Gov. Jerry Brown's plan for sweeping public pension reform would hit the pocketbooks of employees who hope to collect a pension check and paycheck at the same time.

It's a common practice statewide -- especially in law enforcement -- and the central San Joaquin Valley is no exception.

Visalia Police Chief Colleen Mestas, for example, gets an annual pension of about $55,000 based on her 20 years with the Fresno County Sheriff's Department and also collects $140,000 a year, including benefits, from her current job.

And in a well-publicized move this summer, Fresno Police Chief Jerry Dyer spent a few months working as a retiree, with an annual income (combining his pension and interim contract) estimated at about $300,000 -- well beyond the $169,700 a year he had been earning before he announced his retirement.

The practice, known as double dipping, would be banned under Brown's plan for all public employees in California.

Last month, Dyer, 52, gave up his pension perks to return to his job full-time.

The 46-year-old Mestas and other retirees who already are working a second public-sector job likely would be grandfathered in if Brown's plan goes into effect -- a Legislative Analyst's Office concludes that the government likely can't stop workers who already are double dipping.

A ban might sound fiscally responsible, but some officials argue it could keep experienced professionals from filling key jobs. Others say it doesn't really save money.

But reformers say public employee retirement systems can't afford years of pension payouts to those who stay on a government payroll, and that reforms would save money in an era of steep budget cuts.

The governor's plan was introduced in October and is supposed to get more legislative attention next year, but some groups are pushing ahead with pension reform initiatives for the November 2012 ballot.

The public favors pension reform. A Field Poll released this month shows bipartisan support for Brown's proposed reforms, with nearly two-thirds saying they support reduced retirement payments for public workers.

It's unclear how many public officials in Fresno, Tulare, Kings and Madera counties are double dippers. Experts say that no research has been done to calculate how many are working in government in California, or how much it's costing pension systems.

But at least 12 cases in the central San Joaquin Valley fit the profile -- and many hold senior positions.

Mestas said she left her job as a Fresno County sheriff's captain to advance her career; her pension gave her the financial security to gamble on taking a new job, she said. She became Visalia's assistant chief on July 7, 2008 -- only days after leaving the Sheriff's Department. She was promoted to Visalia chief in 2009.

"I can see where it'd be a perception problem with the public if you retire with 100% retirement and then went and got another salary," Mestas said.

For government managers who hire for key positions, retirees from another agency bring "experience and maturity" to their new job, said Jean Rousseau, chief administrative officer for Tulare County.

But Sen. Joe Simitian, D-Palo Alto, who has submitted bills banning double dipping by California Public Employees' Retirement System (CalPERS) retirees, said the practice is unfair to taxpayers.

CalPERS covers state employees, many cities and counties, judges, nonteacher public school employees and California State University employees, among others.

"Revolving-door double dippers, they aren't really retiring," Simitian said. "We've gotten away from the notion that a pension plan is designed to provide a secure retirement. Now it's a form of supplementary income."