The developer of a 36-unit apartment building at 233 Hancock St. has notified the BPDA it is planning to increase the number of affordable units from 5 to 10 and to restrict the rent on another 11 units - in part due to funding from a property-tax surcharge approved by Boston voters in 2016.

The BPDA approved the project last fall with the minimum 5 units required under the city's affordable-housing regulations.

In a filing with the BPDA, Benjamin Moll of ARX Urban Capital says he was able to increase the number of income-capped units through two new sources of funding: $500,000 from the city fund set up under the Community Preservation Act approved by voters and a subsidy from a state workforce housing fund.

The 10 "affordable" units will be available to people making no more than 70% of the Boston area median income; the other units to people making up to 100% of that income.

Technically, the BPDA has to approve the increase in affordable units because it approved the project under regulations that required just the 5 affordable units.