In California, where foreclosures are more abundant than in any other state, homeowners trying to win a loan modification have always had a tough time.

Now they face yet another obstacle: hiring a lawyer.

Sharon Bell, a retiree who lives in Laguna Niguel, southeast of Los Angeles, needs a modification to keep her home. She says she is scared of her bank and its plentiful resources, so much so that she cannot even open its certified letters inquiring where her mortgage payments may be. Yet the half-dozen lawyers she has called have refused to represent her.

“They said they couldn’t help,” said Ms. Bell, 63. “But I’ve got to find help, because I’m dying every day.”

Lawyers throughout California say they have no choice but to reject clients like Ms. Bell because of a new state law that sharply restricts how they can be paid. Under the measure, passed overwhelmingly by the State Legislature and backed by the state bar association, lawyers who work on loan modifications cannot receive any money until the work is complete. The bar association says that under the law, clients cannot put retainers in trust accounts.