SECTION 1. Section 38 of chapter 59 of the General Laws is hereby amended by adding the following subsections:-

(a) In any given fiscal year, the assessed value of an existing residential property, defined as a property not classified as new construction or fully reconstructed, shall not result in an increase in property taxes of more than 20% over the taxes assessed in the previous fiscal year.

(b) Properties that have been reassessed due to a triggering event as defined under existing law, including the sale of comparable properties within a 2% sample size, shall not be subject to further reassessment or additional concurrent property tax increases for a period of at least three fiscal years following the initial reassessment.

(c) For the purposes of this section, “existing residential properties” shall include homes constructed prior to the sale or reconstruction of comparable properties within the triggering event sample size.

SECTION 2.  The Massachusetts Department of Revenue shall provide guidelines for implementation and monitor compliance by municipalities. Homeowners shall have the right to appeal any assessment that violates the provisions of this act through the established appeals process.

SECTION 3.  If any provision of this act is found to be invalid or unenforceable, the remaining provisions shall remain in full force and effect.