"You try to plan your cash flow perfectly, but unexpected problems and unforeseen timing can result in overdrafts for even the most careful people," Hauer said.
Pew found that overdraft fees mainly affect those making less than the national median income of about $54,000 — unsurprising, according to Susan Weinstock, director of the consumer banking project at Pew. "These people are likely to be living paycheck to paycheck to paycheck," she said.
Nearly 1 in 4 of the heavy overdrafters lost the equivalent of a week's worth of wages to fees, according to the report. Many of those choose to leave the banking system entirely as a result and now rely on even more pricey alternatives such as check-cashing storefronts, Pew found.