Solano County Land for Sale

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

Land for sale in Solano County ranges from lots inside its seven cities to rural residential parcels and large agricultural holdings in the unincorporated county. Outside city limits, the county zoning code sets firm minimum lot sizes, from 2.5 acres in rural residential zones up to 160 acres in exclusive agriculture. Well and septic permits, Williamson Act contracts and, near the marsh, Suisun Marsh policies decide what you can actually build.

At a glance

Where to look in Solano County

Land listings in Solano fall into a few settings, each with a different set of rules:

• City lots. Parcels in Vacaville real estate, Fairfield real estate, Dixon real estate, Suisun City real estate, Benicia real estate, Vallejo real estate and Rio Vista real estate follow city zoning and usually connect to city utilities. Confirm with the city before relying on county rules.
• Valleys west of Fairfield and Vacaville. Green Valley real estate and the Suisun Valley area have rural residential and agricultural land. The county code has a Suisun Valley Agricultural district (A-SV-20) with its own standards, separate from the exclusive agriculture zones.
• Agricultural land in the valley and near Dixon and Elmira. Around Elmira real estate and Dixon, much of the unincorporated land is in exclusive agriculture zones with 20- to 160-acre minimums. For farm or vineyard buyers, see Solano County vineyards.
• Near the Suisun Marsh and the Delta. Land near the marsh may fall within the Suisun Marsh Primary or Secondary Management Area, and Delta-side parcels near Rio Vista bring flood and levee questions. See Solano waterway and flood records and Rio Vista flood, levee and insurance records.

For a wider look at the county’s towns and housing types, see the Solano County where-to-live guide.

What to check before you buy

Zoning and minimum lot size

Solano’s zoning code (Chapter 28) states minimum lot areas directly in the district name. Exclusive Agricultural districts run A-20, A-40, A-80 and A-160, matching 20, 40, 80 and 160 acres. Rural Residential districts run RR-2.5, RR-5 and RR-10. The Suisun Marsh Agricultural districts are A-SM-80 and A-SM-160 (Solano County Code, Article II). A 40-acre parcel zoned A-40 can’t be split under that zoning, and a 7-acre parcel in RR-5 can’t be split into two lots without a change.

Ask whether the parcel is a legal lot. The county’s zoning FAQ covers legal lots, subdivisions and allowed dwelling types; read it and call Planning Services before you assume a parcel from an old deed is buildable on its own (Look Up Zoning & FAQ).

Williamson Act contracts

Solano County uses Williamson Act contracts to keep farmland in agriculture in exchange for reduced property taxes. The county describes the contracts as running at least 10 years. It is not currently accepting new contracts, but it may approve boundary adjustments and replacement contracts. The county’s Uniform Rules, adopted May 22, 2012, cover allowed uses, subdivision, lot-line adjustments and incidental residential development, and they can be stricter than zoning. Check a parcel in the county GIS Parcel Viewer (Solano County Planning).

Statewide, the Department of Conservation says a contract is binding on all later purchasers, and cancelling a standard contract carries a fee of 12.5% of current fair market value (DOC Williamson Act FAQ). Read the recorded contract and the Uniform Rules before you plan a house or a split. More in our Williamson Act guide.

Wells

Solano County Environmental Health requires a permit to install, modify or abandon a water well, test hole, monitoring well or soil boring. Work follows the California Well Standards and County Code Chapter 13.10 (county well and septic program). The county’s Well Program page covers construction and destruction permits, water testing and records on existing wells. Ask the seller for the well log and recent water-quality and yield tests, and ask Environmental Health whether it has records for the parcel.

Septic

A septic system needs an Environmental Health permit to install, modify, repair or abandon. Alternative systems, used where site conditions are limiting, must be designed by a licensed civil engineer, certified engineering geologist or registered environmental health specialist, and they need an operation and maintenance permit before final approval. The State Water Board’s OWTS Policy took effect May 1, 2013, and the county reports its Local Agency Management Program was approved on August 19, 2016 (county program page). The Onsite Sewage Disposal Program page explains site evaluations and when one is required. On raw land, make a site evaluation a contingency. Our rural house infrastructure guide for Solano covers what to request.

