City Councillor Andrea Campbell last week pitched Mattapan community members on a November ballot question that would institute a city tax surcharge that would provide funds for historic preservation, parks, and housing.  Boston city councillors voted, 12-1, in May to put the Community Preservation Act (CPA) on the ballot. Mayor Martin Walsh then signed off, bringing the issue to the voters on Nov. 8. A CPA allows for a community-wide tax levy of up to three percent on property value and real estate transactions, which advocates say will provide crucial financial resources for a city badly in need of new housing. As it left the council, the act recommends a one percent property tax surcharge, with exemptions for low-income homeowners, low-income homeowners, low- and moderate-income senior homeowners, and for the first $100,000 of residential and business property values. The revenue enters a pool reserved for developing housing, broadening and improving green space, and historic preservation. Walsh said in May that Boston would likely raise $16.5 million from CPA revenue, bolstered by and another $5 million in state matching funds. Across the Commonwealth, 161 cities and towns have adopted the CPA, which the Community Preservation Coalition notes is 46 percent of all Massachusetts cities and towns. No community has repealed the act. In 2001, Boston rejected a two percent CPA measure, which supporters like City Councillor Michael Flaherty say caused the city to miss out on close to $300 million in applicable funds. The one percent rate on the ballot is as low as the city could feasibly go, said Campbell, who co-sponsored the measure for the council with Flaherty. “I support the CPA because this is the only source in the commonwealth that can generate new revenue to build housing,” Campbell said at the meeting in Mattapan last week. Some attendees inside the Mildred Avenue Community Center were stumped by the calculations. A one percent tax sounded simple, but what did it mean? One percent of the property value? Was it annual or one-time? The answers are a bit more complicated, but homeowners would be paying considerably less than a straight tax, especially after accounting for the built-in exemptions. “The typical Boston homeowner whose home is assessed at $500,000 would pay approximately $24 per year toward this investment, and in turn, the city would generate $20 million or more every year for CPA projects,” according to the Yes for a Better Boston campaign, which is advocating for the measure.  Campbell urged residents to look up their properties on the city’s CPA calculator (cpainfo.boston.gov), which estimates the annual surcharge. On average, she said, homeowners in Mattapan’s 02126 zip code would pay nothing. Nearby zip codes 02124 and 02125 would average $4-$5 as an annual surcharge. Even a small added tax burden can seem untenable, attendees noted. Some pointed to a pledged overhaul of the Mattapan Square Station that fell far short of expectations and a general perceived lack of investment in Mattapan. They asked why they should be contributing still more financially with no guarantee of a substantial payoff in a historically underserved area.  Boston already brings in more than two-thirds of its revenue from property taxes. The Fiscal Year 2015 budget projected net property tax would account for 68 percent of revenue, a slow but steady increase of nine percent since 2008.  City Councillor Bill Linehan cast the one dissenting vote on the CPA in May, saying, “As I’ve articulated throughout this exercise, I believe that we as a city rely too much on property tax for our revenue, and I believe we should be able to collectively take on the responsibility for finding new ways to find revenue for our city.” CPA funds are entirely separate from existing taxes, Campbell said. Adoption would mean local control over the money, with an independent council in charge of assessing and approving proposals.  At least 10 percent of CPA funds are required for each of the three categories ­– housing, preservation, parks – with broad discretion over the distribution of the remaining 70 percent. Boston could, like Cambridge, dedicate up to 80 percent of its allocation to housing. When voters head to the polls in November to elect officials and weigh measures addressing marijuana and charter schools, Campbell said, they also have an opportunity to give the city another resource in its pursuit of a sustainable housing stock. “If it doesn’t get voted in, it doesn’t change anything” she said. “Everything would remain the same: No taxes, no money from the state for CPA funds, and we continue to go as we are. We will continue to have a housing crisis. It will only get worse.”