Sonoma & Marin Ranch Real Estate Glossary

20 terms · Definitions are general references, not legal advice. Verify against current statute and recorded deed before relying on any term for a transaction decision.

A-20 / A-40 / A-60 zoning

Sonoma and Marin County agricultural zoning categories. The number generally relates to minimum parcel-size and density standards, but buildability depends on the parcel, zoning district, coastal status, septic, access, slope, easements, and current county rules. In Marin, A-60 applies to many inland agricultural parcels, while C-APZ (Coastal Agricultural Production Zone, Marin Title 22 under the Local Coastal Program) governs many coastal-facing agricultural lands west of Highway 1. In Sonoma, A-20, A-40, LIA, DA, and related districts all require parcel-specific review.

ADU (Accessory Dwelling Unit)

A secondary residence on a single parcel. California ADU law has changed materially, but agricultural-zoned parcels under conservation easement, Williamson Act contract, coastal rules, septic limits, or other recorded restrictions may still face limits. Always check the parcel documents and current county rules before assuming ADU rights.

Appropriative water right

A water right based on first use and continued beneficial use, regardless of where the water comes from in relation to the land. In California, post-1914 appropriative rights are administered by the State Water Resources Control Board. Senior (older) rights have priority over junior (newer) rights in a drought year.

Baseline Documentation Report (BDR)

A photographic and narrative record of a property's condition at the time a conservation easement is recorded. The BDR is a key reference for future monitoring, and departures from the documented baseline can raise easement-compliance questions. Buyers of easement-encumbered land should obtain and review the BDR before closing.

Building envelope

A mapped area within a conservation-easement parcel where specified structures may be permitted. The recorded easement deed and Baseline Documentation Report control what can be built, where, and under what approval process. Any change outside the approved envelope should be reviewed with the easement holder before a buyer relies on it.

Coastal Commission permit

A development permit required for many types of construction, grading, subdivision, or significant use changes within the Coastal Zone. The Coastal Zone extends inland varying distances from the Pacific, and jurisdiction may involve the county, a certified Local Coastal Program, and appeal rights to the California Coastal Commission. Permit timing depends on the parcel, proposal, completeness of application, and agency review.

Conservation easement

A recorded deed restriction that permanently limits development rights on a property in exchange for tax benefits and (often) cash to the original grantor. The easement runs with the land — every future owner is bound. Common easement-holders in this region: MALT (Marin Agricultural Land Trust), Sonoma Land Trust, Sonoma Ag + Open Space District.

DRE (California Department of Real Estate)

The state agency that licenses California real estate brokers and salespersons. Karl Bundesen holds DRE License #00902729; DRE public records show salesperson licensure issued in 1985 and broker licensure issued in 1989.

FAIR Plan (California FAIR Plan)

A California insurance option often used when standard-market property coverage is not available. Coverage, premium, companion-policy needs, and lender acceptance depend on the property, structures, fire-risk profile, and current insurance market. Buyers should obtain bindable quotes before removing contingencies.

LCP (Local Coastal Program)

The county-level land-use plan certified by the California Coastal Commission that governs development within the Coastal Zone. Marin's LCP and Sonoma's LCP have different parcel-specific overlays, density caps, and habitat-protection layers that materially affect what can be built.

MALT (Marin Agricultural Land Trust)

A private nonprofit founded in 1980 that purchases agricultural conservation easements on Marin County ranches. MALT easements commonly restrict subdivision and non-agricultural development rights permanently, in exchange for an easement-purchase payment to the original landowner. As of May 2026, MALT reports 98 easements protecting 58,917 acres in Marin County.

Mandatory Agricultural Use (MAU)

A covenant within some MALT easements that requires the property to be in commercial agricultural production on an ongoing basis, with annual reporting to the land trust. MAU goes beyond the standard conservation easement: a recreational-use buyer or hobby-farm buyer cannot satisfy MAU.

Permitted Use Request (PUR)

The formal application a MALT-eased landowner submits to propose any new structure, road, fence line, or use change beyond what's already approved in the easement deed and Baseline Documentation Report. Review timing depends on the recorded easement, the proposal, and MALT's process.

Petaluma Gap AVA

The Petaluma Gap American Viticultural Area, federally recognized by the TTB in 2017. The AVA spans approximately 202,476 acres across southern Sonoma and northern Marin counties; the defining feature is the marine fog and afternoon wind that funnel through the gap between Tomales Bay and San Pablo Bay.

Pre-1914 water right

A surface-water claim based on use that predates California's modern appropriative-right permitting system. Pre-1914 rights generally do not require a SWRCB permit or license, but they remain subject to reasonable-use limits, reporting rules, public-trust considerations, curtailment risk, and fact-specific proof. Check recorder records, historic diversion evidence, and SWRCB reporting before relying on a pre-1914 claim.

Riparian water right

A water right held by the owner of land contiguous to a stream or watercourse. The right is appurtenant to riparian land — it transfers automatically with the parcel when the land is sold, but cannot be severed and sold separately from the riparian land. Rights are correlative: co-riparians on the same watercourse share the natural flow on a reasonable-use basis rather than by first-in-time priority. Riparian rights are the most common surface-water claim in Sonoma and Marin.

ROFR (Right of First Refusal)

A clause — found in some conservation easements and in certain Sonoma County ag-protection programs — that gives the easement holder or a designated agricultural buyer the first opportunity to purchase the property if the owner sells. ROFR language can affect escrow timing and buyer strategy. Read the easement deed for ROFR language before submitting an offer.

SGMA (Sustainable Groundwater Management Act)

California's 2014 groundwater law. Covered basins have a Groundwater Sustainability Agency (GSA) that adopts a Groundwater Sustainability Plan and may impose registration, reporting, metering, allocation, or pumping-fee requirements. Petaluma Valley, Sonoma Valley, and Santa Rosa Plain rules should be checked by basin and year before a buyer relies on well-water assumptions.

Williamson Act

California Land Conservation Act of 1965 (Govt Code §§51200–51297). A voluntary rolling property tax contract between a landowner and the county. The owner agrees to keep the land in agricultural production, and the assessor generally values the land using agricultural-use rules rather than unrestricted market value. Compatible uses, non-agricultural footprint limits, nonrenewal, and cancellation consequences depend on the recorded contract, county rules, and current law.

---

Missing a term you wish were here? Email Karl — useful additions get added.