Forest Knolls, CA Real Estate & Homes for Sale
By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.
Forest Knolls is an unincorporated village in the San Geronimo Valley of Marin County, California, ZIP 94933, that the Census Bureau counts together with neighboring Lagunitas; the combined place has about 1,600 residents and 930 homes on 4.2 square miles. It’s a very thin market: Redfin recorded one sale, at $725,000, in the three months ending August 2026, so the Census estimate of $939,500 for owner-occupied homes is the better guide. Marin County handles permits and planning.
- County
- Marin County
- Government
- Unincorporated (Marin County rules)
- ZIP code
- 94933
- Census place
- Lagunitas-Forest Knolls, 1,626 residents (ACS 2020–2024)
- Median home value
- $939,500 (±$77,099, ACS 2020–2024)
- Short-term rental licenses
- 8 (cap does not step down)
- School district
- Lagunitas School District
Forest Knolls homes for sale
Listings for Forest Knolls and ZIP 94933 load below. Because a single sale can be the whole quarter here, add Lagunitas and San Geronimo to your saved property search.
What do homes in Forest Knolls sell for?
$939,500
Lagunitas-Forest Knolls, 2020–2024, Census ACS
1
3 months to August 2026, Redfin ($725,000)
$1,678,750
C.A.R., single-family, September 2026
Redfin’s ZIP 94933 page reported a $725,000 median, down 30.3% from a year earlier, but that “median” is a single sale, and the page’s 31.8%-over-list and 33-day figures describe the same house. It isn’t a trend. The Census figure pools five years of owner estimates for Forest Knolls and Lagunitas together; its margin, about $77,000, is the narrowest of the valley’s three Census estimates, which makes it the more useful anchor.
| Measure | Figure | Period and source |
|---|---|---|
| Homes sold, ZIP 94933 | 1, at $725,000 ($630 per sq ft) | Redfin, three months ending August 2026 |
| Owner-occupied home value (median) | $939,500 (±$77,099) | ACS 2020–2024 via Census Reporter |
| Housing units / occupied units | About 933 / 818 (each ±212) | Lagunitas-Forest Knolls, 2020–2024, Census ACS |
| Marin County median, single-family | $1,678,750 | September 2026, C.A.R. |
In practice, we price a Forest Knolls home from sales across the whole valley, adjusted for the things that vary most from lot to lot here: the septic system’s condition, the slope and the driveway, and how close the house sits to a creek.
Where is Forest Knolls, and what is “Lagunitas-Forest Knolls”?
Forest Knolls is one of the four villages of the San Geronimo Valley, in central Marin County, alongside Woodacre, San Geronimo and Lagunitas, the village the Census Bureau groups it with. It has no city government, so Marin County’s Community Development Agency handles building permits and planning, and the only transfer tax on a sale is the county’s $1.10 per $1,000.
The name dates from the valley’s subdivision after the early 1910s. The San Geronimo Valley Historical Society credits the Lagunitas Development Company, which bought valley land from the Mailliard heirs, with inventing both “Forest Knolls” and “Woodacre” as it subdivided; the area was mainly summer homes until after World War II. The Census Bureau doesn’t map Forest Knolls on its own. It reports figures for “Lagunitas-Forest Knolls,” which is why population counts for the village alone aren’t available.
The survey’s numbers hint at a mixed pattern of use. Of roughly 933 homes in the combined place, about 818 were someone’s usual residence, leaving around 115 vacant, seasonal or between occupants. That’s a larger share than the survey shows for Woodacre, although the margins on both are wide.
Septic, water and building limits on Forest Knolls parcels
Individual septic systems prevail in rural West Marin, as the Point Reyes Light has put it, and the county’s 2019 community-sewer study looked only at the Woodacre and San Geronimo Flats. Plan on a septic system and confirm how the house is served from the seller’s disclosures and the county file. Septic systems are permitted by Marin County Environmental Health Services, and four points matter most for a buyer.
- Bedrooms and design flow. A septic system is sized by bedroom count. The county’s design standard is 150 gallons per day per bedroom, and its rule rewrite, targeted for adoption by the end of 2026, is weighing a lower figure; 105 gallons is common with low-flow fixture credit (county septic update). If you plan to add a bedroom, the system’s capacity decides whether you can.
- The county file. Systems are classed I to IV, from code-complying to undocumented or failing. An inspection at sale is recommended, not required, so ask for the records and order one yourself.
- Water supply. Marin Water’s territory extends west to the San Geronimo Valley, according to Marin LAFCo. Confirm that the house is on the district’s system; a home on its own well needs a county operating permit.
- Creek buffers. Work inside a mapped Stream Conservation Area in the valley falls under the San Geronimo Valley stream rules the county adopted in July 2022 to protect coho and steelhead. Our San Geronimo page explains how they work.
