​​​​​​​​​​​​​​​​​​​​​​​​​​Williamson Act/Land Conservation Act

The California Land Conservation Act of 1965--commonly referred to as the Williamson Act--enables local governments to enter into contracts with private landowners for the purpose of restricting specific parcels of land to agricultural or related open space use.  In return, landowners receive property tax assessments which are much lower than normal because they are based upon farming and open space uses as opposed to full market value. 

State funding was provided in 1971 by the Open Space Subvention Act, which created a formula for allocating annual payments to local governments based on acreage enrolled in the Williamson Act Program.  Subvention payments were made through FY 2009, but have been suspended in more recent years due to revenue shortfalls.

​Open Space Subvention Act Survey​ - Now Available

The 2018 Survey of Participation in the Land Conservation Act and Open Space Subvention Act (OSSA) is now available.​​​  Please go to the Open Space Subvention Payments​ page to obtain the survey forms and for further information on the reporting requirements.

Policy and ​Legislation

Equine Facilities Policy (PDF)

AB 1265 - Advisory Statement (PDF) 
Recapture of Property Tax Loss  

​​Data and Maps

 Williamson Act Status Reports


The 2016​ Status Report is the most recent available.  Check out this page for reports dating back to 1989.


Land Conservation Act Maps (PDF)


Maps on program enrollment status, as provided by participating counties.  The most recent data submitted has been posted.   ​ ​

Working with the LESA Model

The Land Evaluation and Site Assessment (LESA) Model evaluates agricultural characteristics of specific sites, as indicated in California Environmental Quality Act (CEQA) guidelines.