The law in plain English
Return deadline
Under Mass. Gen. Laws ch. 186, Section 15B, the deposit response usually has to be sent within 30 days of the move-out timeline described by the state rule.
Required notice
Massachusetts generally gives the landlord 30 days to return the deposit or send a compliant itemized statement, and statutory violations can trigger mandatory treble damages.
This dispute type
In Massachusetts, renters usually challenge deposit deductions for scuffs, faded paint, flattened carpet, and similar aging because those issues look more like ordinary use than repairable damage. The statute still controls when the refund had to be sent and how deductions had to be explained.
Penalty leverage
If the withholding was wrongful or in bad faith, the exposure allowed under the statute is: 3x the deposit, plus interest, court costs, and reasonable attorney's fees