National City, California, was only getting a paltry 6 percent collection rate on the tardy sewer bills it had turned over to a private collection agency. Then San Diego County's Office of Revenue and Recovery made the city an offer it couldn't refuse: The county promised to collect on at least 40 percent of the overdue bills.

It's not unusual for counties to collect bills for localities. Property taxes in Illinois are collected at the county level, while smaller counties in Georgia typically collect the money for utility- type services such as garbage. But it's rare that a county would take over a city's delinquent-revenue accounts.

"We have tools that private agencies don't have," says Gary Colbert, director of Revenue and Recovery. As a county agency, the office has access to civil and criminal records and can do garnishments and writs on wages. The county will charge National City 35 percent of the money it collects, taking in an estimated $50,000 a year for itself.

Colbert's office is in the middle of a three-year debt-collection contract with the county, having survived a move toward outsourcing when private agencies decided they couldn't meet high collection targets. The office brought in $16 million last year in collected debt.

Revenue and Recovery is just an opening wedge as San Diego County explores the merging of services with several of the government entities within its border. "Our county board of supervisors wants to start partnering with cities, not just on collections but on other services," Colbert says. "This is part of the strategy."