In a decision that could impact developers across the state, the California Supreme Court ruled unanimously Monday to allow Los Angeles and other cities to require that developers provide affordable housing as a condition of getting building permits.

Monday’s decision upheld a 2010 San Jose law, requiring housing developers to set aside a certain number of units – 15 percent of any projects larger than 20 units – as affordable. The California Building Industry Association, a trade group in Sacramento, had sued San Jose over the issue.

Now that the Court has ruled in San Jose’s favor, the association is weighing its legal options, said the group’s chief executive, David Cogdill. He argued that regulations, including affordability requirements, have made it more difficult and more expensive to build in California, which is one reason the state lacks an ample housing supply.

“The homebuilding industry, and by extension new home buyers, are now being required to solve a problem not of their creation,” he said of the court’s ruling. “This fuels the tortured logic that we can make housing more affordable by making it more expensive.”

Gary Toebben, chief executive of the Los Angeles Area Chamber of Commerce, said he agreed with Justice Ming Chin, who wrote in a concurring opinion that “the community as a whole should bear the burden of furthering this interest (of making housing affordable), not merely some segment of the community.” Toebben said just because cities can mandate affordable units doesn’t mean they should, and that leaders should work with developers to figure out how best to build more affordable housing, rather than simply handing down mandates.

“The important thing I hope this decision sends to elected officials is providing more affordable housing in California should be a collaborative effort,” he said. “As communities consider their options, we hope their first step is to sit down with builders and developers to discuss options for building more affordable units.”