The law, which was passed by the City Council in January, also requires film companies to pay a permit fee that would pay for inspections.
Supporters of the ordinance say it will help curb the spread of HIV. Opponents say the measure threatens an industry that produces millions in revenue.
Despite several HIV scares last year that halted production, adult film industry producers said they don't need condoms to protect actors from sexually transmitted diseases and that they already employ monthly testing safeguards.
Porn studios have threatened to move filming out of city limits, but supporters said moving isn't an easy solution.
"The industry does not like this law. They say that they will go to other cities or other jurisdictions, but they'll be covered by the state law there, plus we have vowed we will follow them wherever they go," said Ged Kenslea of the AIDS Healthcare Foundation.
The Free Speech Coalition, which opposes the new law, said it's a government intrusion.
"It is the government intruding into how we make films," the coalition said in a statement. "It is the government intruding into sexual behavior between consenting adults. This ordinance is a very bad idea and is now a very bad law."
Activists are continuing to gather signatures for a ballot that would extend the law countywide, affecting dozens of communities. The Simi Valley City Council has passed a similar law. Other cities, such as Moorpark, are considering their own ordinances.