Commercial Real Estate in Byron: Airport Land, Agricultural Business and County Rules

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

Byron is a small unincorporated farm town in far eastern Contra Costa County, between Brentwood, Discovery Bay and the Alameda County line. Its commercial property is a short main street and highway frontage along Byron Highway and Camino Diablo, agricultural processing and farm businesses, and the county-owned Byron Airport. The airport now has the county’s largest planned pool of business land in East County. All land use here is decided by Contra Costa County, so confirm zoning, airport compatibility and utility service before you commit.

Who controls the parcel

There is no city. Contra Costa County’s Department of Conservation and Development applies county zoning, and the county also owns and runs Byron Airport. Special districts on Contra Costa LAFCO’s roster for the area include:

Byron Sanitary District. Formed in 1948, it provides sewage collection, treatment and disposal for the Byron community, about 0.53 square miles with roughly 800 residents, according to LAFCO’s sanitary district directory. A five-member board elected at large governs it. Properties outside the district rely on septic.
Byron Bethany Irrigation District, which supplies agricultural water.
Reclamation District 800 (Byron Tract), which maintains levees and drainage on the Delta side.

Byron is outside the cities of Brentwood and Discovery Bay. Discovery Bay is an unincorporated community with its own services district.

Byron zoning for commercial, industrial and agricultural business

District or plan	Intended uses	Notes
Byron Airport, Planned Unit District (P-1) under the 2022 Airport Development Program	Aviation uses plus light industry, warehousing and distribution, commercial and retail, and offices	Airport land use compatibility rules apply
Agricultural districts (A-2, A-3, A-4, A-20, A-40, A-80)	Farming, agricultural processing and agritourism allowed by the county code	Most land around the town
County commercial districts (N-B, R-B, C)	Neighborhood and general commercial uses	Confirm which is mapped on the town’s commercial blocks
Small wineries (Chapter 824-6)	Wine production and tasting	Up to 50,000 gallons a year. 5,000 sq ft production cap. Tasting area no more than 30% of production floor

Our Contra Costa County commercial page explains the county’s commercial and industrial district standards. The district on any Byron parcel has to be read from the county zoning map, and many parcels are agricultural.

Byron Airport: the main business land

Background. The county’s 2005 airport master plan describes a general aviation airport of about 1,307 acres, roughly midway between Byron and the Alameda County line. It has two runways, 4,500 feet and 3,000 feet long. The airport was sited partly to relieve aircraft demand at Buchanan Field in Concord. The plan reserved about 125 acres east of the airfield for nonaviation, airport-related uses such as commercial, multimodal and warehouse facilities, and about 96 acres west of the airfield for an FBO and corporate hangars. It noted that the airport lies inside the county’s urban limit line, with surrounding private land designated agricultural.

2022 Development Program. The county’s Byron Airport Development Program page says the Board of Supervisors adopted the program on June 7, 2022. It amended the Airport Land Use Compatibility Plan, the General Plan and the airport’s planned unit zoning, which had blocked most uses the airport needed to become self-sufficient. The county says the changes substantially broaden the uses allowed by right. The program’s environmental notice on CEQAnet covered 1,427 acres near Armstrong Road and Falcon Way. It studied up to 835,000 square feet of development: about 186,000 sq ft of office, 248,000 sq ft of commercial and 392,000 sq ft of industrial space. Airport-compatible uses named include light industry, warehousing and distribution, general commercial and retail, and offices, alongside hangars, fixed-base operators and aircraft sales.

Airport land is county-owned, so businesses generally lease ground or buildings from the county rather than buy fee title. Contact the county’s airports division about leasing.

Agricultural business, wineries and rural constraints

Wineries. Under Chapter 824-6, a small winery may produce up to 50,000 gallons a year, with production space capped at 5,000 square feet and tasting and sales space at 30% of the production floor. At least 25% of the fruit must be grown on the premises and 50% in Contra Costa County. Food at tastings must be incidental, served as small fixed-menu appetizers that are not sold separately. The winery needs an ABC 02 winegrower license, and other ABC license types are prohibited.
Airport compatibility. Parcels near the airport are subject to the Byron Airport Land Use Compatibility Plan. The plan’s safety zones can limit people-intensive uses and building heights on private land around the field.
Water and sewer. Outside the sanitary district, a business needs septic approval from county environmental health and a well or other water source. Farm water typically comes through the irrigation district, not a potable system.
Urban limit line. Land outside the county’s urban limit line faces sharp limits on urban uses. Check where any edge parcel falls.

Transfer tax, business tax and property tax

The Contra Costa Clerk-Recorder charges the county documentary transfer tax of $0.55 per $500. Byron is unincorporated, so no city transfer tax applies. A sale is generally a Proposition 13 change of ownership. Farmland may be under a Williamson Act contract, which lowers assessments but restricts uses. Airport ground leases may create a possessory interest tax. We did not verify a county business license requirement.

Due diligence that matters in Byron

Start with our commercial due diligence checklist, then add:

Pull the county zoning and General Plan designations and check the urban limit line.
Check the parcel against the Byron Airport compatibility zones.
Confirm Byron Sanitary District service, or septic feasibility outside it.
Identify the water source and any irrigation district or reclamation district charges.
Check for a Williamson Act contract on agricultural land.
For airport sites, review the ground lease term, rent escalations and county development standards.

Questions people ask

Who regulates land use in Byron?

Contra Costa County. Byron is unincorporated, so county zoning applies.

What can be built at Byron Airport now?

The county’s 2022 program broadened by-right uses to include light industry, warehousing and distribution, commercial and retail, and offices, plus aviation businesses. Its environmental study looked at up to 835,000 square feet.

Can I buy land at Byron Airport?

The airport is county-owned. Businesses generally lease from the county. Contact the county airports division about availability.

Does Byron have sewer service?

The Byron Sanitary District serves the Byron community of about half a square mile. Rural parcels outside it use septic.

Can I open a tasting room near Byron?

A small winery can include tasting space up to 30% of its production floor, with fruit sourcing rules and a 50,000-gallon cap.

Is there a city transfer tax?

No. Only the county tax of $0.55 per $500 applies.

Does Diamond handle commercial property in Byron?

Contact Matthew Martinez to discuss buying, selling or leasing commercial property in Byron.

Sources & notes

Note: The zoning of Byron’s main street parcels was not confirmed on the county map. The Byron Airport compatibility plan zones and the final adopted development cap were not opened.

This page is general information, not legal or tax advice. Last reviewed October 2026 by Matthew Martinez.

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