According to the Los Angeles County Assessor’s office, new construction to the existing home, including ADU, JADU and patios, pools etc. is assessed at market value upon completion. However, the existing land and structures not involved in new construction will not be included in the reassessment. The increment of value determined for the newly constructed property (ADU or JADU), will be added to the existing assessed improvement value.  Example:  LANDIMPROVEMENTTOTAL Existing Assessed Value:$220,000$300,000$520,000 Market value of ADU on completion: $100,000$100,000 New Assessed value:$220,000$400,000$620,000   For more information, visit the LA Assessor’s ADU FAQ page.