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Tam Valley, CA: Tamalpais Valley and Homestead Valley Homes

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

Tamalpais Valley (Tam Valley) and neighboring Homestead Valley are unincorporated communities in southern Marin County, just outside the City of Mill Valley, with Mill Valley mailing addresses but county government. Marin County handles planning and building permits, local special districts collect sewage and run local services, the Southern Marin Fire Protection District provides fire service, and a sale pays only the county transfer tax. Before relying on any Mill Valley city rule, confirm which side of the city line a parcel sits on.

The Census Bureau groups the two valleys into the Tamalpais-Homestead Valley census-designated place, which counted 11,492 residents in 2020 on 4.69 square miles of land. Its 2020-2024 American Community Survey estimates put the owner-occupied share of homes at 85.4 percent and the median value of owner-occupied homes at $1,863,900. The county describes the Tam Junction, Manzanita and Shoreline areas, around the intersection of Shoreline Highway and Almonte Boulevard, as the business hub of Tamalpais Valley.

Tamalpais Valley homes for sale

Tamalpais Valley market report

Who governs Tam Valley and Homestead Valley

The most common mistake buyers make here is assuming that a Mill Valley address means City of Mill Valley rules. The table shows who handles what for most unincorporated parcels in the two valleys; confirm each one for the specific address.

Service or rule	Tamalpais Valley	Homestead Valley
Planning, zoning, building permits	County of Marin Community Development Agency	County of Marin Community Development Agency
Sewer collection	Tamalpais Community Services District	Homestead Valley Sanitary District
Sewage treatment	Sewerage Agency of Southern Marin (SASM)	SASM
Garbage service	Tamalpais Community Services District	Contract administered by the sanitary district
Fire and emergency service	Southern Marin Fire Protection District	Southern Marin Fire Protection District
Flood control	Marin County Flood Control Zone 3	Marin County Flood Control Zone 3
Transfer tax at sale	County only	County only

Almonte, the small unincorporated area just south of the Mill Valley city limits near Tam Junction, has its own Almonte Sanitary District, which Marin LAFCo describes as covering 0.4 square miles. Marin LAFCo describes the Marin Municipal Water District (Marin Water) as serving communities from the Golden Gate Bridge north to southern Novato and west to the San Geronimo Valley; confirm the parcel’s water provider from a recent bill or the title report. The Mill Valley School District’s schools include Tam Valley Elementary School, and the district can confirm attendance boundaries for an address. Check for any homeowners’ association in the preliminary title report, not a listing description.

The local districts and what they do

Tamalpais Community Services District

Marin LAFCo lists the Tamalpais Community Services District’s services as sewage collection and system maintenance, garbage collection including recycling, parks and recreation, community facilities and open space management. It serves the unincorporated Tamalpais Valley area, about 1.7 square miles and 7,500 people as of 2020. The district office is at 305 Bell Lane, and its board meets at the Tam Valley Community Center, 203 Marin Avenue. A five-member board elected to four-year terms governs it.

Homestead Valley Sanitary District

The Homestead Valley Sanitary District covers about 0.7 square miles of unincorporated Homestead Valley. According to Marin LAFCo, it handles sewage collection and system maintenance and administers a garbage collection contract. The district’s own site says it provides only collection, with treatment and disposal by SASM. Its board meets at the Homestead Valley Community Center, 315 Montford Avenue.

Sewerage Agency of Southern Marin

SASM is a joint powers agency formed in 1979 to handle wastewater collection, treatment, reclamation and disposal for southern Marin. Marin LAFCo lists its members as the City of Mill Valley, Almonte Sanitary District, Alto Sanitary District, Richardson’s Bay Sanitary District and the Tamalpais Valley district. It serves about 29,500 residents.

Sewer laterals and other requirements at sale

Inside the City of Mill Valley, Municipal Code section 17.04.270 requires the owner to give the City Engineer a sewer lateral inspection report before a sale transfers title, and the chapter applies to property situated within the city. The city also requires a residential building record report (see our Mill Valley guide). Those are city rules, and they don’t automatically follow a Mill Valley mailing address into the unincorporated valleys. We didn’t find a published point-of-sale lateral rule for the Tamalpais Community Services District or the Homestead Valley Sanitary District. Call the district that serves the parcel before listing, ask whether any lateral inspection, certificate or permit is required at transfer, and get the answer in writing.

