Byron CA Real Estate & Homes For Sale

Where Byron is and who governs it

Byron is an unincorporated community in far eastern Contra Costa County, on both sides of Byron Highway near Camino Diablo. There is no city government. Contra Costa County’s Department of Conservation and Development handles zoning, land-use permits and building permits, and county code applies to every Byron parcel. Mailing addresses use the 94514 ZIP code, as shown in county environmental filings for Byron projects.

The county’s 2045 General Plan, sets land-use designations. Contra Costa’s voter-approved Urban Limit Line, first set by Measure C in 1990, marks the boundary beyond which no urban land uses can be designated. Much of the land around Byron is agricultural, so a buyer’s first question is often which side of that line a parcel sits on, and what its zoning allows.

Water, sewer and utilities in Byron

• Sewer in the community core: Byron Sanitary District, formed in 1948, collects, treats and disposes of wastewater for the unincorporated community of Byron. It covers fewer than 250 acres along Byron Highway at Camino Diablo, so confirm whether the actual parcel is within its boundary and connected.
• Wells and septic outside the core: Confirm the actual drinking-water and wastewater arrangements for each rural parcel. One county-reviewed two-lot subdivision on Bixler Road planned water from two existing domestic wells permitted by Contra Costa Environmental Health, plus a new septic system for each future home. Contra Costa Environmental Health requires a permit to construct, rebuild or destroy a well. Ask for well permits, the driller’s report, recent water tests and septic records.
• Irrigation: Byron-Bethany Irrigation District is a multi-county district that serves agricultural land in eastern Contra Costa (about 10,291 acres of its boundary is in the county), according to Contra Costa LAFCO’s 2026 public-review draft service review. Irrigation service is separate from domestic drinking water. Confirm whether a parcel is in the district and what deliveries it has.

Homes, lots and land use in Byron

Byron combines a small community core, including commercial parcels near Byron Highway and Camino Diablo, with large agricultural parcels. County review of the Byron Corners project at 15031 Byron Highway shows how mixed the designations can be there: the site is zoned for general agriculture and retail business, with a high-density single-family General Plan designation.

Many farm parcels are enrolled in the Williamson Act, which Contra Costa has administered since 1968. A contract is an enforceable restriction that binds future owners. It runs at least ten years and renews automatically each year unless nonrenewal is filed. Ask the Assessor to explain the parcel’s current restricted assessment under the applicable valuation rules. Ask whether a parcel is under contract before planning non-farm uses. See our guide to buying land in California.

For an ADU, use the County’s 2025 ordinance record as a starting point and ask Planning which current local standards and state pathway apply. Confirm actual utility connections or private-system capacity for the proposed use; a rural address alone does not determine eligibility.

Hazards and insurance to check

• Wildfire: Grass and brush fires happen in the east county hills. Look up the parcel in the State Fire Marshal’s Fire Hazard Severity Zone maps. Many rural parcels are in the State Responsibility Area, where maps took effect April 1, 2024. Get insurance quotes early.
• Flood: Low-lying parcels toward the Delta should be checked on FEMA’s Flood Map Service Center.
• Airport: Byron Airport, owned by the county since 1993 and dedicated in 1994, is about 3 miles south of Byron. Its 1,307-acre site includes 814 acres of habitat management land. Properties nearby may carry an airport-influence disclosure.

Getting around from Byron

Byron Highway runs north–south through the community and connects toward State Route 4 and Brentwood. Vasco Road leads south toward Livermore. Driving is the norm for commutes and errands, and rural parcels may depend on private roads or recorded access easements. Ask for those documents.

Local rules buyers and owners should know

• Short-term rentals: Unincorporated Contra Costa County requires a short-term rental permit. The County summary gives a 90-day non-hosted limit under the ministerial path and a discretionary pathway for specified deviations. Check all permit conditions; the operational prohibition on ADU short-term rentals remains.
• Taxes: Check the parcel’s actual bill for special assessments. For Williamson Act land, ask the assessor how the restricted value is calculated. See our Contra Costa County property tax guide.

Byron real estate: questions people ask

Is Byron a city?

No. Byron is unincorporated Contra Costa County, so county planning, building and code enforcement apply. Byron Sanitary District serves the small community core with sewer. For a rural parcel, confirm actual service connections and any private well or septic permits with the providers and Environmental Health.

Do Byron homes have public water and sewer?

It depends on the parcel. Byron Sanitary District covers fewer than 250 acres around Byron Highway and Camino Diablo. Outside it, confirm the actual water source and wastewater arrangement rather than assuming either. Ask for the well permit, the driller’s report, a recent bacteria test and septic records before removing contingencies.

Can I build a second home on Byron farmland?

Not automatically. The answer depends on the parcel’s zoning, its General Plan designation, its location relative to the Urban Limit Line, and whether it is under a Williamson Act contract. Septic and well capacity also limit what can be added. Ask Contra Costa County planning for a parcel-specific answer before you buy.

What should I check near Byron Airport?

Read the Natural Hazard Disclosure and any airport-influence disclosure. Ask the county how the airport’s land-use compatibility rules apply to the parcel. The airport is about 3 miles south of Byron and owned by Contra Costa County, so its plans are a county matter.

Compare nearby areas: Knightsen real estate, Discovery Bay real estate, Brentwood real estate, and unincorporated Contra Costa County.

Sources for this section

1. Contra Costa County, Envision Contra Costa / 2045 General Plan and Urban Limit Line: https://www.contracosta.ca.gov/6970
2. Contra Costa Special Districts Association, Byron Sanitary District profile: https://contracostasda.specialdistrict.org/byron-sanitary-district
3. CEQAnet, Two-lot minor subdivision, Byron (CDMS20-00001): https://ceqanet.lci.ca.gov/2021110086
4. CEQAnet, Byron Corners General Plan Amendment and Rezone: https://ceqanet.lci.ca.gov/2023040498
5. Contra Costa Health, current Land Use Program — https://www.cchealth.org/health-and-safety-information/orders-and-regulations/land-use-program
6. Contra Costa LAFCO, Countywide Water and Irrigation Districts MSR, public review draft (July 2026): https://www.contracostalafco.org/wp-content/uploads/2026/07/04.-070826-Item-7.-MSR-draft-1-WaterIrrDist.pdf
7. Contra Costa County, Williamson Act: https://www.contracosta.ca.gov/4338/Williamson-Act
8. CEQAnet, Contra Costa County Ordinance 2025-07 (ADUs): https://ceqanet.lci.ca.gov/2025050593
9. Office of the State Fire Marshal, Fire Hazard Severity Zones: https://osfm.fire.ca.gov/what-we-do/community-wildfire-preparedness-and-mitigation/fire-hazard-severity-zones
10. FEMA Flood Map Service Center: https://msc.fema.gov/portal/home
11. Contra Costa County, Airports History: https://contracosta.ca.gov/3932/Airports-History
12. Contra Costa County, Short-Term Rentals and ordinance summary: https://www.contracosta.ca.gov/10303/Short-Term-Rentals ; https://www.contracosta.ca.gov/10609