Commercial Real Estate in Penngrove: Main Street, the Penngrove Area Plan and Rural Business Uses

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

Penngrove is an unincorporated village between Petaluma and Rohnert Park, and its commercial property is small in scale: storefronts and offices on Main Street, service and feed businesses near the railroad and Old Redwood Highway, a few light industrial sites, and agricultural businesses in the surrounding hills. It is governed by Sonoma County and by its own adopted area plan, not by either neighboring city. Confirm zoning and plan designations with Permit Sonoma before relying on this page.

Who controls the parcel

Permit Sonoma applies the county zoning code to Penngrove, and the Penngrove Area Plan adds local land use policy. The plan was first adopted April 10, 1984 by Resolution 84-675 and was modified in 1993 (Resolution 93-0337) and on September 23, 2008 (Resolution 08-0808). New subdivisions and development must be consistent with the General Plan and any applicable area plan, according to Permit Sonoma. Utilities are split among special districts: the Penngrove Sanitation Zone for sewer, the Penngrove Water Company for much of the village’s water, and the Penngrove Fire District for hydrant and fire-flow rules within the water company area. For countywide context see our Sonoma County commercial guide.

Penngrove land use for commercial and industrial property

The area plan’s land use section defines the business designations used in Penngrove. Each parcel also carries a county zoning district, which you should confirm on the county’s parcel record.

Main Street and the village core

The plan’s stated aim is to keep Penngrove’s village character. Main Street is designated Limited Commercial to serve community needs, and the plan discourages strip commercial development along Old Redwood Highway. Practical effects for a buyer:

• Design review. New commercial buildings, expansions and remodels require architectural and site design review, using design standards in the plan’s appendix. Those standards ask for matching building heights and colors, screened parking, equal treatment of a corner building’s street sides, and signs made of painted or applied letters that do not project from walls or roofs.
• Undergrounding. New commercial structures must underground utilities before final occupancy.
• Historic district. The plan recommends Historic District designation for central Penngrove. Check whether a Historic combining district now applies to the parcel, because it adds review for exterior changes.
• Upper-floor apartments. Because apartments are a secondary use in Limited Commercial, a mixed-use building with homes above shops can fit Main Street, subject to the zoning code and parking.
• Street improvements. The plan calls for grants for Main Street landscaping, parking, sidewalks and undergrounding, and bus stops near the post office and at Adobe Road.

Rural business, scenic corridors and community separators

Outside the village, Penngrove’s land is mostly Diverse Agriculture and rural residential. Agricultural businesses, including farm stays, tasting or event uses where the county’s agricultural zoning allows them, depend on the parcel’s base zone, Williamson Act status and septic and well capacity.

• Scenic corridors. Adobe Road and Petaluma Hill Road are designated scenic corridors, which affects setbacks, signs and building siting.
• Community separator. The land south of Ely Road is a community separator forming the edge of Petaluma, the open plain between Ely and Adobe Roads is designated community form land, and the area north of Adobe Road is a scenic landscape unit. Subdivisions there need a visual analysis, with building envelopes kept below ridgelines.
• Traffic. The plan expects Old Redwood Highway to be widened to four lanes and asks development there to limit direct driveways and use Goodwin Avenue for access.

Sewer, water and septic

• Sewer. The Penngrove Sanitation Zone, run by Sonoma Water, covers about 475 acres and is a collection system only. Its sewage flows through a lift station into Petaluma’s system for treatment, and Sonoma Water has studied the zone’s peak wet-weather capacity against the state’s 2022 requirements.
• Water. The plan identifies the Penngrove Water Company as the village’s water supplier and describes a building permit moratorium tied to a state water connection ban. That text dates from the plan’s adoption era, so ask the water company directly whether new or larger connections are available today.
• Septic. Outside sewer service, the plan requires percolation tests and creek setbacks and sets a 1.5-acre minimum lot size for parcels on septic and private wells, which limits how much business use a rural site can support.

Transfer tax, business tax and property tax

The Sonoma County Clerk-Recorder charges $0.55 per $500 of value, after deducting assumed loans; because Penngrove is unincorporated, the deed declaration should say "unincorporated," and the Petaluma city tax does not apply. A purchase is generally a change in ownership under Proposition 13, so budget reassessment to the price. We did not verify county business license requirements.

Due diligence that matters in Penngrove

Start with our commercial due diligence checklist, then add:

• Confirm the parcel is unincorporated and not inside Petaluma or Rohnert Park.
• Pull both the area plan designation and the county zoning district.
• Ask the Penngrove Water Company and Sonoma Water for written capacity before planning a more intensive use.
• On septic, confirm the system’s design flow and replacement area.
• Check for a Historic combining district in the village core and for scenic corridor rules on Adobe and Petaluma Hill Roads.
• Budget for design review and utility undergrounding on new commercial construction.

Questions people ask

Sources & notes

1. Penngrove Area Plan (Permit Sonoma)
2. Permit Sonoma, Area and Specific Plans
3. Sonoma Water, Penngrove Sanitation Zone
4. Sonoma County Clerk-Recorder, documentary transfer tax

Note: The Penngrove Area Plan is hosted in Permit Sonoma’s archive; some of its descriptions, including the water moratorium, may be out of date. We did not verify current zoning districts on Main Street, whether a Historic combining district has been applied, or the results of the sanitation zone capacity study. Descriptions of business locations are general.

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

Related: Penngrove real estate guide · Multifamily property in Penngrove · Commercial real estate services · Sonoma County commercial guide · Sonoma County multifamily guide