Williamson Act & Agricultural Preserve Contracts

The California Land Conservation Act of 1965 is commonly referred to as the Williamson Act. The Act enables Napa County to enter into contracts with private landowners for the purpose of restricting specific parcels to agricultural use. The primary intent of the program is to preserve agricultural land by discouraging premature and unnecessary conversion to urban uses. Additional information regarding the Williamson Act can be obtained from the California Department of Conservation, Division of Land Resource Protection.

In return for voluntarily restricting (contracting) their land, landowners receive property tax assessments which are the lower of their factored Proposition 13 base year value or the restricted value based upon farming and open space uses (as opposed to full market value). For information regarding potential tax benefits of contracting a parcel under the Williamson Act please contact the County Assessor.


To qualify for a Williamson Act Contract a parcel must be zoned Agriculture Preserve (AP) or Agricultural Watershed (AW), be 40 acres in size for non-prime agricultural land or 10 acres in size for prime agricultural land, and contain a bona fide agricultural use (see Williamson Act Rules: Type A (PDF), Type C (PDF) and Type H (PDF)). Additionally, the County offers a contract for parcels between 5 and 10 acres provided the agricultural use demonstrates a unique commitment to sustainable farming practices and contributes to the diversity of crops raised in Napa County (i.e. agriculture use other than wine grapes) in addition to other specific conditions. Agricultural contracts are a 10 year rolling term - and renew each year for another term unless they are non-renewed by either the landowner or the County.


Applications to enroll a parcel into the program are accepted annually in the month of September. For information regarding existing Agricultural Contracts and/or processing Lot Line Adjustments that include parcels containing Agricultural Contracts, please contact us.