The Williamson Act is a California law, formally the California Land Conservation Act of 1965, that lets a landowner lock in a lower property tax bill by agreeing to keep the land in farming, ranching, or open-space use for at least ten years. About 10 million acres across the state are currently enrolled, making it California’s primary tool for slowing the conversion of farmland to development.1California Department of Conservation. 2022 Williamson Act Status Report In exchange for the use restriction, the county assesses your land on what it earns from agriculture rather than what a developer would pay for it. Depending on location and crop, that typically trims the property tax bill by 20 to 75 percent.
How the Contract Works
A Williamson Act contract is a voluntary agreement between you and the county or city.2California Department of Conservation. Williamson Act Program You agree to keep the property in agricultural production or compatible open-space use. The local government agrees to tax it at the lower restricted value.
The initial term is at least ten years, but the contract does not simply tick down to zero. Every anniversary, a new year is automatically added, so the remaining term stays at ten years unless somebody actively files a notice of nonrenewal.3California Legislative Information. California Code Government Code 51244 That rolling structure is the single most important thing to understand about the program. The contract is designed to continue indefinitely until someone makes a deliberate decision to end it.
The contract also attaches to the land, not the signer. If you buy property already enrolled, you inherit the agreement and every restriction that comes with it for the remainder of the term.4California Department of Conservation. Land Conservation (Williamson) Act Check the title for a recorded Williamson Act contract before closing on any rural California parcel, because getting out is slow and expensive.
Who Qualifies
The property has to sit inside an area the local government has formally designated as an agricultural preserve. State law sets a 100-acre minimum for a preserve, though counties can combine contiguous parcels to reach that figure or set up smaller preserves when local conditions justify it.5Justia. California Code Government Code 51230-51239 – Agricultural Preserves
Within a preserve, individual parcels must meet standards that differ for prime and non-prime land.
Prime Agricultural Land
Government Code Section 51201 defines prime land by several alternative tests. Land qualifies if it rates as Class I or Class II under the Natural Resource Conservation Service system or scores 80 to 100 on the Storie Index. It also qualifies if it supports at least one animal unit per acre under USDA definitions. A third path covers land planted in fruit or nut trees, vines, or similar crops producing at least $200 per acre annually in their bearing period, or land that has generated at least $200 per acre in gross value of unprocessed plant products in three of the past five years.6California Legislative Information. California Code Government Code 51201 The typical minimum parcel size for prime land is 10 acres, though the exact figure is set locally.
Non-Prime Land
Land that does not meet prime standards can still enroll if it is in active farming, ranching, or compatible open-space use. Non-prime parcels generally have to be at least 40 acres. Recreational open space and wetland habitat frequently qualify. Counties can add their own standards for what secondary activities are allowed, so specifics vary.
How Your Property Taxes Change
The tax break comes from a fundamentally different assessment method. Instead of valuing the land at what a buyer would pay to build on it, the county assessor uses a capitalization-of-income approach that values it only on its agricultural earning power.7California Legislative Information. California Code Revenue and Taxation Code 423 The assessor estimates the net income the land can reasonably produce from agriculture, then divides by a capitalization rate built from interest, risk, property tax, and (for orchards and vineyards) amortization components.
The assessor then compares three figures: the restricted income-based value, the factored Proposition 13 base-year value, and current market value. Whichever is lowest becomes the taxable value.8California State Board of Equalization. Property Tax Annotations – 620.0000 Open-Space Lands For most contracted farmland, the capitalized income figure is well below market, and that gap is where the savings come from. Counties that have adopted Section 423.3 can set a floor at 70, 80, or 90 percent of the factored base-year value, meaning the assessment will not drop below that threshold even if income math would allow it.
Farmland Security Zone Contracts
California offers a stronger version of the program called a Farmland Security Zone contract. These are available only on higher-quality agricultural land, run a minimum of 18 years instead of ten, and deliver a larger tax reduction than a standard contract.9California Department of Conservation. Williamson Act FAQ 2024 The nonrenewal countdown stretches to 19 years, and the cancellation fee doubles to 25 percent of unrestricted fair market value.
In return, FSZ land gets stronger protection from encroaching development. Cities and special districts that provide non-agricultural services generally cannot annex FSZ land, and school districts are prohibited from taking FSZ parcels for school facilities.10California Department of Conservation. Williamson Act Contracts If sprawl is pressing in on your operation, an FSZ contract offers meaningfully more insulation than the standard version.
