At a Belmont Planning Commission public forum in October 2025, a resident named Max Reinhardt stood up to talk about his lot on Alhambra Drive. He wasn't raising a design objection or a neighbor dispute over a fence line. He was pointing out a discrepancy between how the San Juan Hills Area Plan classifies his parcel under HRO-2 zoning and how the city's own R-1 designation treats it, and asking, again, whether his Certificate of Compliance was ever resolved. He had raised nearly the same concern years earlier, in a 2021 Planning Commission session, on the same address. Another speaker that same October evening, a prospective builder named Arvind, said he'd emailed the city two weeks prior asking what his next steps were and hadn't heard back. The Community Development director, DeMello, acknowledged the backlog on the record and said staff was fielding a number of similar inquiries from San Juan Hills property owners.
None of this involves soil samples or seismic maps. It's paperwork, and in Belmont's hillside neighborhoods, the paperwork can outlast the geology.
A lot that looks buildable on paper isn't automatically a legal lot
Most homebuyers assume that if a parcel has an address, a listing, and a zoning designation, it can be built on. In San Juan Hills and Western Hills, that assumption fails often enough that the city built an entire process around it. Belmont's Community Development Department states directly that every year the city encounters buyers who purchase land expecting to build, only to discover the parcel is undevelopable or tangled in permitting that will run long past what they budgeted for.
The mechanism is called a Certificate of Compliance, and it exists because California's Subdivision Map Act requires proof that a parcel was legally created. Many lots in San Juan Hills and Western Hills date back to subdivisions platted decades before the current zoning code existed. If the paper trail proving legal creation is missing or incomplete, the city won't recognize the parcel as a separate legal lot for development purposes, regardless of what the tax assessor's map or the MLS listing implies. A conditional Certificate of Compliance can establish that legal record retroactively, but it comes loaded with conditions, and those conditions are typically calibrated to whatever standards would have applied had the lot gone through subdivision review properly, tied to when the current owner acquired their interest in the property. That last detail matters for a buyer: the rules that attach to your lot may depend on a purchase date that already happened, not the date you close.
Getting a Certificate of Compliance requires a formal written application to the Planning Department, a plot plan, supporting documentation, and a review fee set by City Council schedule. The city's subdivision ordinance spells out that the Director of Planning reviews the request and either issues the certificate or, if conditions need to be met first, issues a conditional certificate that gets filed with the County Recorder under state Government Code.
Where this is concentrated, and why
San Juan Hills sits in Belmont's northwestern hills, developed across three distinct plateaus known as Skymont, Plateau, and Cipriani. The undeveloped lots sit between those plateaus, often along unimproved roads or what planning documents call paper streets, meaning drainage, water, and sewer infrastructure was never extended to them. Ownership across these parcels is highly fragmented, which the city's own area plan flags as an obstacle to coherent development and a reason the plan actively encourages recombining lots rather than building on them individually. Slopes on the remaining vacant parcels run from 15 percent to 75 percent, and many carry documented geologic hazards on top of the legal-lot question.
Western Hills carries a parallel set of constraints under its own 1990 area plan, with the same Hillside Residential and Open Space overlay controlling what can be built once a lot clears the legal hurdle.
Clearing the Certificate of Compliance doesn't get you a normal house
Assume the paperwork resolves in your favor. The zoning that governs most of these hillside parcels, the HRO-2 district, caps floor area based on lot size and slope, not on what a comparable flatland lot in Belmont would allow.
| Lot condition | Maximum floor area |
|---|---|
| Lot 40,000 sq ft or larger | 3,500 sq ft |
| Lot under 40,000 sq ft, average slope 10% or less | up to 1,200 sq ft |
| Lot at 45 degrees of slope or steeper | as low as 900 sq ft |
The floor area figure includes everything under the roof, garage included. A 1,200 square foot allowance with a 400 square foot two-car garage leaves 800 square feet of actual living space, on a lot that may have taken years and a legal filing just to qualify as buildable at all.
Belmont anticipated that this math would discourage building on the steepest, most fragile lots, and built a release valve into the code. The city's Transfer of Development Rights program, adopted in 1988, lets an owner move floor area entitlement off a constrained sending site onto a receiving site instead of building on the original lot. The transferable amount is the greater of 1,200 square feet or whatever the sending lot could actually support, and the receiving site has to be in the HRO-2 zone as well. A 2018 code amendment loosened the original rule requiring sender and receiver to sit on the same roadway and statistical subarea, opening transfers to any HRO-2 property in the city.
