GILROY -- South of San Jose, Santa Clara County stretches into its past, the state's third largest metropolis giving way to suburbs surrounded by vineyards, crops and pastureland.

The remaining rural stretches of this largely urban county defend their small-town roots aggressively. An initiative on next week's ballot, however, has raised concerns that the county's quietest pockets may change for the worst.

Proposition 83, the so-called Jessica's Law initiative, will prohibit paroled sex offenders from living in many urban areas, leading to a potential exodus of offenders to less populated regions.

"I wouldn't see that as a good deal for rural areas," said Jason Evans, who lives north of Gilroy and fears for his daughter, 11, and son, 9, if sex offenders begin moving to the region in significant numbers. "The services are already stretched. It's a constant, ongoing battle."

The measure would require lifetime satellite tracking of felony sex offenders, increase sentences and parole terms for violent and habitual sex offenders, and make more sexually violent predators eligible for indefinite commitments to state mental hospitals.

Of Proposition 83's many provisions, the most controversial prohibits registered sex offenders from living within 2,000 feet of a school or park.

That expands the distance requirements and the number of offenders affected by existing state law. Paroled sex offenders now are prohibited from living within a quarter-mile -- or 1,320 feet -- of a school, with a half-mile restriction for high-risk sex offenders.

Law enforcement and social service workers worry that those residency requirements will make it virtually impossible for paroled sex offenders to find places to live within urban areas. Some may simply stop reporting their addresses so they won't have to move.

The less-populated regions where they could find a home have relatively few treatment services for sex offenders and fewer police to track their movements.

In south Santa Clara County, for example, few treatment options exist for sex offenders, said Perla Flores of Gilroy, who directs sexual assault programs for the Community Solutions rape crisis center.

The organization already is overwhelmed by about 100 sexual assault victims each year and can't afford to hire additional counselors, she said.

The sheriff's department also can't afford to hire more deputies to monitor paroled sex offenders who move to outlying areas, said Santa Clara County Sheriff's Deputy Serg Palanov.

"It's definitely going to be affecting us, because the unincorporated areas we cover don't have a lot of schools and parks," he said. "We might end up picking up a lot of those people."

Moreover, the sheriff's department isn't sure how it would monitor the satellite tracking of sex offenders as required by Jessica's Law.

The measure would force an estimated 5,500 parolees to move immediately, including about 2,400 ex-convicts in Los Angeles County alone, according to a draft analysis by the California Department of Corrections and Rehabilitation's Division of Adult Parole Operations.

"Most parolees will be unable to secure housing, and many will be forced to leave their families and quit their jobs," states the report, which was obtained Tuesday. "They will no longer have the ability to be financially responsible for their families, and this burden will fall to the local communities."

Proposition 83 supporters say the concerns are overstated.

Parolees would be fitted with Global Positioning System bracelets upon release from prison, making it harder for them to disappear, said David LaBahn, executive director of the California District Attorneys Association.

After a sexual assault has occurred, police can quicken the pace of their investigation by using that system, he said.

That eases the fears of Gilroy resident Judi Brem, who worries that her 13-year-old granddaughter could be a target.

"As long as they can track them, that would help," Brem said.

The nonpartisan Legislative Analyst's Office estimates that satellite tracking will cost California law enforcement agencies about $100 million a year within 10 years.

Nick Warner, who represents associations for sheriff's deputies, probation officers and rape investigators -- all of which support the initiative -- said most sheriff's departments will be able to shift their existing patrols to cover sex offenders in rural areas.

While its language is unclear, Jessica's Law is not intended to force California's 105,000 registered sex offenders to move if they already live in a restricted area, said state Sen. George Runner, R-Lancaster, the measure's co-author.

The housing restrictions primarily would apply to new parolees as they are released back to the counties where they lived when they committed their crime.

Jessica's Law's residency provisions are only slightly more severe than existing law, prompting Runner to suggest that it will not lead to a dramatic shift in the population of offenders.

"Nobody's being forced to outlying areas of Los Angeles County (now)," he said. "San Francisco's tough, but San Francisco is tough now under current placement (restrictions) of a quarter-mile."

Jessica's Law allows counties to impose their own residency requirements if they are tighter than those mandated in the initiative.

San Bernardino County is among those doing just that for its outlying areas.

County supervisors are considering an ordinance saying registered sex offenders could not live within 2,000 feet of daycare centers and within a half-mile of schools in unincorporated areas. They also will not be allowed to loiter within 300 feet of schools or parks. Final consideration of the ordinance is set for Election Day.

State Sen. Dean Florez, D-Shafter, who represents Fresno, Kern, Kings and Tulare counties, said he will seek legislation next year setting uniform restrictions in rural areas to prevent such local ordinances from simply driving sex offenders to regions that lack their own rules.

That's a concern for Jeff Ramsour, who moved from San Jose to rural Gustine four years ago.

"You don't want them around schools, but you don't want them in rural areas either," Ramsour said. "Rural areas have children, too."

On the Net:

Jessica's Law -- http://www.jessicaslaw2006.com

Opposition -- http://www.cacj.org, http://calcasapublicpolicy.org and http://ccoso.org

Legislative Analyst's report -- http://www.lao.ca.gov/ballot/2006/83--11--2006.htm