Ref: Senate Bill No. 871

Generally, new construction on an existing structure will trigger a property tax RE-ASSESSMENT under the rules of Proposition 13. 

This bill exempts construction for installation of solar energy systems. Quoting from the Legislative Counsel’s Digest, “Pursuant to an authorization in the California Constitution, existing law excludes, through the 2015-16 fiscal year, from classification as “newly constructed” the construction or addition of an active solar energy system, as defined.  This exclusion will be repealed on January 1, 2017.”

Read the full bill at http://leginfo.legislature.ca.gov.