Many buyers ask for a lateral video regardless, so consider ordering one before listing and ask the district which part of the line is the owner’s to maintain. Other statewide items still apply:

Fire zone documentation. Under Civil Code section 1102.19, a seller of residential property in a High or Very High Fire Hazard Severity Zone must give the buyer documentation of compliance with defensible space rules. Without it, buyer and seller can agree in writing that the buyer will obtain it, within one year of closing where no local ordinance applies.
Natural hazard disclosures. Flood, fire and other mapped hazards appear in the natural hazard disclosure report.
Transfer tax. The Marin County Assessor-Recorder charges $0.55 per $500 of value, or $1.10 per $1,000, and lists San Rafael as the only city with its own tax. Sellers customarily pay in Diamond’s North Bay markets, but it’s negotiable; see California transfer tax.

Our Marin County selling requirements by town lays out the city and district rules side by side.

Flood risk near Coyote Creek and Richardson Bay

The lower parts of Tam Valley drain to Richardson Bay through Coyote Creek. The county’s Flood Control Zone 3, formed in 1956 for creek and tidal flooding next to Richardson Bay, covers more than 13 square miles and 12,560 parcels, including the City of Mill Valley, Tamalpais Valley, Homestead Valley, Almonte, Alto and Marin City. Coyote Creek is one of its three subwatersheds. The zone maintains 1.3 miles of levees and 13 pumps at five pump stations, and periodically dredges sediment from the concrete channel of lower Coyote Creek.

Levee work is under way on the creek itself. The flood district circulated a draft initial study and mitigated negative declaration for the Cardinal Road Levee Upgrade Project, along Coyote Creek near Cardinal Road east of Flamingo Road, with public comment from October 31 to December 1, 2025. Buyers of nearby homes should ask the district where the project stands.

Low ground around Tam Junction is where flooding shows up first. In a July 27, 2026 release, the County Community Development Agency said waterfront areas on the west side of Richardson Bay are often flooded by winter storm surges, king tides and long-term sea level rise, and that Shoreline Highway and adjacent roads can sometimes be impassable. Uphill homes in the valleys face a different set of risks: slope, drainage and fire.

For any parcel, look up the FEMA flood zone, ask for an elevation certificate and flood insurance history if the home is on low ground, and read our guide to flood zones in the North Bay.

Wildfire and fire service

The Southern Marin Fire Protection District serves Tamalpais Valley, Almonte, Homestead Valley, Alto, Strawberry, Sausalito, Mill Valley, Fort Baker, the Marin Headlands and about a quarter of Tiburon, covering more than 25.3 square miles. It was formed in 1999 by merging the Alto-Richardson and Tamalpais fire protection districts, annexed Sausalito’s fire department in 2012 and annexed the City of Mill Valley on July 1, 2023. The district places Tam and Homestead Valley in one of its five protection zones.

Fire hazard severity zones are mapped parcel by parcel, and the zone decides the defensible-space paperwork at sale and affects insurance. Hillside lots near open space deserve the closest look. Check the parcel on the state’s map and see our guide to fire hazard severity zones in the North Bay; get insurance quotes as soon as you’re in contract.

Building, remodeling and short-term rentals

Additions, remodels, ADUs and site work go through the County of Marin, not Mill Valley’s planning department. The county’s Tamalpais Area Community Plan, whose draft environmental impact report was filed with the state in 1991, sets local goals and policies for the area, so ask county planning which plan policies and design review apply to a project before you buy. Our guide to Marin renovation and design review explains the process.

Planning is also looking at Tam Junction itself. The county’s Tam Junction Placemaking Study covers the Tam Junction, Manzanita and Shoreline areas and is aimed at safety, access and circulation; the county said the work plan would go to the Board of Supervisors in late fall 2026 and the study would launch in early 2027.

Short-term rentals in unincorporated Marin need a county license. The county’s October 2026 administrative procedures cap licenses at 1,200 countywide (excluding Dillon Beach) and keep waitlists when applications exceed available licenses. If rental income is part of your plan, read our guide to short-term rental rules in Marin County, including what happens to a license when a property is sold.