On a Forest Knolls parcel, check septic capacity before you plan an addition or a second unit. A larger house can need a larger system, and on a sloped or creekside lot there may be no room to build one.
Wildfire and evacuation in Forest Knolls
When the Irving Fire started near the Mount Barnabe lookout in Lagunitas overnight on September 10, 2018, Forest Knolls was placed under an evacuation warning along with San Geronimo and lower Lagunitas, and evacuees were taken to the Lagunitas School and Community Center in San Geronimo. The fire burned more than 100 acres, and no homes were reported destroyed (Fire Safe Marin).
- Register for alerts: evacuation orders reach residents through Alert Marin, which needs a sign-up.
- Read the hazard map: find the parcel’s Fire Hazard Severity Zone on the State Fire Marshal’s viewer; the state-responsibility maps were updated effective April 1, 2024. High and Very High zones trigger AB 38 defensible-space paperwork at sale.
- Fire service: Marin County Fire is moving its headquarters from Woodacre to a new campus at San Geronimo Commons that the county says will support faster response times for the valley; construction is planned from fall 2027 (County of Marin).
- Paramedics: the San Geronimo Valley is one of the West Marin areas in County Service Area 28, which helps fund around-the-clock paramedic coverage.
Renting out a Forest Knolls home
Forest Knolls is the only valley village whose short-term rental cap doesn’t shrink over time: the county allots it eight licenses, initial and ultimate (Marin County CDA, February 2025). That doesn’t make a license easy to get. Licenses expire on any change of ownership, new applicants wait in a first-come queue, and accessory units created or legalized since 2020 generally can’t be licensed for stays under 30 days. For a long-term rental, the county’s just-cause ordinance covers only properties with three or more units, and increases above 5% in a year go to mandatory mediation. See our investor services before you buy for income.
Getting around from Forest Knolls
Most trips start on Sir Francis Drake Boulevard, which runs east toward Fairfax and San Rafael and west toward Olema. The Stagecoach bus, Marin Transit Route 68, covers the same corridor between the San Rafael Transit Center and Inverness, with eight westbound weekday trips on the April 2026 schedule (Marin Transit). For Lagunitas-Forest Knolls workers, the Census survey’s mean commute was about 32 minutes, with a wide margin.
Forest Knolls compared with nearby areas
| Area | Census geography | One verified difference |
|---|---|---|
| Forest Knolls | Part of Lagunitas-Forest Knolls | 8 short-term rental licenses, no step-down; 1 Redfin-recorded sale in the 3 months to August 2026 |
| Lagunitas | Part of Lagunitas-Forest Knolls | ZIP 94938; borders Samuel P. Taylor State Park; 6 licenses, falling to 4 |
| San Geronimo | Own Census place, 583 residents | Owner-estimated median $1,175,500, with a margin over $400,000 |
| Woodacre | Own Census place, 1,627 residents | Sewer study of up to about 360 Flats properties (2019) |
| San Anselmo | Incorporated town | Its own planning department; Golden Gate Transit Route 132 to San Francisco |
How Diamond Real Estate Group helps Forest Knolls buyers
With so few sales, a Forest Knolls price has to be argued from the property itself, and so does the decision to buy. We pull the septic history and match it to the bedroom count, ask the county about creek buffers before you plan any work, check the fire zone and AB 38 paperwork, and get insurance quotes moving early so you know the carrying cost.
For county-wide rules, see our Marin County real estate guide; for how a purchase runs with us, see our buyer services. Owners thinking about a sale can start with our selling services.
Selling a home in Forest Knolls
Forest Knolls is governed by Marin County, so permits, plans and septic records come from county departments rather than a town hall. The Community Development Agency’s online Public Access Viewer covers past building permits and planning approvals, and a parallel viewer covers Environmental Health’s septic and well files. Search by parcel number; on hillside streets, older permits are easier to match to the right house that way.
What buyers will ask about the lot
Many Forest Knolls homes combine a sloped lot with private systems, and buyers’ questions follow the site. Expect requests for:
- Septic records. No county inspection is required when the house sells. The county’s own advice to buyers is to get the records and, where nothing is on file, an evaluation by a septic inspector. A system with no permit record is graded Class IV, so find out before a buyer does.
- Bedroom count against design flow. County rules size a system at 150 gallons per day per bedroom, so a converted office or loft marketed as a bedroom invites a capacity question.
- Water. If the house uses its own well, show the county permit to operate it as a domestic supply; the county’s Code Chapter 7.28 sets minimum pumping volumes and water quality.
- Permits for decks, retaining walls and additions on the slope, matched to the county file.
Our article on well and septic inspections in Marin and Napa explains what an inspector reports.
