Williamson Act

History and Background

The California Land Conservation Act of 1965, also known as the Williamson Act, was adopted by the State Legislature in 1965 and voluntarily implemented by the Stanislaus County Board of Supervisors in January of 1969. The Act permits a landowner, whose land is used for agriculture, to enter into a contract with the County guaranteeing that the land will continue to remain in farming for a period of at least ten years. In return for this guarantee, the County assesses taxes based on the agricultural value of the land rather than the market value.

Uniform Rules

As allowed by Government Code, Stanislaus County has adopted Uniform Rules to clearly identify the contract terms for every landowner of agricultural land within the agricultural preserve. These rules are locally adopted and subject to compliance with all applicable State regulations. Provisions of the Williamson Act which are not specifically identified in these rules are still applicable to all contracts located within the Stanislaus County Agricultural Preserve. Since the Williamson Act's initial adoption and implementation, numerous amendments to the Williamson Act have been made by the State Legislature. All existing and future contracts are subject to compliance with all legislative amendments made during any part of the life of the contract.

Stanislaus County Agricultural Preserve

Only parcels that are located within a designated agricultural preserve may be enrolled under a Williamson Act. The Stanislaus County Agricultural Preserve was amended on October 20, 1970 to include all lands within the A-2 (General Agricultural) zoning district.

Life of a Contract

When a contract is signed, it is good for a period of ten years. After the first year of that ten year period, one more year is automatically added to the term of the contract so that it is always valid for ten years. If a person does nothing to stop this automatic addition of a year, the contract will go on indefinitely. The contract does not run for a period of 10 years and then stop. See the Contract Non-Renewal section of these rules for information on stopping the automatic renewal of a contract.


Stanislaus County has implemented Assembly Bill (AB) 1265 providing an opportunity for counties to offset a portion of the loss of Williamson Act Subvention funds by establishing a local self-help subvention program. AB 1265 allows counties to voluntarily implement new contracts that are ten percent shorter in return for a ten percent reduction in the landowner's property tax relief. The increased revenue resulting from the reduction in the landowner's property tax relief is transferred directly to the County's General Fund. If a landowner does not want to participate in a nine year contract with its reduced level of benefit, the landowner has the option to non-renew the contract. Counties are eligible to participate if they determine that the County received less than one-half of the foregone property tax revenue (Williamson Act Subvention funds) pursuant to Government Code Section 16142(e) for the previous fiscal year. AB 1265 is a temporary solution remaining in effect only until January 1, 2016. Senate Bill 1353 enacted in 2014 authorizes the local self-help subvention program indefinitely when locally implemented.

Documents of Interest