San Francisco becomes first big U.S. city to require solar panels on new buildings

The San Francisco Board of Supervisors passed legislation to require new construction that is shorter than 10 floors to install solar panels or solar water heaters on top of new residential and commercial buildings.

Currently, California law requires all new buildings with 10 floors or less to have at least 15% of their rooftops designated as solar ready, in other words, not in the shade. The new San Francisco law makes it the first major US city to mandate solar panels on new construction. A few smaller California communities have already adopted solar mandates.

The new rules go into effect January 1, 2017. One city legislator has introduced a bill that would allow people to add a living roof like a garden instead of installing PVs.