The Kevin Honan Apartments represent something precious - and threatened - in Boston's Allston neighborhood: affordable housing for families.

And the 39 units along Hano Street represent one of the biggest recent additions to the 500 affordable homes constructed and developed by the non-profit Allston Brighton Community Development Corporation.

Lifelong Allston resident Karen Smith loves supporting neighborhood-strengthening work like this - and she also just got a great tax break for doing it: A $1,000 donation that is going to cost her only about $400, net, out of pocket, after state and federal tax benefits.

"It was very enticing, and I have to say, I feel great about how your dollars, for an individual donor, can get stretched," Smith said in an interview Thursday afternoon. "Your money goes farther than you think. It actually costs you a lot less than you think."

The still largely-unknown new Massachusetts Community Investment Tax Credit, signed into law by Gov. Deval Patrick in 2012, just took effect last year. The way it works is, if you give the minimum $1,000 to one of the more than 40 CDCs around the state qualified by the state to get the donations, you get to take a $500 state tax credit – subtracted right off your tax liability – plus you also get to claim the $1,000 on your federal tax return as a charitable deduction, worth as much as $175 more if you're in the top 35 percent bracket.

Ultimately, a $1,000 donation can cost you just $325 out of pocket. You can get the tax break for gifts bigger than $1,000, but the maximum individual donation eligible for the 50 percent tax credit is $1 million.

"This is by far the most significant infusion of new resources into the community-development field in my memory, and probably ever," said Joe Kriesberg, president and CEO of the Massachusetts Association of CDCs, whose members got $4.8 million in donations supported by the tax break this year and will be eligible for up to $12 million this year.

Kriesberg said it's about much more than just money, because the tax credit gets individuals directly involved in evaluating the work of CDCs and deciding to support them.

"Those folks are not only bringing resources, they bring their intellectual talents, their relationships, their networks, their political connections, which can help advanced the goals of the CDCs, and another really key benefit of this program is it's forcing our members, frankly, to sharpen their message, to be clear about their impact, to measure their impact, and really tell their story in a new way to attract these resources," said Kriesberg."

"This was meant to be hard," he added, "because we want the money to go to the best organizations that are doing the best work."

Carol Ridge Martinez, executive director of the Allston Brighton CDC, said Karen Smith was among 11 donors who stepped up with $1,000 gifts. Then on top of that, New Balance Corp. offered a $10,000 match that doubled their gifts.

"For us, that was a huge infusion of funding," Martinez said. "But it also opened a lot of doors to new investors that we had never talked to before" and that are in turn making new connections for the CDC to improve its housing and neighborhood business development work.

All that – and it lets you do $1 worth of community-building good for just 40 or 35 cents or less.

"It really sounded so wonderful - is this a too good to be true story?" Smith said. "But it's true."

With videographer Chris Bonvie