Commercial Real Estate in Bethel Island: Marinas, Levee Rules and County Zoning

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

Bethel Island is an unincorporated Delta island in eastern Contra Costa County. Its commercial property is mostly marinas, boat sales and storage yards, bait shops, bars and restaurants, RV parks and a small cluster of service businesses along Bethel Island Road. The island sits below sea level behind a levee, so commercial use here depends on county zoning, levee district approvals and utility access more than on market demand. Confirm all three for any parcel before you make an offer.

Who controls the parcel

There is no city on Bethel Island. Land use is governed by Contra Costa County’s Department of Conservation and Development under Division 84 of the County Ordinance Code. Several special districts also have a say:

Bethel Island Municipal Improvement District (BIMID). The Legislature created it in 1960 to replace a reclamation district formed in 1915. Contra Costa LAFCO’s service review describes about 3,500 acres of reclaimed land, more than 95% below sea level, ringed by an 11.5-mile levee. BIMID says it must approve any project that affects the levee, including construction, docks, ramps, levee steps, tree planting and demolition.
Ironhouse Sanitary District provides sewer service across the island, per the LAFCO review.
Water is a patchwork. Diablo Water District serves Delta Coves and Beacon West. County Service Area M-28 serves the Willow Park Marina area. Most other properties use private wells or one of about 30 small private water companies.
State and federal agencies may also be involved. Work in or over the sloughs can need permits from them. Ask the county which apply to your site.

Bethel Island zoning for commercial and marine use

District	Intended uses	Notes
F-1 Water Recreational	Single-family homes, farming, private docks with up to two berths	Commercial boat harbors need a land use permit. 50 ft setback from a levee centerline
C General Commercial (where mapped or rezoned)	Retail, wholesale, warehouses, auto and boat repair, contractor yards	Countywide district. The 2008 Pacific Boat Center request sought C/FH zoning here
-FH Flood Hazard combining	Overlay on base zones in special flood hazard areas	Elevated homes may reach 3½ stories if the lowest level is parking, storage or access only
-BS Boat Storage combining	Boat storage overlay	Chapter 84-78
T-1 Mobile Home Park	Mobile home, travel trailer and RV parks and campgrounds	Land use permit. 3 acre minimum, 12 units per acre

The table lists districts we confirmed for the island or its code chapters. Other county commercial districts are summarized on our Contra Costa County commercial page. The district on any one Bethel Island parcel has to be read from the county zoning map.

What business uses are realistic on the island

Marinas and harbors. F-1 is the zone that runs along much of the waterfront. A homeowner can have a private dock with up to two berths, as long as each has sanitary facilities and two parking spaces. A commercial boat harbor needs a county land use permit. So buying a waterfront F-1 lot to open a public marina means a discretionary permit, not an over-the-counter approval.

Rezoning for commercial use. A 2008 county filing on CEQAnet shows how this works. The owner of an 8.68-acre parcel at Bethel Island Road and Taylor Road applied to rezone from F-1/FH to C/FH (General Commercial with flood hazard). The plan was boat, RV and vehicle sales, service and storage with a 6,000 sq ft building, reviewed under a mitigated negative declaration. The filing notes the general plan designation was already commercial. When zoning and the general plan disagree, a rezoning backed by the general plan is the usual path.

Long-range plans. The county’s Bethel Island Area Specific Plan draft EIR, filed in 1989 (CEQAnet), looked at 7,000 acres across Bethel Island and Hotchkiss Tract. It considered up to 100,000 sq ft of recreation-related commercial space, 500 hotel rooms and marinas. That plan shows the island’s intended resort and marine character. Check with the county whether any part of it is in force today.

Levee, flood and utility constraints

Levee setback. F-1 requires buildings to stay at least 50 feet from the centerline of any nearby levee, unless the zoning administrator grants a variance.
BIMID approvals. Under BIMID Ordinance 18 (2006), a district permit for building, alteration or grading that needs a variance is put on hold until a variance application is filed. The board weighs peat compression, seepage and levee access. A granted variance lapses if work does not start within one year.
Flood. With the island below sea level, most sites are in special flood hazard areas. County floodplain rules (Chapter 82-28) require elevated buildings. The LAFCO review notes BIMID reports the levee meets FEMA standards, while long-term levee funding is unresolved.
Water quality. LAFCO reports that island groundwater is often high in iron, manganese and dissolved solids, and some wells exceed the arsenic standard. A restaurant or RV park on a private well may need treatment and a state or county water system permit.
Cannabis. Bethel Island is one of nine areas in the county’s -CE Cannabis Exclusion district, which prohibits commercial cannabis activity in every zone.

Transfer tax, business tax and property tax

The Contra Costa Clerk-Recorder charges the county documentary transfer tax of $0.55 per $500. With no city, there is no city transfer tax. A sale is generally a Proposition 13 change of ownership. BIMID is funded partly from county-collected property taxes, so check the tax bill for any district levies. We did not verify a county business license requirement for unincorporated Bethel Island.

Due diligence that matters in Bethel Island

Start with our commercial due diligence checklist, then add:

Pull the county zoning and general plan designations, including any -FH or -BS overlay.
Confirm existing marina, harbor or RV park use permits and their conditions.
Get BIMID’s position on any work near the levee, and measure the 50-foot setback.
Order a flood elevation certificate and quote flood insurance.
Identify the water source and test it. Confirm Ironhouse sewer capacity.
Review dock and berth permits with state and federal agencies.

Questions people ask

Who approves a business on Bethel Island?

Contra Costa County, under county zoning. BIMID must also approve anything that affects the levee.

Can I open a marina in the F-1 zone?

A commercial boat harbor is allowed in F-1 with a county land use permit. Private docks are limited to two berths.

How close to the levee can I build?

F-1 requires at least 50 feet from the levee centerline, unless the zoning administrator grants a variance.

Is cannabis allowed on Bethel Island?

No. Bethel Island is in the county’s cannabis exclusion district, which bans commercial cannabis in every zone.

Who provides sewer and water?

Ironhouse Sanitary District provides sewer. Water comes from Diablo Water District, CSA M-28, private wells or small private water companies, depending on location.

Is there a city transfer tax?

No. Bethel Island is unincorporated, so only the county tax of $0.55 per $500 applies.

Does Diamond handle commercial property in Bethel Island?

Contact Matthew Martinez to discuss buying, selling or leasing commercial property on Bethel Island.

Sources & notes

Note: The LAFCO service review predates current population figures. The status of the 1989 specific plan and the outcome of the 2008 rezoning were not confirmed.

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

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