Getting around

Shoreline Highway (State Route 1) runs through Tam Junction and connects the valleys to Highway 101. Marin Transit’s Route 61 runs from Sausalito through the Marin City hub and Tam Junction (Shoreline Highway and Almonte Boulevard), then over Panoramic Highway toward Stinson Beach and Bolinas, with weekday and weekend schedules. Eastbound trips also stop at the Manzanita Park and Ride lot. Neighboring Sausalito has ferry service to San Francisco, and Muir Beach sits farther west on Highway 1.

Tam Valley compared with the City of Mill Valley

Question	Tam Valley and Homestead Valley	City of Mill Valley
Government	Unincorporated Marin County	Incorporated city
Permits	County Community Development Agency	City planning and building
Sewer at sale	Ask the local district; no published rule found	City lateral inspection report required
Records report at sale	None found at the county level	City residential building record report
Short-term rentals	County license, capped countywide	City registration rules
Transfer tax	County only	County only
Fire service	Southern Marin Fire	Southern Marin Fire (since July 2023)

For the city side in detail, see the Mill Valley guide linked above, and for the rest of the county, our Marin County guide.

Selling a home in Tam Valley or Homestead Valley

Sellers here gain the most by settling jurisdiction questions before buyers ask them. Before listing, gather:

The parcel’s jurisdiction and districts, confirmed from the title report: county, sanitary district or Tamalpais CSD, and fire district.
The sewer district’s written answer on any requirement at transfer, plus a recent lateral video if you have one.
County permits for additions, decks, retaining walls and any second unit.
Defensible-space documentation if the parcel is in a High or Very High fire zone.
Flood insurance history and any elevation certificate for low-lying homes near Coyote Creek or Tam Junction.
The county short-term rental license, if the home has been rented short term.

Price against true comparables: a valley-floor house near Tam Junction, a hillside home with long views and a lot near open space can draw different buyers and carry different insurance costs. Our home valuation is the place to start.

Questions people ask

Is Tam Valley part of Mill Valley?

No. Tamalpais Valley is unincorporated Marin County, even though homes have Mill Valley mailing addresses. The county handles permits and planning, and the Tamalpais Community Services District provides sewer collection, garbage service and parks.

Is Homestead Valley the same as Tam Valley?

No. They’re neighboring unincorporated valleys with separate sewer agencies: the Tamalpais Community Services District in Tam Valley and the Homestead Valley Sanitary District in Homestead Valley. The Census Bureau combines them into the Tamalpais-Homestead Valley census-designated place.

Do I need a sewer lateral inspection to sell in Tam Valley?

Mill Valley’s city requirement doesn’t apply to unincorporated parcels, and we found no published point-of-sale rule for the Tam Valley or Homestead Valley districts. Ask the district serving the parcel in writing before you list, and expect buyers to ask for a lateral video.

Who provides fire service in Tamalpais Valley?

The Southern Marin Fire Protection District, which also serves Homestead Valley, Almonte, Alto, Strawberry, Sausalito, Mill Valley and part of Tiburon.

Does Tam Valley flood?

Low-lying areas near Tam Junction and Coyote Creek can. The county says Shoreline Highway and nearby roads are sometimes impassable during storm surges and king tides. Flood Control Zone 3 maintains levees and pump stations and dredges lower Coyote Creek.

Is there a city transfer tax in Tam Valley?

No. Only Marin County’s documentary transfer tax of $1.10 per $1,000 applies. The county recorder lists San Rafael as the only Marin city with its own transfer tax.

Can I rent my Tam Valley home short term?

Only with a county short-term rental license. Licenses are capped at 1,200 across unincorporated Marin, with waitlists when demand exceeds supply, so check availability before buying with rental income in mind.

This is general information, not legal advice. District rules at sale, permit history and hazard zones are specific to each parcel, so confirm them with the County of Marin and the local district, and ask a California real estate attorney about anything unusual on title.

If you’re buying or selling in Tam Valley or Homestead Valley, contact Diamond Real Estate Group and we’ll help you sort out the county and district rules before you commit.

Sources & notes

Last reviewed October 2026 by Matthew Martinez.