In 1978, California voters passed Proposition 8, a constitutional amendment that allows a temporary reduction in assessed value when a property suffers a €œdecline-in-value.€ A decline-in-value occurs when the current market value of your property is less than the current assessed value as of January 1.
For full details please follow the link to the Los Angeles County Office of the Assessor : http://assessor.lacounty.gov/extranet/guides/prop8.aspx