Massachusetts has the most demanding security deposit law in the country. M.G.L. c. 186, § 15B doesn't just cap the amount — it prescribes a procedural machine: a specific receipt when you take the deposit, a statement of condition on a deadline, a separate interest-bearing account in a Massachusetts bank, an annual interest payment, and a sworn itemized statement at move-out. Miss certain steps and you don't just owe the deposit back — you forfeit the right to keep any of it and can be liable for three times the deposit plus interest, court costs, and attorney's fees.
That's why many Massachusetts attorneys tell small landlords not to take a deposit at all. This guide is the other path: what § 15B actually requires, in order, so you can take one correctly.
The one-month cap — and everything else you can charge
At or before the start of a tenancy, M.G.L. c. 186, § 15B(1)(b) limits a landlord to exactly four charges:
- First month's rent,
- Last month's rent,
- A security deposit no greater than one month's rent (§ 15B(1)(b)(iii)), and
- The actual cost of a new lock and key.
That list is exclusive. Application fees, pet deposits, "move-in fees," and cleaning deposits are not on it, and Massachusetts courts have treated charging them at the start of a tenancy as a § 15B violation. If your lease was drafted for another state, this is usually the first clause that breaks.
Day one: the receipt and the statement of condition
Two paper obligations attach the moment money changes hands.
The deposit receipt (§ 15B(2)(b)): when you receive the deposit you must give a signed receipt showing the amount, the name of the person receiving it (and the landlord's name if an agent received it), the date, and a description of the premises.
The statement of condition (§ 15B(2)(c)): upon receiving the deposit — or within 10 days after the tenancy begins, whichever is later — you must give the tenant a written statement of the unit's present condition, listing existing damage and any code violations. The statute prescribes required language, and the tenant gets 15 days to return it with their own notes. This document is also your deduction evidence at move-out: damage you didn't record at move-in is hard to charge for later.
The separate account: where § 15B actually catches landlords
Under M.G.L. c. 186, § 15B(3)(a), the deposit must be held in a separate, interest-bearing account in a bank located in Massachusetts, protected from the landlord's creditors. Commingling the deposit with personal or business funds is the classic violation. Within 30 days you must give the tenant a receipt identifying the bank's name and location, the amount, and the account number.
This is the step that turns casual landlords into defendants: keeping the check in your operating account — even with every intention of returning it — is itself a forfeiture trigger under § 15B(6)(a), and it sits in the treble-damages tier described below.
The 5% interest clock
M.G.L. c. 186, § 15B(3)(b) entitles the tenant to interest at 5% per year, or the lesser amount actually received from the bank, accruing from the first day. You must pay it (or credit it against rent) each year on the tenancy's anniversary; if you don't within 30 days, the tenant may deduct it from their next rent payment. Interest on the balance is also due at the end of the tenancy.
The same interest mechanics apply separately to last month's rent collected up front (§ 15B(2)(a)) — a detail even careful landlords miss, and one with its own treble-damages exposure.
Move-out: 30 days and a sworn itemized list
Under M.G.L. c. 186, § 15B(4), you must return the deposit or the balance within 30 days after the tenancy ends. If you deduct for damage, the deductions must come with an itemized list sworn to under the pains and penalties of perjury, supported by written evidence — estimates, bills, invoices, or receipts. Normal wear and tear is never deductible.
Compare that to Texas's 30-day rule, where an unsworn itemized letter suffices: Massachusetts demands a notarized-grade statement with documentation attached. A handwritten "cleaning: $300" does not survive small-claims scrutiny here.
The forfeiture list — and the treble-damages tier
M.G.L. c. 186, § 15B(6) strips a landlord of the right to retain any portion of the deposit for:
- (a) failing to put the deposit in the required separate account,
- (b) failing to provide the itemized, sworn list within 30 days,
- (c) using a lease that tries to waive § 15B rights or conflicts with them,
- (d) failing to transfer the deposit properly when the property is sold, or
- (e) failing to return the deposit or balance, with interest, within 30 days.
Then § 15B(7) sharpens three of those. For violations of (6)(a), (d), or (e), the tenant is entitled to three times the deposit or balance wrongfully withheld, plus 5% interest, plus court costs and reasonable attorney's fees — and the fee award is what makes tenant-side attorneys take these cases. On a $2,400 Boston deposit, the arithmetic is $7,200 plus interest plus both sides' costs, over money that was never yours to hold loosely.
How Massachusetts compares
Massachusetts is the outlier on our security deposit rules in all 20 states we cover: most states regulate the return of the deposit; Massachusetts regulates its entire life cycle. Washington conditions deductions on a signed checklist; Massachusetts requires the checklist and the segregated bank account and the annual interest payment. If you self-manage in more than one state, don't reuse a lease across them.
Common mistakes
Holding the deposit in your own account. The § 15B(6)(a) violation with § 15B(7) treble exposure — and the single most common one.
Skipping the statement of condition. Without it you lose both a statutory duty and your best deduction evidence.
Forgetting the annual interest payment. The 5% (or bank-rate) payment is due every anniversary, not just at move-out.
Charging a pet deposit or move-in fee. The § 15B(1)(b) list of permitted upfront charges is exclusive.
Using an out-of-state template. Any clause that waives or conflicts with § 15B is itself a forfeiture trigger under § 15B(6)(c).
Build a compliant Massachusetts lease — $29 one-time, generated in minutes, with the § 15B deposit clauses, statement-of-condition workflow, and receipt language built in. See also our plain-English security deposit glossary entry.
Statutory references
- M.G.L. c. 186, § 15B(1)(b) — exclusive list of move-in charges; deposit capped at one month's rent ((1)(b)(iii)). Official text
- M.G.L. c. 186, § 15B(2)(a)–(c) — last-month's-rent interest; deposit receipt; statement of condition within 10 days.
- M.G.L. c. 186, § 15B(3)(a)–(b) — separate interest-bearing Massachusetts bank account + 30-day bank receipt; 5%-or-bank-rate annual interest.
- M.G.L. c. 186, § 15B(4) — 30-day return; sworn, itemized, documented deduction statement.
- M.G.L. c. 186, § 15B(6)–(7) — forfeiture triggers; treble damages + 5% interest + costs + attorney's fees for (6)(a), (d), (e).