Riverside County participates in the State of California Land Conservation Act or also known as the Williamson Act, agricultural land preservation program. The purpose of the Act is to preserve agricultural and open space lands by discouraging premature and unnecessary conversion to urban uses. Williamson Act contracts are established between the landowner and the County.
The Riverside County specifies local rules for processing agricultural preserve applications in Resolution No. 2026-016 and specifies compatible uses within agricultural preserves in Ordinance No. 509.
Agricultural Preserves
An Agricultural Preserve is an area defined by the County in which they are willing to accept Williamson Act contracts. Land defined as an Agricultural Preserve do not have to be placed under a Williamson Act contract. An Landowner can enlarge, establish, diminish, or disestablish their Agricultural Preserve parcel(s). Although, each type requires different process and time frames for completion.
Williamson Act - Contracts
Landowners receive substantially reduced property tax assessments in return for enrollment under Williamson Act contract. Property tax assessments of Williamson Act contracted land are based upon generated income as opposed to potential market value of the property. The County of Riverside Assessor-County Clerk-Recorder provides information on assessment and valuation.
*If an Landowner's land is identified as an Agricultural Preserve and is under a Williamson Act contract, the contract must be first nullified prior to enlargement, establishment, diminishment, or disestablishment.
Non-renewal
Contracts may be exited at the option of the landowner by initiating the process of term Non-renewal. Under this process, the remaining contract term (nine years in the case of an original term of ten years) is allowed to lapse, with the contract null and void at the end of the term. During the Non-renewal process, the annual tax assessment continually increases each year until it is equivalent to current tax rates at the end of the nonrenewal period.
Cancellation
A contract may be cancelled without completing the process of term Non-renewal. Contract cancellation, however, involves a comprehensive review and approval process, and the payment of a fee by the landowner equal to 12.5 percent of the full market value and tax assessment of the property in question.
The below forms are required from the applicant and are reviewed to ensure the application package is complete. Please note that the Supplemental Information Form contains information and requires responses, as well as additional materials and documents depending on which of the types of Agricultural Preserve applications.
Required Application Forms
Additionally, below is a filing instruction checklist for Agricultural Preserve applications to ensure the submittal package is complete and contains all of the necessary components for processing:
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Application Submittal
To submit a Planning application online to the Riverside County Planning Department, please use our PLUS Online System. The following link will direct you to the PLUS Online website portal submittal instructions.
Comprehensive Agricultural Preserves Technical Advisory Committee (CAPTAC) was formed according to Government Code Section 51239 to advise the Board of Supervisors on the administration of the agricultural preserves in the county, recently amended per County Resolution No. 2026-016, dated February 3, 2026.
The composition of the committee (Division VI of the Resolution) is composed of the members of the Planning Commission. Agricultural Preserve cases will be heard at Planning Commission at a separate hearing from the entitlement project.
Documents
Maps
Agricultural Preserve Map Exhibits
*Select Bookmarks to scroll by the name of the preserve. The document is in chronological order.
*To see if the property is under contract, search with the Assessors Parcel Number (APN), Property Identification Number (PIN), or property address. Select, "View Property," If the, "Property Type," in , "General Information," states, "AP," the parcel is currently under contract.
*Select the layer, "Agricultural Preserves," under, "Planning Layers."
California Williamson Act Enrollment Finder
Resource Links
Department of Conservation: Williamson Act Program
Is an Agricultural Preserve and Contract the Same?
No, an Agricultural Preserve is an area devoted to either agricultural, recreational, or open-space use. Agricultural Preserves are not always under contract.
A Land Conservation Contract may offer property tax relief to landowners in exchange for a contractual commitment to keep their property in agricultural or compatible open space uses for a renewable period of at least 10 years. The land has to be an existing, enlarged, or established as an Agricultural Preserve to enter into a Land Conservation Contract.
What is the Land Conservation/ Williamson Act?
The Land Conservation Act of 1965 is intended to curb the premature and unnecessary conversion of farmland and to ensure a stable agricultural economy. Counties may “opt-in” to offer property tax relief to landowners in exchange for a contractual commitment to keep their property in agricultural or compatible open space uses for a renewable period of at least 10 years.
