Will They Build on That Field? Brentwood's Farmland Rules

It is the single most common question I get on a showing, and it almost never comes out as a question about zoning. It comes out as, "That's pretty. Is it going to stay?"

Fair thing to ask. You are looking at a row of peach trees or a vineyard from a back patio you are about to pay for, and you want to know whether you are buying a view or a construction site. After more than 30 years working Contra Costa transactions, first in lending and title and now in sales, this is the answer, and where you can look it up yourself.

What is Brentwood's Agricultural Core?

The City of Brentwood describes an 11,000-acre "Agricultural Core" surrounding the city, and it is not marketing language. It is a planning designation that shapes what can and cannot be built.

Two things make that farmland unusually durable. First, the soil is productive; the city calls it some of the most fertile in California. Second, and this is the part almost nobody knows, most of those 11,000 acres are irrigated by a local district holding a pre-1914 water right, which means a more reliable and more affordable water supply than newer rights allow. Land with senior water is land that keeps farming.

The city puts money behind it

Through the Agricultural Enterprise program it created in 2001, the city reports contributing more than $12 million toward easements that have permanently preserved 988 acres of local farmland, working with partners like the California Farmland Trust.

The Agricultural Core by the numbers

• 11,000 acres — the Agricultural Core surrounding Brentwood, per the City
• Pre-1914 — the seniority of the water right irrigating most of that acreage
• 2001 — the year the city created its Agricultural Enterprise program
• $12 million+ — city contributions toward conservation easements to date
• 988 acres — local farmland permanently preserved through those easements
• One acre — the conversion threshold that triggers Chapter 17.730

What does Chapter 17.730 require of a developer?

This is the mechanism, and it is worth understanding because it explains the pattern you see when you drive Brentwood: dense neighborhoods that stop, abruptly, at a row of trees.

Under Brentwood Municipal Code Chapter 17.730, the city must require agricultural preservation from any applicant seeking a subdivision or other discretionary land use entitlement that would permanently convert more than one acre of agricultural land to a non-agricultural use. The applicant satisfies it one of two ways:

• Grant an agricultural conservation easement on farmland the city finds acceptable. The easement has to encumber the exact acreage of the proposed project, including land used for parks and recreation.
• Pay an in-lieu fee set by City Council resolution. The code caps how fast that fee can climb: no more than a ten percent increase in any twelve-month period.

The easement itself is not a handshake. Section 17.730.060 requires a recordable instrument that prohibits any activity substantially impairing the land's agricultural productivity, and it requires the existing water rights to stay with the land. Protecting the water is what keeps the easement from becoming a technicality.

What is a "transfer of agricultural credit"?

You will hear the initials TAC at planning meetings. In short: certain farm parcels can generate development credits by locking themselves into a permanent easement, and those credits get transferred to a residential parcel elsewhere in the city, where the housing gets built.

The code draws the donor area with real boundaries — roughly 2,160 acres of the county Agricultural Core bounded by Marsh Creek on the west, the East Contra Costa Irrigation District Main Canal on the north, Sellers Avenue on the east, and Marsh Creek Road on the south. Eligible parcels over an acre earn two credits for each acre placed under permanent easement.

Why should a buyer care? Because it tells you the growth is designed to concentrate inward rather than march outward. That is a very different long-term picture than a town with no such rule.

What I check before I answer that question

This is where career matters more than opinion, and where I would rather show you than reassure you.

The other half of living next to working farmland is noise, dust, and spraying, and Brentwood addresses that head-on with a mandatory disclosure. If you are buying within 2,000 feet of agricultural land, you will be handed a Right to Farm acknowledgment, and it is worth reading rather than initialing. I wrote a full breakdown of it in Will farm noise wake me up? Brentwood's Right to Farm rule.

September is the month to go look at it

If you are weighing a move here, come in the fall and drive the farm trail. You will learn more in an afternoon than from any listing photo.

Harvest Time in Brentwood, the nonprofit growers' co-op, publishes a farm trail map covering more than 65 local growers who sell direct. Their fall lineup runs to pumpkin patches, corn mazes, and tractor rides at farms including G&S Farms, Smith Family Farm, and Three Nunns Farm. Opening weekends move year to year, so check the farm status page before you drive out rather than trusting last season's dates.

Two things happened in 2024 that changed how the rest of California sees this valley. Brentwood was recognized as the U-Pick Capital, on the strength of more than 60 family-owned farms — the city counts over 500,000 farm visitors a year. And the federal Alcohol and Tobacco Tax and Trade Bureau established the Contra Costa American Viticultural Area, so local wineries can now put "Contra Costa" on the label. For the vineyard rows you see from Trilogy at the Vineyards and the neighborhoods along Balfour, that is not a small thing. Recognition tends to make farmland more valuable as farmland, which is exactly the outcome the easement program is chasing.

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Send me the address and tell me which window the field is in. I'll pull the preliminary title report and the general plan designation for that parcel and tell you which one you are looking at, a recorded easement or a designation that could change someday, before you write on the house.

(925) 200-0717 — I answer my own phone, seven days a week, and I'd rather read the recorded instrument with you before the offer than after.

This post is for general informational purposes only and is not legal or tax advice. Land use designations, municipal code provisions, and recorded easements change over time and vary parcel by parcel. Confirm the status of any specific property with the City of Brentwood and through a current preliminary title report before relying on it in a purchase decision.

Margie Lupo, Broker Associate, SRES® · eXp Realty of Northern California, Inc. · DRE #01193496 · Brokerage DRE #02188495 · Equal Housing Opportunity

Sources

• City of Brentwood, Agritourism — Agricultural Core acreage, Agricultural Enterprise program, easement funding, pre-1914 water right, U-Pick Capital, Contra Costa AVA. Accessed September 2, 2026.
• Brentwood Municipal Code Chapter 17.730, Agricultural Preservation Program (Ord. 877 § 2, 2010) — easement and in-lieu fee requirements, transferable agricultural credits, easement terms. Accessed September 2, 2026.
• Harvest Time in Brentwood — grower co-op, farm trail map, fall harvest activities. Accessed September 2, 2026.