Mass. Gen. Laws ch. 58 § 8C
A city or town may establish, relative to sites or portions of sites that will be used as affordable housing, as defined in section 1 of chapter 60, or affordable housing and commercial, an agreement between the city or town and the developer of the sites or portions of sites, regarding the abatement of up to 75 per cent of the outstanding real estate tax obligations and up to 100 per cent of the outstanding interest and costs on the sites or portions of sites. The agreement, for the purpose of developing affordable housing on such sites and redevelopment in such communities, shall include, but shall not be limited to, the amount outstanding, the per cent of interest to accrue if determined applicable by the parties, the description of quantifiable monthly payments, the inception date of such payments, the date of the final payment, late penalties, the number of affordable units, and any other contractual obligations arranged between the parties. The terms of repayment shall be set at the discretion of the municipality and shall be included in the agreement between the parties. A city or town that accepts this section shall adopt an ordinance or by-law specifying the method for negotiating and approving agreements under this section. Copies of each such agreement shall be signed by the municipal officer required by the ordinance or by-law and by the owner of the property in question, notarized, attested to by the city or town clerk, and provided to the executive office of housing and livable communities, the city council or board of selectmen, and the owners of the property in question. An abatement under this paragraph may be granted only for a new owner of a parcel who is not liable for any of the outstanding charges secured by the municipality's lien. This section shall take effect in any city or town only upon its acceptance by such city or town. The commissioner, in consultation with the executive office of housing and livable communities, may make, and from time to time revise, such reasonable rules and regulations that are consistent with provisions of the preceding paragraph as he deems necessary to carry out the provisions of this paragraph.
Mass. Gen. Laws ch. 58, § 8C