Compatible Uses and Solar
Not every activity on contracted land has to be planting or grazing. The statute allows local governments to approve “compatible uses” as long as the activity does not significantly compromise long-term agricultural productivity, displace current farming, or push neighboring contracted land out of agricultural use.11California Legislative Information. California Code Government Code 51238.1 Each county writes its own compatibility rules, so a use that one county permits may not be allowed next door.
Solar is the most common flashpoint. The Williamson Act itself says nothing about solar installations, so the decision falls to the local jurisdiction. A county can approve a solar project on contracted land if it finds the panels would displace only a small portion of current or reasonably foreseeable agricultural activity on the parcel.12California Department of Conservation. Solar Power and the Williamson Act The county has to build a solid written record for that finding, because neighboring landowners have legal standing to sue over compatibility decisions. Agrivoltaic designs that keep grazing or crops going underneath the panels stand on much stronger ground than projects that take acreage out of production entirely.
Buying or Selling Contracted Land
You can sell contracted property at any time, but the restrictions ride along with the deed. The buyer inherits the same obligations for whatever time remains on the clock.4California Department of Conservation. Land Conservation (Williamson) Act The restricted assessment and development limits usually depress the sale price compared to unencumbered land, which is part of the economic tradeoff of the program.
Subdivision is heavily restricted, with narrow exceptions. You can transfer a portion of contracted land to an immediate family member (spouse, parent, sibling, or child) if the resulting parcel meets the 10-acre prime or 40-acre non-prime minimum, conforms to local zoning, and is covered by a written joint-management agreement for the rest of the term. A separate carve-out allows sale or lease of up to five acres to a nonprofit, city, county, or other government agency.5Justia. California Code Government Code 51230-51239 – Agricultural Preserves
Getting Out of a Contract
There are three exit routes, and none of them is quick or cheap.
Nonrenewal
The normal way out is filing a notice of nonrenewal. Either you or the local government can file one. Once it takes effect, the contract stops auto-renewing and begins a nine-year countdown for a standard contract or 19 years for an FSZ contract.13California Department of Conservation. Williamson Act Contract Removal All the restrictions stay in force during the wind-down. The assessment climbs gradually each year, reaching full market rate at expiration, so the tax benefit shrinks over time rather than disappearing in one jump.
Cancellation
Immediate cancellation skips the wait but faces a high bar. The governing body can tentatively approve it only if it finds the cancellation is either consistent with the purposes of the Act or in the public interest because other concerns substantially outweigh farmland preservation.14California Legislative Information. California Code Government Code 51282 A consistency-based cancellation requires a stack of additional findings (nonrenewal already filed, no gaps created in the development pattern, no suitable uncontracted land nearby, and more), and failing any one of them blocks the cancellation.
The financial sting is substantial. The board has to certify a cancellation fee of 12.5 percent of the property’s current unrestricted fair market value for a standard contract, or 25 percent for an FSZ contract.15California Legislative Information. California Code Government Code 51283 On a parcel appraised at $2 million, that is $250,000 for a standard contract. The fee is paid to the county treasurer and is designed to deter using the program as a parking spot for land awaiting a development offer.
Material Breach
If you build a commercial, industrial, or residential structure larger than 2,500 square feet that is not permitted under the contract or the Act, the local government can declare a material breach. This provision applies only to buildings permitted and constructed after January 1, 2004.16California Legislative Information. California Code Government Code 51250 The penalty runs 25 percent of the unrestricted fair market value of the affected land plus 25 percent of the value of the offending building and related improvements. If the county or city itself approved the building that turned out to violate the contract, it may cut the penalty by up to half based on the landowner’s level of fault, but it cannot drop below 12.5 percent of the combined land-and-improvements value.17California Department of Conservation. Williamson Act Program – Basic Contract Provisions
Why Some Counties Are Reluctant
The program originally came with state money attached. Because contracted land generated less property tax, the state made annual “subvention” payments to counties to cover part of the loss. Those payments were effectively eliminated in 2009 and have not been restored. Counties now absorb the full revenue hit, and some have responded by tightening eligibility standards or becoming less willing to approve new contracts. If you are applying in a county that has been slow to enroll new land, that pressure on the general fund is usually why.