Click the link below for more information:
What is an Agricultural Preserve?
Who oversees the Land Conservation/ Williamson Act?
The County of Riverside participates in the Williamson Act, manages the enlargement, establishment, diminishment, and disestablishment of Agriculture Preserves, and creates the administrative process not explicitly mentioned in the Government Code through the adoption of Resolution No. 84-526, Ordinance 509, and internal policies and procedures.
The Department of Conservation assists local agencies regarding the policies, procedures, purposes, administration, and implementation of the California Government Code.
Click the links below for more information:
How do I know my land is in a classified as an Agricultural Preserve?
To find out if your parcel is in a Agricultural Preserve, use the MapMyCounty tool here: https://gis1.countyofriverside.us/Html5Viewer/index.html?viewer=MMC_Public
Type in your Assessor’s Parcel Number and click, “Search.” Once the search is complete, click, “Full Report.” The “Full Report” is created as a PDF in a separate tab. In the blue highlight section, “Planning,” under, “Agricultural Preserve,” will specify if the parcel is classified as one or not. If there is a Name, Number, and Map Number, that is the preserve the parcel is identified as. If it states, “Not in an Agricultural Preserve,” then it is not classified as a preserve.
How do I know my land is in a Contract?
To find out if your parcel is in a Agricultural Preserve, use the MapMyCounty tool here: https://gis1.countyofriverside.us/Html5Viewer/index.html?viewer=MMC_Public
Type in your Assessor’s Parcel Number and click, “Search.” Once the search is complete, click, “Full Report.” The “Full Report” is created as a PDF in a separate tab. In the blue highlight section, “Assessor Data,” in, “Class Code,” states, "AP," the parcel is currently under contract. If the abbreviation of, “AP” is not there, then it is not in a contracted status.
How can my land be classified as an Agricultural Preserve?
The Land Conservation Act of 1965 (Williamson Act), County of Riverside Resolution No. 84-526, and Ordinance No. 509, specifies the requirements to Enlarge or Establish an Agricultural Preserve. The property owner’s parcel must go through the Enlargement or Establishment application process with the Planning Department.
For a parcel to be eligible to be designated within an Agricultural Preserve, the parcel(s) must:
- Be in an agricultural zone in accordance with Ordinance 348:
A-1, A-P, A-2, A-D, C/V, WC-W, WC-WE, WC-E - Existing use is a Compatible Use pursuant to Ordinance No. 509
If the parcel is not currently in an agricultural zoning, a Change of Zone (COZ) Application can be concurrently filed with the Enlargement or Establishment application.
Click the link below for more information:
What is the minimum acres size for Agricultural Preserve?
An Agricultural Preserves may establish if it contains at least 100 acres of contiguous parcels or lands regardless of ownership. Two or more parcels may be combined to meet this requirement.
Enlargements of existing agricultural preserves shall generally consist of no less than 10 acres contiguous to the existing Agricultural Preserve.
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What is a Land Conservation Contract and how do I enter into one?
A Land Conservation Contract under the Williamson Act or Williamson Act Contract for short may provide property tax relief to property owners in exchange for the owner to keep their property in agricultural or compatible open space uses per Riverside Ordinance No. 509.
The amount of tax relief is not determinable, as it depends on the specific characteristics and assessed value of each property. The contract runs with the land for 10-years and renews for one extra year automatically one year after the contract is established.
A Landowner can file an Entry into a Contract form with the Planning Department if their parcel:
- Is within an Agricultural Preserve.
- Is zoned agricultural in accordance with Ordinance 348:
A-1, A-P, A-2, A-D, C/V, WC-W, WC-WE, WC-E. - Has uses on site that are listed as compatible uses within Ordinance No. 509.
Parcel(s) that are both not in an Agricultural Preserve and under contract can concurrently file a Entry into a Contract form while going through the Establishment/ Enlargement process.
Filing a Entry into Contract does not mean the contract is in effect. The Land Conservation Contract will be have to be adopted or denied by Board of Supervisors before it will come into effect.
Click the links below for more information:
How do I remove my parcel from an Agricultural Preserve?
