Complete Guide to Building a Custom Home in Hillsborough

Why Build a Custom Home in Hillsborough?

Hillsborough is one of the most distinctive residential communities in California. Located in San Mateo County between Burlingame, San Mateo, and the Crystal Springs Reservoir, the town of roughly 11,000 residents has no commercial zoning at all. There are no stores, no restaurants, no offices. The entire town is dedicated to residential living on large, landscaped lots along curving, tree-lined roads without sidewalks.

This is not an accident. Hillsborough was incorporated in 1910 specifically to preserve its residential character, and more than a century later, the town remains committed to that vision. The absence of commercial activity, combined with large lots, mature landscaping, and winding roads, creates an atmosphere that feels more like a private estate community than a Bay Area suburb.

For homeowners building a custom home, Hillsborough offers the Peninsula’s most private residential setting with direct access to San Francisco (20 minutes), SFO airport (10 minutes), and the broader Bay Area tech corridor. The town’s Architecture and Design Review Board ensures that new construction maintains the quality and character that residents expect.

For a step-by-step overview of the full building process, see our custom home building process guide.

Town Character and Real Estate Market

Hillsborough’s real estate market is among the most expensive on the Peninsula. Median home values exceed $5 million, and premium estates regularly sell for $10 million to $30 million+. The market is driven by the combination of location (central Peninsula with easy access to San Francisco, the airport, and Silicon Valley), character (entirely residential, private, estate-like), and school quality (the Hillsborough City School District is highly rated).

Most custom home projects in Hillsborough are teardown-rebuilds. The town has a significant inventory of homes built in the 1930s through 1970s that sit on excellent lots but no longer meet modern living standards. Purchasing one of these properties and building new is the primary path to a custom home.

Teardown candidates range from $4 million to $10 million+, with the land value comprising the majority of the purchase price. Vacant lots are extremely rare and command strong premiums when available.

The buyer profile includes tech executives, finance professionals, and established families who want Peninsula living without the density and commercial activity of neighboring cities like Burlingame and San Mateo.

Zoning and Development Standards

Residential-Only Zoning

Hillsborough’s zoning is exclusively residential. The town has multiple residential zones with different minimum lot sizes, setbacks, and coverage limits, but every zone is residential. This uniformity is the foundation of the town’s character and its strongest selling point.

Lot Size Requirements

Minimum lot sizes vary by zone:

• Some zones require a minimum of half an acre (approximately 21,780 square feet)
• Other zones require one acre or more
• Many existing properties exceed the minimum, with estate parcels of 2 to 5+ acres

Contact the Town of Hillsborough Building and Planning Department to confirm the specific zoning and development standards for your parcel.

Setbacks and Coverage

Setback requirements vary by zone but are generally generous. Front setbacks of 25 to 50 feet, side setbacks of 10 to 25 feet, and rear setbacks of 25 to 40 feet are common. Maximum lot coverage is limited to ensure that homes maintain significant open space, landscaping, and tree canopy.

Floor Area

Hillsborough regulates maximum floor area based on lot size. The formula is designed to ensure that homes remain proportional to their lots. Even on a one-acre parcel, you cannot build without limits. The floor area calculation includes the main home, garage, and any accessory structures.

Height Limits

Building height is limited to approximately 30 to 36 feet depending on the zone and roof type. On sloped lots, height is measured from natural grade, which can significantly restrict the building envelope on hillside properties.

The Architecture and Design Review Board

The Architecture and Design Review Board (ADRB) is Hillsborough’s primary mechanism for maintaining architectural quality and neighborhood character. Understanding this process is essential for any custom home project.

What Triggers ADRB Review

All new construction requires ADRB review. Significant remodels, additions, and exterior modifications also go through the board. Even projects that comply with all zoning standards must receive ADRB approval before a building permit is issued.

How the Process Works

The ADRB meets on a regular schedule (typically twice monthly). Applicants submit design documentation including site plans, floor plans, elevations, material samples, color boards, and landscape plans. The architect or project representative presents the design at a meeting, and the board provides feedback.

What the ADRB Evaluates

• Neighborhood compatibility. Does the design respect the scale, character, and architectural quality of surrounding homes?
• Massing and scale. Is the home proportional to the lot? Does it avoid the appearance of bulk or dominance?
• Materials and quality. Does the exterior material palette reflect the quality expected in Hillsborough?
• Privacy. Do windows, balconies, and outdoor spaces respect neighboring properties?
• Landscaping. Does the landscape plan integrate the home with the existing tree canopy and natural setting?
• Driveway and site work. Are the driveway, motor court, and site grading handled with appropriate quality and restraint?

Timeline and Expectations

New custom home projects typically require 2 to 4 ADRB meetings before receiving final approval. The first meeting is often a “preliminary review” where the board provides general feedback and direction. Subsequent meetings address revisions and refinements. Straightforward projects on flat lots with well-designed plans may move through faster. Complex hillside projects or designs that receive significant board feedback may require additional sessions.

Plan for 2 to 5 months for the ADRB process. This timeline runs before or concurrent with building permit plan check.

Building Permits and Timeline

Once ADRB approval is secured, the building permit process follows standard San Mateo County building code review.

Permit Plan Check

Building permit plan check in Hillsborough typically takes 6 to 12 weeks for new construction. The town’s Building Department reviews plans for structural compliance, energy code (Title 24), plumbing, electrical, and mechanical systems.

