unilaterally decide to use the basement as a bedroom

[Marlin Q. Parker, Sr., Esq.]

Hello all,

I have a rental property in PA. The tenant recently informed my PM that during periods of substantial rain, some water leaks in her bedroom; furthermore, she currently uses the basement as a bedroom instead of the 3 bedrooms on the 2nd floor. The basement is a common area (boiler and hot water heater) with no privacy and no bathroom facilities; however, it does have a window and two doors (one to the the backyard and the other to the the first floor) . In addition, the basement needs to be painted and renovated. I cannot find anything in PA Code that addresses this matter for private rentals. Can we stop the tenant from doing such? In addition, we believe unauthorized tenants have actually moved into the basement and  plan to inspect the property soon. Thanks in advance for your assistance.