 Petris was also the co-author of the Lanterman-Petris-Short Act, which brought changes to the mental health system in California.He was a supporter and advocate of Save The Bay, a nonprofit organization that was successful in restricting and managing land development around the San Francisco Bay.He was a co-sponsor of the McAteer-Petris Act which established and governs operations of the San Francisco Bay Conservation and Development Commission (BCDC).