Starting January 1, 2017, water conservation retrofitting goes statewide for single family dwellings. All homes built on or before January 1, 1994 are required to update to complying water conserving fixtures on or before January 1, 2017. Commercial buildings and multi-family units built prior to January 1, 1994 are required to make the transition on or before January 1st 2019.
A seller or transferor of single-family residential real property, multifamily residential real property, or commercial real property must disclose to a purchaser or transferee, in writing, specified requirements for replacing plumbing fixtures, and whether the real property includes noncompliant plumbing. Fixtures include water closets, urinals, showerheads, lavatory faucets, and kitchen faucets. Noncompliant fixtures can only be replaced by fixtures complying with the requirements of CALGreen and the California Plumbing Code.
As of January 1, 2014, SB 407 requires non-compliant plumbing fixtures to be replaced by water-conserving plumbing fixtures when a property is undergoing alterations or improvements as defined by the California Building Code and California Green Building Code. These codes define alterations and improvements as any construction to an existing structure which enhances or improves the structure. Construction related to repairs or maintenance of the structure are not considered to be an alteration or improvement.
For more information, please check out these useful links:
http://www.bsc.ca.gov/Codes.html