In Belmont's Hills, the Right to Build Can Be Worth More Than the Lot

A Belmont hillside lot can carry an assessor's parcel number, a listing price, and a view over San Juan Canyon, and still not be a legal building site. Every year, the city's own planning department hears from buyers who find this out after closing escrow, when the land they bought to build a house on turns out to need a road that doesn't exist yet, a geotechnical study nobody has commissioned, or a floor area allowance so small the design barely qualifies as a home.

Understanding why takes about five minutes, and it changes how you read a listing in San Juan Hills or the Western Hills before you write an offer, not after.

Zoned Residential Doesn't Mean Cleared to Build

Most Belmont hillside parcels carry a residential zoning designation, and that's where a lot of buyers stop reading. But, as Belmont's hillside-development FAQ explains, San Juan Hills and Western Hills sit inside the city's Hillside Residential and Open Space districts, known as HRO-1 and HRO-2, and that classification exists specifically because the terrain underneath a residential zoning stamp comes with its own hazards: steep grades, soil instability, and roads that were never fully built out to city standard. The zoning tells you what a lot could become. It doesn't tell you whether the site can clear the additional review that hillside land in Belmont requires before a permit gets issued.

That additional review runs on three separate tracks, and any one of them can stall a project for years.

Three Approvals Standing Between a Parcel Number and a Permit

• Certificate of Compliance review. Many hillside parcels were created through subdivisions that predate current state and city standards. Before a permit application moves forward, the City of Belmont's hillside-development guidance says the city has to confirm the parcel itself was legally created, and that review process is its own gate, separate from anything about the house you want to build.
• A geotechnical study. Any site with potential slope stability problems needs a professional report before the city will evaluate a design, as Smart Preservation explains; the city then peer reviews that report on its own dime and timeline.
• A road or access improvement plan. If a lot's frontage doesn't meet the city's Hillside Road Standards, or if there's no roadway there at all, that roadway has to be designed, reviewed, and approved before anyone can build on the parcels it's meant to serve.

A lot can pass on one of these tracks and stall on another. That's the pattern behind the city's own warning to buyers: land advertised as developable can turn out to need permitting that takes years and money most buyers didn't budget for.

The Formula That Shrinks Your Buildable Square Footage as the Slope Rises

Even once a hillside parcel clears those approvals, the amount you're allowed to build shrinks as the ground gets steeper. In the HRO-2 zone, which covers land that's already subdivided, any lot of 40,000 square feet or larger is capped at 3,500 square feet of floor area, full stop. Smaller lots start with an allowance of up to 1,200 square feet if the average slope is 10 percent or less, but that number drops as the slope increases, down to just 900 square feet on a lot at a 45-degree grade or steeper. The city built the formula this way on purpose, to keep the size of what gets built proportional to how much grading and terrain disruption it takes to build it.

That's a different calculation from the one that governs how many new lots can be carved out of raw, undivided hillside land in the first place. Where San Juan Hills still has unsubdivided parcels, the area plan, as described in the Belmont City Council meeting record, sets density based on average slope too, but measured in dwelling units per net acre rather than square footage, ranging from 0.3 to 4.4 units per acre. When the city reviewed its own Bishop Road property for subdivision, the parcel's 24 percent average slope worked out to a ceiling of 0.508 units per acre. The project that went through came in at 0.488, just under that ceiling. Even the city, acting as its own applicant, had to run the same math a private buyer would.

Why Some Owners Sell the Building Right Instead of the House

This is exactly why Belmont built a market for development rights inside HRO-2. An owner whose lot is too steep to build on efficiently, or who doesn't want to fund a geotechnical study for a site that might not clear it anyway, can transfer the right to build somewhere else in the zone instead of building on their own dirt. The amount that transfers is whichever is larger: 1,200 square feet, or whatever floor area the sending lot could have supported on its own. A receiving site can add that square footage to its own allowance, though no property, transfer or no transfer, can ever exceed the 3,500 square foot ceiling.

Until 2018, a transfer had to stay on the same roadway and within the same subarea of the San Juan Hills plan. A code amendment that year opened transfers to any property anywhere in the HRO-2 zone. San Juan Hills has three named plateau neighborhoods, Skymont, Plateau, and Cipriani, sitting between stretches of undeveloped, unimproved land where drainage, water, and sewer service were never extended. A development right sitting on an inaccessible parcel near Cipriani can now, in principle, add square footage to a house going up on Skymont.

That's the part that should change how you read a "for sale" sign on a steep, roadless parcel in Belmont. The land itself might never support a house. The right attached to it can still be worth something to someone else's project.

Two Belmont Parcels That Show How Long This Can Take

The city's own history with this land makes the timeline concrete. In December 2009, the Belmont City Council authorized buying 87 vacant parcels, about 35 acres, at a U.S. Marshal's Service auction, picking up the land along with back taxes and interest for roughly $1.5 million total. The goal was never a large subdivision. It was to preserve most of the acreage as public open space and sell a small portion to cover the acquisition cost. That portion, an 8 acre remainder, eventually sold for $2.05 million, with 6 of the 8 acres dedicated back to the city as permanent open space and the rest going through the same slope and density review any private buyer's project would face.

A private applicant has been working through the same kind of process on Monte Cresta Drive. The project there would add 335 feet of new roadway from the current end of Monte Cresta Drive at Sequoia Way, opening legal access to five parcels that have sat undeveloped for lack of a road. The Planning Commission held its hearing in May 2024, took extensive public testimony, and continued the item rather than voting to approve it, the last public milestone on record for the project. The lots weren't stalled because nobody wanted to build there. They were stalled because the access itself had to be designed, reviewed, and approved before anyone could pull a permit for a house, a step that had already carried the project past one Planning Commission cycle without a final vote.

What to Ask Before You Write an Offer on a Belmont Hillside Lot

1. Ask the city directly for the Certificate of Compliance status on the parcel. Don't rely on an old subdivision map or a seller's assurance.
2. Commission or request a geotechnical study before you commit to a design. Construction lenders will ask for one anyway.
3. Confirm the average slope calculation for the specific lot. It sets your floor area ceiling directly, and it isn't negotiable once measured.
4. Find out whether the parcel has legal road access today, or whether it depends on a plan like Monte Cresta Drive's that hasn't cleared the Planning Commission yet.
5. If the site is marginal, ask whether the seller has already looked into a development rights transfer. A parcel priced as vacant land may really be a transferable right, and the math on that is different from the math on a home site.

A Few Short Questions

Are Western Hills lots subject to the same review as San Juan Hills? Yes. The city treats both areas as a matched pair on its own hillside development guidance, subject to the same constraints and the same buyer warning, though the specific inventory of undeveloped lots and road access issues differs by area.

Can a development right transfer outside the HRO-2 zone? No. Since the 2018 amendment, transfers can happen between any two properties inside HRO-2, but the ordinance doesn't extend rights beyond that zone.

What's the largest home allowed in HRO-2, no matter how many rights transfer in? 3,500 square feet. That's the ordinance's ceiling regardless of transfers or original lot size.

If you're weighing a hillside lot in San Juan Hills or the Western Hills, run the zoning and access questions before you run the numbers on a build. LeDoux Group has sat with buyers through Belmont's Certificate of Compliance and geotechnical process on parcels like these, and we're glad to look at a specific lot with you before you write an offer.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.