ADU Requirements in Burlingame: Zoning, Setbacks, and Permit Rules for 2026

Why Burlingame Homeowners Are Building ADUs

Burlingame sits in one of the most desirable corridors on the San Francisco Peninsula. Known as “the City of Trees” for its canopied residential streets and mature landscaping, the city blends small-town charm with direct access to San Francisco, Silicon Valley, and SFO. It is exactly the kind of community where ADU demand has surged over the past several years.

The reasons Burlingame homeowners build ADUs mirror what we see across the Bay Area, but with a few local twists. Proximity to Caltrain makes rental ADUs especially attractive to commuters who want a Peninsula address without Peninsula rent. Multigenerational living is common: parents aging in place, adult children returning to the Bay Area, or extended family wanting to stay close without sharing a front door. And with Burlingame’s median home values among the highest in San Mateo County, the financial case for adding a rentable second unit to your property is straightforward.

California’s ADU laws have removed most of the regulatory barriers that once made these projects difficult. Burlingame updated its local ADU ordinance in late 2024 (Ordinance 2035) to align with state legislation, and the California Department of Housing and Community Development (HCD) has actively reviewed the city’s compliance. The result is a clearer, more predictable path from concept to construction.

This guide covers every requirement you need to know before starting an ADU project in Burlingame: zoning rules, size limits, setbacks, height restrictions, the permit process, design standards, and practical considerations specific to this city’s neighborhoods.

California State ADU Law: The Baseline

Before diving into Burlingame-specific rules, you need to understand the state framework. California’s ADU laws set the floor for what every city must allow. Local jurisdictions can be more permissive than state law, but they cannot be more restrictive.

The foundation was laid by three landmark bills between 2019 and 2020. AB 68 established the right to build both an ADU and a Junior ADU (JADU) on any residential lot, created the ministerial approval process, and eliminated replacement parking for garage conversions. SB 13 capped the permitting timeline at 60 days and reduced fees for smaller units. AB 881 limited the setback, lot coverage, and floor-area-ratio restrictions that cities could impose.

More recent legislation has strengthened these protections. AB 976 (effective January 2024) permanently removed owner-occupancy requirements for standard ADUs. SB 543 (effective January 2026) introduced a 15-business-day completeness review deadline, exempted ADUs under 500 square feet from school impact fees, and clarified that size limits are measured by interior livable space. AB 1033 allows ADU condo conversions in cities that opt in.

Together, these laws guarantee that you can build a detached ADU of at least 800 square feet on most residential lots in California, with four-foot side and rear setbacks, no replacement parking, and a 60-day approval deadline for complete applications. For a detailed breakdown of every state law currently in effect, see our California ADU laws guide.

Burlingame-Specific Zoning Rules

Burlingame permits ADUs across most residential zones, including R-1 (single-family), R-2 (two-family), and R-M (multi-family residential) districts. There is no minimum lot size requirement for building an ADU, which is consistent with state law.

Setbacks

All new ADUs must maintain four-foot side and rear setbacks, per California state law. No setbacks are required when you convert existing livable space or an existing accessory structure into an ADU, or when you build a new ADU in the same location and to the same dimensions as an existing structure you demolish for the purpose of building the ADU.

For non-statewide-exemption ADUs (those over 800 square feet), front setbacks follow the underlying zoning district requirements. However, statewide exemption ADUs (800 square feet or less) are exempt from front setback requirements. If there is no alternative location on your lot for an 800-square-foot ADU, state law allows the unit to encroach into the front setback.

For structures within 24 inches of a rear or side property line adjacent to a city alley or easement, Burlingame requires a boundary survey to confirm no encroachments exist.

Height Limits

Burlingame’s height limits follow the state framework:

• 16 feet for a detached ADU on a single-unit residential lot
• 18 feet if the lot is within one-half mile of a major transit stop or high-quality transit corridor, with an additional 2 feet allowed if the ADU’s roof pitch matches the primary dwelling
• 18 feet for a detached ADU on a lot with multi-unit dwellings
• 30 feet for an attached ADU (may not exceed two stories)
• 25 feet for an attached ADU in the Hillside Overlay zone (may not exceed two stories)

Given Burlingame’s proximity to the Burlingame Caltrain station and Broadway Caltrain station, many properties in the city likely fall within the half-mile transit corridor threshold. This means a number of Burlingame homeowners may qualify for the 18-foot height allowance on detached ADUs, which opens the door to two-story designs. Check with the City of Burlingame Community Development Department to confirm whether your specific property qualifies.