A Landowner parcel not under the Land Conservation Contract, can be removed from the preserve through the Diminishment or Disestablishment application process. If the parcel is under contract, it would have to go through the Diminishment/ Disestablishment and Cancellation process, and or a non-renewal process.
The Diminishment or Disestablishment application process requires:
Alternative land use (implementing project).
Implementing project application.
The implementing project goes through the normative planning process concurrently with the Agricultural Preserve case.
Click the link below for more information:
How do I non-renew my Contract?
The Landowner can file a Notice of Non-Renewal, which is a notice to stop renewing their 10-year contract until it reverts back to the normal tax rate at the end of the contract period. The 10-year rolling contract no longer renews and assumes the gradual expiration process. The year following recording of the Notice of Non-Renewal may result in a significant increase in assessed value . Then, the property taxes moderately increases annually until it reaches the Factor Based Year Value at the end of the 10-year period.
To begin non-renewal, the Landowner must file a Notice of Non-Renewal by October 3rd of every year (at least 90 days prior to the renewal date of the contract). If the notice is served after October 3rd, the non-renewal period would begin in the year after.
If the Landowner is requesting non-renewal of a portion of their land under the contract, Board of Supervisors approval is required. A non-renewal of all the property does not require Board approval.
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How do I cancel my Contract?
A landowner can file a Petition of Cancellation application of the Land Conservation Contract if they do not want to wait the 10-year non-renewal process. Contract Cancellation involves a comprehensive review and approval process, and the payment of a fee by the landowner equal to 12.5% of the full market value as deferred taxes of the property in question. The Cancellation process also requires filing a Notice of Non-Renewal. This means the parcel will still go through the non-renewal process.
The Diminishment or Disestablishment with Cancellation application process requires:
- Alternative land use (implementing project).
- Implementing project application.
- Notice of Non-Renewal.
- Petition of Cancellation.
- Survey of area being diminished for partial cancellation (Partial Cancellation).
The cancellation fee is calculated by the Riverside County Assessor’s office. The calculation example provided below is an example and NOT the exact cancellation fee, but can be used to estimate your individual cancellation penalty amount.
Cancellation Fee Calculation Example: Intended / Proposed Use subsequent to Cancellation: Develop 100 medium density single family residences – Paper Lot Value times 100 lots = Cancellation Value [simplified example as other factors may impact the calculation].
The implementing project goes through the normative planning process concurrently with the Agricultural Preserve case.
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Are there any restrictions on property within an Agricultural Preserve?
The land within the preserve is automatically restricted to agricultural and compatible uses found compatible with Agricultural Preserves as specified in Riverside County Ordinance No. 509: https://rivcocob.org/sites/g/files/aldnop311/files/migrated/ords-500-509.2.pdf
How do property tax assessments change when in a Contract?
Landowners may receive reduced property tax assessments in return for enrollment under a Williamson Act contract. Property tax assessments are based upon generated income as opposed to potential market value of the property. Percentage is unique per parcel and is calculated by the Riverside County Assessor.
The assessed value will be the lower of the Factored Base Year Value and Restricted Value calculated via the law.
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Is Cannabis Allowed in Agricultural Preserves?
According to the County of Riverside Compatible Use Ordinance No. 348, Indoor and Mixed Light Cannabis Cultivation are not allowed in an established preserve or under a Land Conservation Contract: https://planning.rctlma.org/sites/g/files/aldnop416/files/2023-06/Ord348-04-28-2023-FINAL.pdf
Can I have a Rancho and be in a Agricultural Preserve?
No, in accordance with allowable uses and Rancho Community Event Facilities Ordinance 348: https://planning.rctlma.org/sites/g/files/aldnop416/files/2024-08/Rancho%20Community%20Event%20Facility%20Ordinance.pdf
Can I be a Short-Term Rental and be in a Agricultural Preserve?
No, in accordance with allowable uses in Ordinance No. 509: https://rivcocob.org/sites/g/files/aldnop311/files/migrated/ords-500-509.2.pdf
How long does it take?
Any process under the Agricultural Preserve Program can take a minimum of a year. Each process requires several hearings, approvals, etc., but the actual time taken for each project will depend on proposal complexity.
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