Diana Kim RealtyDiana KimREALTOR® · eXp Realty · Boston
RentingSeptember 1, 2026

Your Massachusetts Security Deposit Has a 30 Day Clock, and It Started When the Tenancy Ended

Massachusetts security deposit law gives a landlord thirty days after the tenancy ends: a Boston landmark in early September
Photo: Nina La, CC BY 3.0

Boston turns over a lot of leases at the start of September, which means a lot of deposits are sitting with former landlords right now. Massachusetts puts a hard deadline on that money, and the deadline started the day the tenancy ended.

Thirty days, and only four deductions

Under M.G.L. c.186 §15B(4), the lessor has thirty days after the termination of occupancy under a tenancy-at-will, or after the end of the tenancy as specified in a valid written lease agreement, to return the security deposit or any balance of it. The statute names what can come out of it and nothing else qualifies:

  • Unpaid rent or water charges that have not been validly withheld or deducted pursuant to any general or special law.
  • An increase in real estate taxes the tenant is obligated to pay under a tax escalation clause that conforms to the requirements of c.186 §15C.
  • A reasonable amount necessary to repair damage caused to the unit by the tenant, reasonable wear and tear excluded.

The sworn list

A landlord can’t just put a number in a letter and keep it. §15B(4)(iii) requires an itemized list of damages, sworn to by the lessor or the lessor’s agent under pains and penalties of perjury, together with written evidence such as estimates, bills, invoices or receipts. That list is due to the tenant within the same thirty days after termination of the occupancy.

Interest at five percent, with two conditions

A security deposit the lessor has held for a period of one year or longer from the commencement of the term earns interest under §15B(3)(b) at the rate of 5% per year, or other such lesser amount of interest as has been received from the bank where the deposit has been held, payable to the tenant at the end of each year of the tenancy, with all accrued interest due within thirty days if the tenancy ends before the anniversary date. Rent paid in advance for the last month of the tenancy earns interest at the same rate under §15B(2)(a) with no one-year threshold, beginning with the first day of the tenancy, though interest doesn’t accrue for the last month for which rent was paid in advance. If you paid first, last and a deposit, two of those three amounts earn interest.

What happens when a landlord misses it

§15B(6) sets out what a landlord loses by getting this wrong. A lessor forfeits the right to retain any portion of the deposit by failing to deposit the funds in an account as required by §15B(3), by failing to furnish the itemized list within thirty days after termination of the occupancy, by using in a signed lease a provision that conflicts with the section and then attempting to enforce it or to obtain a waiver, by failing to transfer the deposit to a successor in interest, or by failing to return the deposit or balance within thirty days after termination of the tenancy. §15B(7) reaches only three of those five. If the lessor fails to comply with clauses (a), (d) or (e) of §15B(6), meaning the account, the transfer to a successor, or the thirty day return, the tenant shall be awarded three times the deposit or balance to which the tenant is entitled, plus interest at 5% from the date when payment became due, together with court costs and reasonable attorney’s fees. A late itemized list under clause (b) or a conflicting lease clause under clause (c) forfeits the deposit but does not trigger the treble award. If you’re renting in Greater Boston and thinking about buying in a year or two, that money is worth chasing. Send me the lease and I’ll read it with you. Diana Kim, REALTOR®, eXp Realty.

Questions

Common questions

How long does a Massachusetts landlord have to return a security deposit?

M.G.L. c.186 §15B(4) requires the lessor to return the security deposit, or any balance of it, 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. An itemized list of damages supporting a deduction is due in the same thirty days.

What can a Massachusetts landlord deduct from a security deposit?

Only unpaid rent or water charges that were not validly withheld or deducted pursuant to law, an increase in real estate taxes the tenant is obligated to pay under a tax escalation clause conforming to c.186 §15C, and a reasonable amount necessary to repair damage the tenant caused beyond reasonable wear and tear. Damage deductions require an itemized list sworn under pains and penalties of perjury with written evidence.

Does a Massachusetts security deposit earn interest?

Yes, if the lessor holds it for a year or longer from the commencement of the term. Under §15B(3)(b) it earns interest at 5% per year, or such lesser amount of interest as has been received from the bank where the deposit has been held, payable to the tenant at the end of each year of the tenancy, with accrued interest due within thirty days if the tenancy ends before the anniversary date. Rent paid in advance for the last month earns interest on the same terms from the first day of the tenancy.

Written by Diana Yeji Kim — REALTOR® at eXp Realty, serving Greater Boston in English, Korean, and Japanese.

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