Lot Coverage and Floor Area Ratio

Statewide exemption ADUs (800 square feet or less) are fully exempt from lot coverage and floor area ratio (FAR) requirements. This is significant for Burlingame, where many residential lots are moderate in size and existing homes may already consume much of the allowable lot coverage.

Non-statewide-exemption ADUs (over 800 square feet) are subject to the FAR and lot coverage standards of the underlying zoning district. However, state law prevents the city from using these standards to deny an ADU of 800 square feet or less, regardless of how much coverage your primary home already uses.

Building Separation

Detached ADUs must meet building and fire code separation requirements from other structures on the lot. The specific distance depends on the building and fire code in effect, which is now the 2025 California Building Code effective January 1, 2026. Check with the Burlingame Building Division for the separation distance that applies to your project.

Types of ADUs Allowed in Burlingame

Detached ADUs

A detached ADU is a standalone structure, completely separate from the primary home. On single-family lots in Burlingame, you can build one detached ADU. These units can be up to 1,200 square feet under California state law, though Burlingame’s local ordinance distinguishes between two categories:

• Statewide exemption ADUs (800 square feet or less): Exempt from FAR, lot coverage, and front setback requirements. Four-foot side and rear setbacks apply. Maximum height of 16 feet, or 18 feet near major transit.
• Non-statewide-exemption ADUs (801 to 1,000 square feet of interior livable space): Cannot exceed 50% of the existing dwelling unit’s square footage. Subject to the underlying zoning district’s FAR and lot coverage limits.

Detached ADUs offer maximum privacy for both you and your tenants, and they typically command the highest rental rates. They are also the most expensive ADU type to build because they require a new foundation, full utility connections, and independent systems.

Attached ADUs

An attached ADU connects to the primary dwelling, sharing at least one wall. Height limits for attached ADUs in Burlingame are generous: up to 30 feet (25 feet in the Hillside Overlay), with a two-story maximum. This gives you more vertical flexibility than a detached unit.

Attached ADUs can reduce costs because they share some structural elements and utility connections with the main house. However, Burlingame requires attached ADUs to be separated from the primary dwelling by a minimum one-hour fire-resistance-rated wall, continuous from roof sheathing to foundation.

The same size limits apply: up to 1,000 square feet of interior livable space, and no more than 50% of the existing dwelling’s square footage for non-statewide-exemption units.

Junior ADUs (JADUs)

A Junior ADU is a unit of no more than 500 square feet of interior livable area, contained entirely within an existing or proposed single-unit dwelling. JADUs may include their own separate bathroom or share one with the primary residence. Multi-unit properties cannot have a JADU.

You can build both a detached ADU and a JADU on the same single-family lot, giving you up to three residential units on one property.

JADUs are the most affordable ADU type because they require no new foundation or roofing. The typical approach is to convert a bedroom, bonus room, or portion of an attached garage into an independent living unit with a small kitchenette and, ideally, its own bathroom.

Owner-occupancy rules for JADUs depend on bathroom configuration. If the JADU shares sanitation facilities with the main house, the owner must live in either the main home or the JADU. If the JADU has its own bathroom, no owner-occupancy requirement applies (per AB 1154, effective January 2026).

Garage Conversions

Converting an existing garage into an ADU is one of the most popular approaches in Burlingame. The existing structure provides the shell, so you skip the cost of a new foundation, framing, and roofing. Key requirements for garage conversions in Burlingame include:

• No replacement parking required. You do not need to build new parking when converting a garage, carport, or covered parking structure into an ADU.
• Foundation waterproofing. Garage conversions require waterproofing over the existing slab-on-grade foundation. Your plans must include details for vapor barrier installation and the ICC Evaluation Service Report number for the proposed waterproofing membrane.
• No setback requirements. Converting an existing garage into an ADU maintains the structure’s existing setbacks, even if they are less than four feet from the property line.

Garage doors must be removed and replaced as part of the conversion. The unit needs a separate, side-hinged entry and egress door independent of the primary dwelling.

Permit Process and Timeline

Burlingame processes all ADU permits ministerially. That means no public hearing, no discretionary design review by a commission, and no subjective judgment calls. If your plans meet the objective standards, the city must approve them.

How the Timeline Works

1. Pre-application. While not required, contacting Burlingame’s Community Development Department before submitting is smart. They can flag potential issues with your lot, confirm setback requirements, and clarify any site-specific concerns.

2. Application submission. Submit your complete ADU application to the Community Development Department. Under SB 543, the city must determine whether your application is complete within 15 business days of submission and provide a written list of any missing items. If they miss that deadline, your application is automatically deemed complete.

