The lessor shall, within thirty days after the termination of occupancy under a tenancy-at-will or the end of the tenancy as specified in a valid written lease agreement, return to the tenant the security deposit or any balance thereof; provided, however, that the lessor may deduct from such security deposit for the following:
(i) any unpaid rent or water charges which have not been validly withheld or deducted pursuant to any general or special law
(ii) any unpaid increase in real estate taxes which the tenant is obligated to pay pursuant to a tax escalation clause which conforms to the requirements of section fifteen C; and
(iii) a reasonable amount necessary to repair any damage caused to the dwelling unit by the tenant or any person under the tenant's control or on the premises with the tenant's consent, reasonable wear and tear excluded. In the case of such damage, the lessor shall provide to the tenant within such thirty days an itemized list of damages, sworn to by the lessor or his agent under pains and penalties of perjury, itemizing in precise detail the nature of the damage and of the repairs necessary to correct such damage, and written evidence, such as estimates, bills, invoices or receipts, indicating the actual or estimated cost thereof. No amount shall be deducted from the security deposit for any damage to the dwelling unit which was listed in the separate written statement of the present condition of the premises which was required to be given to the tenant prior to the execution of the lease or creation of the tenancy pursuant to clause (c) of subsection (2) or any damages listed in any separate list submitted by the tenant and signed by the lessor or his agent pursuant to said clause (c), unless the lessor subsequently repaired or caused to be