So, some offenders are now claiming they are homeless to get around the law.
Keeping track of San Francisco's sex offenders is no easy job for probation officers like Arturo Herrera and Christy Henzi.
There are about 300 who've been released from county jail. Those getting out of "state" prison pose an even trickier problem, because they fall under what's known as Jessica's Law.
The law, passed by California voters in 2006, prohibits sex offenders from living within 2000 feet of schools, parks and other places close to children. That's tough in San Francisco.
"It makes it just about impossible for them to find housing therefore the State Department of Corrections has advised them to declare themselves homeless as a result they become even more desperate," said San Francisco supervisor Jake McGoldrick.
San Francisco supervisor Jake McGoldrick says 53 sex offenders were paroled in the city last month, 48 declared themselves homeless. At a state hearing on Monday, a member of the city's Police Commission called the situation bad news.
"Registering as transient is not an option; it's not a viable option. We will lose track of them," said San Francisco Police Commissioner Joe Alioto Veronese.
Not comforting to this victim.
"The idea that a bunch of people can register as transients and be anywhere is very concerning to me," said victim Temojai Inhofe.
There is also confusion about who's responsible for enforcement; the state or local governments, and where is the money to pay for monitoring.
The county Probation Department says it's already stretched to the limit.
"So ours and other Probation Departments I've talked to around the state are faced with the same challenge of not having the resources to comply with these laws," said deputy probation officer Cristel Tullock.
There is now a legal challenge by ex-offenders before the California Supreme Court.
