Hundreds of thousands of illegal immigrant workers keep the Central Valley's economy humming — at a price.

Even though they help businesses by providing cheap labor and lower the costs of goods and services, they are a burden on local governments because they pay little in taxes, economists say. Their low wages, not their work ethic, are to blame.

That means the rest of us pay higher taxes or must get by with fewer government services to keep illegal immigrants here.

"So you're like, 'I only paid $2 for strawberries' — but then you get a notice about taxes going up, and you might not think those two things are connected," said Steven Camarota, a researcher with the Washington, D.C.-based Center for Immigration Studies, which supports stricter immigration enforcement.

Just how much illegal immigrants burden taxpayers is hotly debated. Even though they have limited access to public services, their U.S.-born children can get a free education and sometimes qualify for welfare and food stamps. Meanwhile, illegal immigrants contribute little in taxes because they are either paid off the books or make bare-bones wages.

The nonpartisan Congressional Budget Office says state and local governments are hit hardest. The Washington, D.C.-based Federation for American Immigration Reform, which advocates for less immigration — both legal and illegal — estimates that the state of California and local governments will spend $21.8 billion this year for services for illegal immigrants and their children.

Illegal immigrants still help the economy because their cheap labor drives down the cost of products and services — an issue The Bee will examine tomorrow. But those savings are canceled out by the cost to government services — at least on a national level, some economists say.

In the Central Valley, both their positive and negative impacts are amplified because of our dependence on them. Businesses benefit in a big way while taxpayers cover the costs.

"Residents have to pick up the tab and employers get away with paying those workers less," said Gordon Hanson, an economics professor at the University of California at San Diego, who grew up in Fresno.

Not every illegal immigrant is a burden to the government. Take Nacho, for example. He snuck across the border 23 years ago, picked grapes in Raisin City for $4.25 an hour and worked his way up to ranch manager. Now he earns about $50,000 a year, owns a house in Kerman, is raising a family and pays his taxes. He doesn't receive government aid.

But Nacho is the exception. The median household income for illegal immigrants nationally is $36,000 — well below the $50,000 median household income for U.S.-born residents, according to the Pew Hispanic Center. Illegal immigrant farmworkers, who usually work only part of the year, earn even less. About one-fifth of adult illegal immigrants and one-third of their children live below the poverty line — almost double the poverty rate for U.S.-born residents.

Although their taxes may be small, illegal immigrants do pay them. That's because most come here to work.

The Center for Immigration Studies estimated that in 92% of illegal immigrant households in 2007, at least one person was working; the same was true for only 73% of households headed by a U.S.-born resident. The Pew Hispanic Center has made similar estimates. Illegal immigrants usually have higher employment rates because they'll work at almost any job and are more mobile than U.S.-born workers and legal immigrants, experts say.