No, the landlord may not do this. A lease is a contract; a landlord may charge any fee that is listed in the lease--but no fees that are not. The only exception would be if there was some term or clause in the lease which gave the landlord the right to add or impose fees later; if so, he could impose a new fee to the extent it complies with the lease. The lease is the cornerstone of the landlord-tenant relationship; it sets out the parties' resprective rights and obligations.