Fire, transfer tax and forms
Check the parcel in Marin County Fire’s online lookup. A High or Very High hazard rating means the buyer gets documentation of a defensible-space inspection under AB 38, or the two sides agree that the buyer will obtain it within a year after escrow closes. Plan the clearance work before the inspection, not after.
Marin’s documentary transfer tax, $0.55 per $500, is the only one that applies in Forest Knolls. The seller customarily pays in Diamond’s North Bay markets, but the contract can split it differently; see our transfer tax guide. The state also requires a signed statement that the water heater is braced.
Because one sale can be a whole quarter’s data here, ask for a home valuation built from valley-wide comparables.
Sources for this section: County of Marin Community Development Agency: Records search (Public Access Viewer); County of Marin Environmental Health Services: Septic regulations update (LAMP); County of Marin Environmental Health Services: Septic systems program; County of Marin Environmental Health Services: Wells and water systems; Marin County Fire: What is an AB-38 inspection?; Marin County Assessor-Recorder: Fees (documentary transfer tax); California Public Law: Health and Safety Code 19211 (water heater bracing).
Forest Knolls real estate FAQs
Where is Forest Knolls, California?
In the San Geronimo Valley of central Marin County, next to Lagunitas, with which the Census Bureau groups it. It’s unincorporated, so county rules apply.
What is the ZIP code for Forest Knolls?
94933. Lagunitas, next door, has its own ZIP code, 94938.
Is Forest Knolls part of San Francisco?
No. The Forest Knolls in ZIP 94933 is an unincorporated village in Marin County, north of the Golden Gate. Check the ZIP code on any listing or data page, because records get mislabeled: Redfin’s ZIP 94933 page, for one, listed a recent sale under “San Francisco.”
What does “Lagunitas-Forest Knolls” mean?
It’s the Census Bureau’s name for the statistical area that combines the two villages, and it’s why there’s no official population count for Forest Knolls alone. The 2020–2024 survey counted 1,626 residents and about 933 homes there on 4.2 square miles.
How much do homes cost in Forest Knolls?
The Census estimate of owner-occupied home values for Lagunitas-Forest Knolls is $939,500. Redfin counted only one sale in ZIP 94933 in the three months ending August 2026, at $725,000, so recent sales across the valley are the better comparison.
Is there sewer service in Forest Knolls?
Plan on a septic system. The county’s 2019 community-sewer study covered only the Woodacre and San Geronimo Flats, and septic systems fall under Marin County Environmental Health rules, which the county is rewriting with adoption targeted for the end of 2026. Confirm how a specific house is served from the disclosures and the county’s records.
Can I add a bedroom to a Forest Knolls house?
Only if the septic system can take the added design flow, currently 150 gallons per day per bedroom under county standards, and if the work meets the valley’s stream rules where the lot is in a mapped Stream Conservation Area. Have the system evaluated before you design anything.
Was Forest Knolls evacuated in the 2018 Irving Fire?
It was under an evacuation warning, not an order; the orders covered specific streets closer to the fire. No homes were reported destroyed.
Can I rent my Forest Knolls home to visitors?
Only with one of the eight county short-term rental licenses for Forest Knolls. A license doesn’t transfer to a buyer, so a new owner applies and waits.
Which school district serves Forest Knolls?
The Lagunitas School District, which serves the unincorporated San Geronimo Valley from its K–8 campus in San Geronimo. Confirm the school for an address with the district.
Is there public transit from Forest Knolls?
Marin Transit’s Route 68, the Stagecoach, runs along Sir Francis Drake Boulevard to Fairfax and San Rafael and west to Point Reyes Station, about eight times each way on weekdays.
Sources & notes
- Redfin: ZIP 94933 housing market (August 2026), Census Reporter: Lagunitas-Forest Knolls, ACS 2020–2024 and C.A.R.: September 2026 sales report
- San Geronimo Valley Historical Society: valley history
- Marin County EHS: septic systems and septic regulations update (October 2026)
- Fire Safe Marin: Irving Fire (September 2018), State Fire Marshal: hazard zones and County of Marin: fire headquarters contract (July 7, 2026)
- Marin County CDA: short-term rental procedures (February 2025), mandatory mediation program and County Service Areas
- Marin LAFCo: Lagunitas School District and Marin Water, Marin Transit: Route 68 and Marin County Assessor-Recorder: transfer tax
Figures carry their dates where they appear, and we refresh market numbers every quarter. This is general information, not legal, tax or insurance advice; confirm the rules for a specific property with the agency named. Last reviewed October 2026 by Matthew Martinez.
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Local resource: Marin County planning and township resources. Check official information for the address you are considering; area descriptions do not establish a property’s permitted uses.