Suisun Marsh

The Suisun Marsh Preservation Act of 1977 required local governments with jurisdiction over the marsh to adopt a Local Protection Program. Solano County’s component, certified by BCDC in 1982 and amended in 1999, lives in the county General Plan. It divides the area into a Primary Management Area (tidal and seasonal marshes, managed wetlands and lowland grasslands) and a Secondary Management Area (upland grasslands and cultivated land that buffer the marsh). Dredging, filling or diking in the Primary Management Area needs approval from the appropriate permitting authorities (BCDC). If a parcel is near the marsh, ask county planning which area it is in before you plan improvements.

Fire Safe roads and access

The State Minimum Fire Safe Regulations (14 CCR 1270 et seq.) cover new residential, commercial and industrial buildings in the State Responsibility Area approved after January 1, 1991, and in Very High Fire Hazard Severity Zones approved after July 1, 2021. They also cover new parcels, use permits and new roads (14 CCR 1270.03). Hillside land in the county may be affected, so confirm the parcel’s fire responsibility area and hazard zone early. See fire hazard severity zones in the North Bay.

Road access and shared roads

Many rural parcels are reached by private roads or easements. Under Civil Code 845, easement owners must keep a private right-of-way in repair and, absent a written agreement, share the cost in proportion to use (text via california.public.law). Get the recorded easements from your preliminary title report and ask whether a road maintenance agreement exists. See private road maintenance agreements in California and our Solano ownership responsibility checklist.

How we approach a land purchase

1. Confirm whether the parcel is in a city or the unincorporated county, then read its zoning district and minimum lot size.
2. Check Williamson Act status and, near the marsh, management area.
3. Make septic site evaluation, water supply and access review contingencies.
4. Talk with Planning Services before removing contingencies if you plan to build, split or change use.

Our guide to buying land in California covers the full sequence, and our Solano County buyer page explains how we work with buyers.

Questions people ask

What is the smallest rural lot allowed in unincorporated Solano County?

In the Rural Residential districts the minimums are 2.5, 5 and 10 acres (RR-2.5, RR-5, RR-10). Residential Traditional Community districts allow smaller lots in established communities.

What does A-40 zoning mean in Solano County?

It is an Exclusive Agricultural district with a 40-acre minimum lot area. The number after "A" is the minimum lot size in acres.

Can I build a house on agricultural land?

Agricultural districts allow some residential use, but conditions depend on the district and, for contracted land, on the county’s Williamson Act Uniform Rules, which address incidental residential development. Ask Planning Services about the specific parcel.

Can I put new land under a Williamson Act contract?

Solano County says it is not currently accepting new contracts, though boundary adjustments and replacement contracts may be approved.

Do I need a permit to drill a well?

Yes. Environmental Health issues well permits under the California Well Standards and County Code Chapter 13.10.

Who designs a septic system on a difficult site?

Alternative systems must be designed by a licensed civil engineer, certified engineering geologist or registered environmental health specialist, and they need an ongoing operation and maintenance permit.

What is the Suisun Marsh Primary Management Area?

It covers tidal and seasonal marshes, managed wetlands and lowland grasslands. Filling, dredging or diking there needs approval from the permitting authorities.

Who pays to maintain a private road?

Without a written agreement, Civil Code 845 has easement users share repair costs in proportion to use.

Sources & notes

1. Solano County Code, Chapter 28, Article II, Districts and Allowable Uses (Code Publishing, the county’s code host).
2. Solano County Planning Services, Look Up Zoning & FAQ.
3. Solano County Planning Services, Agricultural Preserves/Williamson Act Contracts.
4. Solano County Environmental Health, Well Program and Onsite Sewage Disposal Program.
5. Solano County Environmental Health, Well & On-site Sewage Disposal Program (county program page).
6. BCDC, Solano County Component of the Suisun Marsh Local Protection Program.
7. California Code of Regulations, Title 14, § 1270.03.
8. California Department of Conservation, Williamson Act FAQ (2024).
9. California Civil Code § 845 (text via california.public.law).

Notes: The county’s Williamson Act page gives a 10-year minimum contract term; the state FAQ describes the statewide minimum as nine years. Read the recorded contract for the term that applies. Minimum lot sizes for Watershed and other districts were not confirmed for this page. No prices or market figures.

General information, not legal, tax or lending advice. Updated November 2026. Primary sources are linked in this guide.

Related: Solano County real estate · Where to live in Solano County · Buying land in California · Private road maintenance agreements · Solano rural house infrastructure