AMID the flurry of school notices coming home in my kids’ backpacks, the PTA donation envelope carries a nostalgic pang. I remember thinking, only four years ago as my first child entered school, that a modest contribution to the PTA was my only cash obligation to New York City’s public schools — beyond being a dutiful taxpayer, of course.

Back then, I could still be shocked by the insanity of the school supply lists, 20 items long. (Did anyone find the “construction paper 10 by 14 ONLY” or the packages of “ALL-BLACK” dry erase markers, and couldn’t the city purchase all this stuff far more cheaply in bulk and charge us less than we now pay?) I was blissfully unaware then that I would be adding to my working-parent duties the task of fund-raising for our school.

I’m not talking about making cupcakes for the bake sale to pay for field trips. At the school my children attend in Upper Manhattan, the PTA pays for professional development for teachers, to help them meet the demands of the new common-core curriculum (an underfunded mandate if there ever was one). Parents have also set up a 501(c)3 nonprofit group to raise money for in-school “enhancement” programs. Without it, the elementary school would have no art (though there are just 15 weeks of instruction, once a week, for most classes). There would be no science classes for the youngest children. Nor would we have a Junior Great Books literacy program for third and fourth graders. Middle school students would miss out on any exposure to a second language, as well as the 14 days of crosscurricular writing provided by the nonprofit Teachers and Writers Collaborative. And there would be no prep course for eighth graders taking the high school admissions test.

To pay for all this, parents raised $185,000 last year.

The holes parents are being asked to fill keep getting deeper. Since the 2009-10 academic year, the school — by no means unique or the hardest hit — has seen its budget reduced by more than a million dollars. It has lost “extras” like teacher-led after-school programs (some of which are now being supported by the PTA), then support staff, then teachers, then more support staff and more teachers. In response, parents have tap-danced for donations (at our annual talent show) and pleaded with passers-by on the sidewalk for donations. As the neighborhood has become more desirable, partly because of parent involvement in the school, the number of students who are eligible for free lunches has declined to about 40 percent, resulting in a loss of about $500,000 in federal money over the last few years. Our school is now in the familiar middle-and-working-class bind, not poor enough for assistance but not rich enough to make up for the loss of those federal dollars.