California Williamson Act

Content provided for general information. Talk to your advisor to confirm the details for your specific situation before taking action.

The Williamson Act provides a tax break for landowners who maintain their properties for agricultural or open space uses.

What does the Williamson Act do?

The Williamson Act (California Land Conservation Act of 1965) is California’s version of the cow property tax exemption available in many states. However, the rules are much stricter in California than in many other places.

Properties with a Williamson Act contract are generally valued based on their use as agricultural land. This is often much lower than the fair market value of land held for building houses or commercial uses.

What qualifies for the Williamson Act?

While the exact requirements vary by county, the general rules are that you need to have at least ten acres of prime agricultural land or 40 acres of non-prime agricultural land.

You also generally need to be using all or nearly all of the party for productive agricultural purposes. A property held as an agricultural preserve or other qualified open space can also qualify.

In order to enroll in the Williamson Act Program, you generally need to sign a contract for at least ten years. Williamson Act contracts automatically add on one additional year every year so they always remain valid for ten years.

If you want to leave the Williamson Act program, you have to give a notice of non-renewal. Your contract will then stop automatically renewing, and you’ll generally be able to exit the program after about ten years (plus or minus a few months depending on the timing of your notice).

There are limited hardship and public interest exceptions that may allow you to leave your Williamson Act contract early. You generally don’t have a right to cancel the contract simply by repaying the tax savings.

What is prime versus non-prime land?

Prime versus non-prime land definitions may vary by county.

Prime land is generally land that is more productive in terms of what you grow on it and the income it produces.

Non-prime land is all other land.

Contact your county property tax assessor for your specific local rules.

What do you need to do to apply?

In order to apply, you will need to request an information packet from your local property assessor. The packet will contain the specific rules for your county, application forms, and the contract.

You will need to submit the following:

  • Proof that you own the parcel and that it’s a suitable size

  • Proof of your agricultural use, such as a site plan

  • Proof that you’re earning income from the parcel, such as a tax return

The exact documentation you’ll need will depend on where you are and your specific land use. If you need help, chat with a tax expert online.

Can I build a house on Williamson Act land?

There are generally two ways you can build a house on Williamson Act land.

  • At least 90% of the parcel must be in productive agricultural use. It also generally needs to have an independent source of irrigation, although contracts to use other water sources may be enough.

  • The parcel includes a confined animal facility such as a commercial dairy, cattle feedlot, poultry operation, or commercial aquaculture facility.

These rules are designed to limit the tax break to actual farming uses or open space lands. California doesn’t want private landowners gaming the tax system by saying they’re “farming” by having a few cows on their parcels.

What is the Williamson Act tax rate?

There is no special tax rate under the California Land Conservation Act. The benefit is having lower property tax assessments due to the property being valued at its agricultural value rather than its full market value for all uses.

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