Total Project Timeline

The full timeline from design kickoff to move-in for a Hillsborough custom home is 18 to 30 months:

• Design and engineering: 3 to 5 months
• ADRB review: 2 to 5 months
• Permit plan check: 2 to 3 months
• Construction: 12 to 18 months

There is overlap between these phases. ADRB review can begin while engineering is being finalized, and building permit submission often follows shortly after ADRB approval.

Cost Expectations

All pricing is approximate, reflects 2026 Bay Area market conditions, and is subject to change. Every project is unique. Final costs are determined on a project-by-project basis during our design phase.

Custom home construction in Hillsborough costs $500 to $1,000+ per square foot in 2026, placing it among the most expensive residential construction markets in the Bay Area.

What Drives Costs

• Premium finish expectations. Hillsborough is a luxury market. New construction must compete with restored estates and recent custom builds that feature imported stone, custom millwork, designer fixtures, and whole-home automation.
• ADRB material standards. The Architecture and Design Review Board expects high-quality exterior materials. Budget construction materials will not pass review.
• Large home sizes. Custom homes in Hillsborough typically range from 4,000 to 8,000+ square feet, with estate projects exceeding 10,000 sqft.
• Estate-scale site work. Long driveways, motor courts, extensive landscaping, outdoor living areas, pools, and guest houses add to the scope.
• Hillside conditions. Properties on sloped terrain require engineered foundations, retaining walls, and specialized drainage, adding 15 to 30% to base costs.
• Peninsula labor market. Hillsborough draws from the same pool of skilled tradespeople as Atherton, Woodside, and the broader Peninsula, keeping labor costs elevated.

Budget Framework

For a 6,000 sqft custom home:

• Land: $5M to $12M+
• Construction: $3M to $6M+
• Architecture, engineering, permits: $200K to $500K
• Landscaping and outdoor living: $150K to $500K
• Contingency (10%): $300K to $600K

For a broader cost comparison, see our Bay Area custom home cost guide.

Key Areas and Neighborhoods

Hillsborough does not have formal neighborhood names in the way that larger cities do, but distinct areas have different characters and price points.

Lower Hillsborough / Burlingame Border

The most accessible area, bordering Burlingame along El Camino Real and the flatter eastern sections of town. Properties here tend to have smaller lots (by Hillsborough standards), easier terrain, and shorter driveways. Proximity to Burlingame’s downtown Broadway district adds convenience.

Central Hillsborough

The heart of the town, along roads like Marlborough Road, Remillard Drive, and Crystal Springs Road. A mix of older estates and newer custom homes. Rolling terrain with mature oak and eucalyptus trees. This area offers the quintessential Hillsborough experience: winding roads, no sidewalks, and homes set well back from the street behind landscaped grounds.

Upper Hillsborough / Crystal Springs Area

Higher-elevation properties near the Crystal Springs Reservoir and the western ridge. Larger lots, more dramatic terrain, and expansive views to the Bay and beyond. Construction is more complex due to hillside conditions, but the setting is spectacular.

Western Hills / Hayne Road Area

Premium estate properties with large acreage, significant privacy, and views. This area includes some of Hillsborough’s most impressive homes and attracts buyers who want maximum privacy and space within the town limits.

Architectural Styles

Hillsborough has a rich architectural history, with homes ranging from early 20th-century Tudor and Colonial Revival estates to mid-century modern and contemporary designs. The ADRB does not mandate a specific style but evaluates quality and neighborhood compatibility.

Traditional estate. Tudor, Georgian, Colonial Revival, and French Country styles have deep roots in Hillsborough. New construction in these styles connects to the town’s historic character and tends to move through ADRB review smoothly.

Mediterranean. Stucco, tile roofs, courtyards, and arched details. A strong presence in Hillsborough, particularly in the central and lower areas where the terrain is more moderate.

Contemporary. Clean lines, large windows, and modern materials. Increasingly accepted by the ADRB, particularly when the design demonstrates quality and thoughtful integration with the site. Contemporary homes on hillside lots where expansive glazing captures views are becoming more common.

Transitional. A blend of traditional proportions with modern interiors and finishes. This style often works well in established neighborhoods where a fully contemporary facade might feel out of context but homeowners want an open, modern interior.

Schools and Community

Hillsborough’s schools are a primary draw for families. The Hillsborough City School District (K-8) operates several highly rated schools, including North Hillsborough School, South Hillsborough School, West Hillsborough School, and Crocker Middle School. Students go on to attend high school in the San Mateo Union High School District, with many attending San Mateo High School or Burlingame High School.

The community values privacy and quiet living. Social life centers on school events, country club memberships (Burlingame Country Club and Crystal Springs Golf Club are nearby), and neighborhood connections rather than commercial entertainment.

Why Build with Custom Home Design and Build

Hillsborough’s ADRB process demands polished design presentations, high-quality material selections, and thorough documentation. Our team brings the design expertise and review board experience that this process requires.

Custom Home Design and Build’s two-phase approach aligns perfectly with Hillsborough’s regulatory framework. In Phase 1, we complete all design, ADRB presentations, engineering, and permitting. You approve every detail and receive locked-in pricing before construction begins. In Phase 2, we build to the standard this community expects.

If you are considering building a custom home in Hillsborough, we would welcome the opportunity to assess your property, discuss the ADRB process, and show you what is possible.

Contact us to start the conversation.