A majority of the Madison residents in a government program that helps them afford their rents are facing an immediate jump in the portion they pay because of an unexpected change in federal funding.

The increases, which vary widely but exceed 50 percent for some tenants, are triggering worry and panic among recipients and dire predictions among others.

“I simply don’t know what to do,” said Thelma Johnson, 61, a retired housekeeper who lives on Social Security and uses a wheelchair due to a bad knee. Her portion of her $835 monthly rent will go to $288 from $185 on Aug. 1, a 56 percent jump.

The increases affect people receiving Section 8 vouchers, a federal program that helps very-low-income families, the elderly and the disabled afford housing in the private market. Recipients usually pay about 30 percent of their income toward rent, with the government picking up the rest.

The money gets funneled through the city’s housing authority, which recently learned it would receive $9.5 million in Section 8 funding for 2009 instead of the $10.1 million it had counted on. The difference — $578,000 — is what’s causing the pain.

“Some people are angry, and I don’t blame them,” said Agustin Olvera, director of housing operations for Madison’s Community Development Authority (CDA).

The CDA had two options — terminate some recipients altogether or spread the pain. It chose the latter as the more humane option, Olvera said.

Consequently, 78 percent of the 1,450 Madison tenants who receive Section 8 help will now pay more of their own rent, Olvera said. The CDA did not have a figure for the average percentage increase, but the average dollar increase is $107 per month.

Some recipients will not pay more because they already live in such inexpensive places that their rents fall below the new payment standard.

Tom Conrad, Madison’s Section 8 manager, said the housing authority developed its funding estimate for 2009 based on the same rules the federal Department of Housing and Urban Development used to determine the city’s 2008 allocation.

After Congress passed its budget in March, technical changes to the HUD rules ended up having a major financial impact for Madison, he said.

The housing authority got its funding total May 8 and was granted a federal waiver just two weeks ago to increase the portion tenants pay, Conrad said. Because the housing authority had operated the first six months of the year on the estimated dollar figure, it now must take quick action, he said. Recipients must start paying more Aug. 1.

“I’m going to have to juggle between paying my rent or paying my utilities,” said Kristin Alexander, 32, a single mother of six who rents a five-bedroom house. Because she’s unemployed, the Section 8 program has been paying all of her $1,499 rent. On Aug. 1, she will start paying $253.

The 30-day notice gives people little time to change their circumstances, said Michael Goldsby of Madison, the owner of a construction company that does projects in low-income neighborhoods. He’s trying to help people figure out their options.

“You have a lot of people out here with their backs to the fire, and who wants that with kids at risk?” he said.

At Avalon Madison Village, an apartment complex with 104 units, about one-third of the tenants receive vouchers, said Kevin O’Connor, who helps manage the complex. He predicts a wave of rent defaults that could lead to evictions.

“The worst part is that once you’re evicted, you’re no longer eligible for Section 8,” he said. “So we’ll have all these people without a decent place to live or to raise their families.”

In a letter to recipients, the CDA suggests tenants consider moving to less-expensive units to stretch their subsidies.

“That’s ridiculous,” said Barb Zimmerman, 47, who lives in a one-bedroom apartment that rents for $740 and is facing an 81 percent increase in her portion, to $319. “What if everybody on Section 8 tried to move to lower rents? There wouldn’t be anywhere left to live.”

For now, few other options appear likely. CDA staff have scheduled a conference call Tuesday with federal officials to make their case for more money, but that looks unlikely.

“I have been talking to HUD officials every day since our notification, and no one has indicated there’s a likelihood they will be able to solve this problem for us,” Conrad said.