The program has been used sparingly. Between 1988 and 1995, the city approved eleven transfers total, and ten of those eleven came from a single development where the original subdivision's road had been drawn across a landslide area. Rather than build on those lots, the city preserved them by deed restriction and shifted the floor area to homes elsewhere on the same street. For an owner sitting on a steep, legally clouded parcel, the honest financial question isn't always how to get a house approved on it. Sometimes it's whether that floor area is worth more moved to someone else's buildable lot.
What the timeline actually looks like
A single case file from Monte Cresta Drive shows how long this can run. The lot traces back to the 1927 Belmont Country Club Properties Subdivision, with just six feet of frontage on the paved portion of the cul-de-sac and the rest of its road frontage along an unimproved stretch, on a 27 percent upslope. The owner filed for a Hillside Roadway Improvement Plan in October 2000 to extend the pavement about 100 feet. A Lot Line Adjustment to merge three lots into one followed two months later and recorded in March 2001. The city reaffirmed the merger in December 2001. Then, according to Planning Commission records, various iterations of the roadway plan went through public hearings from 2002 through 2012. By 2015, the applicant was requesting a time extension on a Single-Family Design Review approval, with entitlements set to expire in September 2016 unless a building permit had already issued, and staff noted the project still had to clear Belmont's winter grading moratorium, which pauses hillside grading work until spring.
That is roughly fifteen years between the first roadway filing and a building permit still not in hand. A separate 2021 proposal at 800 Laurel Avenue, for 16 townhomes near the western terminus of Hill Street, needed its own stack of entitlements including rezoning, a conceptual development plan, a conditional use permit, a grading plan, and a vesting tentative map, with neighborhood concerns raised over wall heights, grading, and view impacts before anything broke ground.
The contrast that matters for a 2026 buyer
Belmont's overall housing market moves fast. Over the three months ending May 2026, homes sold at a median of roughly $2.2 million, went pending in around 12 days on average, and drew about 6 competing offers. That pace has nothing to do with what happens to a vacant hillside parcel once escrow closes. A flatland listing in Belmont can be under contract before the open house signs come down. A San Juan Hills lot can sit in Certificate of Compliance limbo for years after the deed transfers, with the buyer holding the carrying costs the entire time.
Before writing an offer on vacant or underbuilt hillside land in Belmont, it's worth asking the seller or listing agent directly whether a Certificate of Compliance has already been issued and recorded, and if not, whether one has even been applied for. The city's Community Development Department can confirm whether a parcel sits in the HRO-1, HRO-2, or HRO-3 overlay, since each carries different floor area math. Worth checking too is whether the parcel's road frontage is improved or falls along one of the area's paper streets, since roadway and access obligations under the San Juan Hills and Western Hills Area Plans can add both cost and time before any building permit issues. A geotechnical evaluation, typically running from roughly $2,000 to $10,000 or more depending on site complexity, answers the soil question, but it doesn't answer the legal-lot question, and buyers sometimes conflate the two.
A few questions worth asking before you make an offer
Does every hillside lot in San Juan Hills or Western Hills need a Certificate of Compliance? Not every one, but many parcels in these areas lack a clean recorded subdivision history, which is exactly why the city built a formal review process around it. Belmont's Community Development Department can confirm a specific parcel's status before you write an offer.
If a lot can't support a normal-sized house, is it still worth buying? It depends on whether the parcel is a workable receiving site for a floor area transfer from a neighboring constrained lot, or a strong sending site itself. Belmont's Transfer of Development Rights program has moved entitlement between properties before, though the city has approved relatively few transfers since the program began.
How long does a Certificate of Compliance review typically take? The city doesn't publish a fixed timeline, and case files show it can range from a routine review to a multi-year process, particularly when roadway improvements or a lot merger are involved.
Belmont's hills are a big part of why the city draws sustained demand, but the lots that carry the best views are sometimes the ones with the most complicated paper trail behind them. If you're weighing a hillside parcel or an older hillside property with expansion plans, Real Smart Group can help you pull the zoning overlay, check Certificate of Compliance status with the city, and get a realistic read on what the lot will actually support before you're locked into an offer.
