Legal Question in Landlord & Tenant Law in Massachusetts

The short answer is no. The longer answer is no and you may open yourself up for treble damages from your tenant in the amount deducted. There are a few questions that come to mind, namely how are repairs covered in the lease agreement, was the tenants repairs done in a reasonable and cost efficient manner, and how long was the tenant without a kitchen sink before repairs were done.

I refer you to Mass. Gen. Laws Ch. 186 Sec. 15B (2)(d)(iii)(4) which enumerates the ways in which a landlord may deduct money from a security deposit. It is worth noting that from the facts set out in your question, your situation does not conform to any of legal deduction methods.

http://www.mass.gov/legis/laws/mgl/186-15b.htm

Your appropriate course of action is to seek retribution of your money through an action for rent.