"It's not a theoretical exercise. There are people who will be homeless because of this," said Paul Chrystie, spokesman for the city Office of Housing and Community Development.
The Philadelphia Housing Authority, which gets almost all its money from D.C., announced last month it will lay off 80 workers - Philly's first tangible result of the policy.
The city is still waiting for the price tags on other cuts, said Terry Gillen, Mayor Nutter's federal liaison. The administration has, however, made some projections: There could be 400 fewer slots for Head Start early education, 100 fewer homes could have lead removed and 80 homeowners facing foreclosure may lose financial counseling services.
"It's devastating because a lot of them would hit poor people," Gillen said.
The beleaguered school district will be affected as well, losing millions in grants like Title I funding for disadvantaged schools.
And federal workers in Philly may see furloughs or benefit cuts.
Overall, sequestration will cut $85 billion this year and, if left unchanged, $1.2 trillion in all by 2021, with defense and domestic spending shrinking evenly. While some think that degree of belt-tightening is needed, few are happy with how it plays out under the policy.
"People have every right in the world to be pissed off at us. It's a total disgrace," said U.S. Rep. Bob Brady, D-Philadelphia. "The sequestration's crazy."
So how did it happen?
In 2011, House Republicans vowed not to raise the federal debt limit without equal spending cuts. President Obama and GOP leaders struggled to compromise on a way forward, and the result was the Budget Control Act, which abdicated the task of finding $1.5 trillion in cuts over 10 years to a "super committee."
If the committee failed, the sequester would follow. It was designed to be so undesirable that the committee would be compelled to find a solution.
That didn't happen.
All Pennsylvania members of the House except Pittsburgh Democrat Mike Doyle voted for the Budget Control Act. So did Democratic Sen. Bob Casey. Republican Sen. Pat Toomey voted against it but served on the failed "super committee."
"Clearly, the cuts could be done more wisely," Toomey said in a statement. "There are innumerable opportunities for savings in the federal budget, including unneeded projects, duplicative missions, waste and fraud."
Toomey has put forward a plan that would retarget the cuts and protect certain military spending. Obama, in the budget proposal he laid out this week, also introduced a way to avert across-the-board cuts. But even if a substitute passes, it isn't likely to stop the $85 billion in cuts this year.
Dr. Donald Schwarz, deputy mayor for health and opportunity, said that after years of cuts during the recession, there's not much fat to be trimmed.
"Anything that's cut at this point cuts something real," he said.
On Twitter: @SeanWalshDN