3. Plan review. Once your application is deemed complete, the city has 60 days to approve or deny your ADU permit. If the city does not act within 60 days, state law deems your application approved. During review, multiple departments weigh in: planning, building, fire (Central County Fire Department), engineering, and parks.

4. Permit issuance. After approval, the city issues your building permit. Prior to occupancy, a separate address for the ADU will be assigned, typically an alpha-numeric number with the letter “A” after the primary dwelling unit number.

5. Inspections. Construction inspections follow the standard building permit process. Under AB 1308 (effective January 2026), the city must complete final inspections within 10 business days after being notified that work is complete.

In practice, most Burlingame ADU permits are approved within three to four months from initial submission, assuming the application is complete and no significant revisions are needed.

What to Submit

A complete ADU application in Burlingame typically requires architectural plans, structural engineering, Title 24 energy calculations, and site plans showing the ADU location relative to property lines, existing structures, and easements. Your plans should identify all protected trees on the property (by botanical name and trunk diameter), address fire apparatus access, and include foundation and waterproofing details for garage conversions. Check with the Burlingame Building Division for the current submittal checklist.

Design Standards in Burlingame

Burlingame has historically maintained an active design review process for single-family homes. The city takes pride in the architectural character of its neighborhoods. However, California state ADU law overrides discretionary design review for ADU projects. The city cannot deny a compliant ADU based on subjective aesthetic preferences.

What the city can do is apply objective design standards. Here is what Burlingame currently requires:

• Permanent foundation. All ADUs must be built on a permanent foundation.
• No balconies, rooftop terraces, or second-story decks. This restriction applies to all ADU types, though state law limits the city’s ability to enforce this on statewide-exemption ADUs (800 square feet or less) that qualify under Government Code section 66323.
• Entrance orientation. Where possible, the entrance to the ADU should face the side or rear of the property rather than the same street as the main home’s entrance.
• Separate entry. ADUs must have a separate, side-hinged entry and egress door independent of the primary dwelling.
• Attached ADU fire separation. Attached ADUs require a minimum one-hour fire-resistance-rated wall separating the ADU from the primary dwelling. This wall must be continuous from roof sheathing to foundation, and your plans must include an assembly detail with a basis of approval (gypsum association file number or UL listing).
• Aging-in-place compliance. Newly constructed detached ADUs must comply with aging-in-place requirements per California Residential Code Section R327. This includes features like wider doorways, blocking for future grab bars, and accessible bathroom layouts.

For statewide-exemption ADUs (800 square feet or less), the city is limited in the objective standards it can impose. The state does not allow cities to apply development or design standards beyond what state law specifically authorizes for these smaller units. This means that if your ADU is 800 square feet or less and meets state-mandated setback and height requirements, the city has very little room to impose additional design conditions.

Small Lot Considerations

Burlingame’s residential lots are generally moderate in size compared to cities like Saratoga or Danville, where half-acre and one-acre parcels are common. Many Burlingame neighborhoods feature lots in the 5,000 to 7,500 square foot range, which means ADU placement requires more careful planning.

The good news: California’s statewide exemption guarantees your right to build an ADU of at least 800 square feet regardless of how much lot coverage or FAR your existing home uses. The city cannot deny an 800-square-foot ADU based on lot coverage limits, floor area ratio restrictions, or even front setback requirements if there is no alternative location on the lot. This protection is critical for smaller Burlingame lots where the primary home may already consume most of the allowable building envelope.

To maximize ADU size on a tighter lot, consider these strategies:

• Garage conversion. Converting an existing garage avoids consuming additional lot area and uses existing setbacks, which may be less than four feet.
• Two-story detached. If your lot is within half a mile of a major transit stop, you can build up to 18 feet tall, which allows a two-story layout. Going vertical lets you get more square footage from a smaller building footprint.
• Attached ADU. Building onto the primary home uses shared walls and foundations, reducing the footprint impact. Attached ADUs in Burlingame can be up to 30 feet tall and two stories.
• Right-size your unit. Staying at or under 800 square feet gives you the full statewide exemption from FAR, lot coverage, and front setback requirements. This is often the sweet spot for Burlingame lots.

If your lot is particularly constrained, a pre-application consultation with the Community Development Department can help you understand exactly what will fit before you invest in architectural plans.

Estimated Permit Fees

Burlingame’s ADU permit fees include building permit fees, plan check fees, and potentially impact fees depending on the size of your unit. The research available does not provide specific Burlingame fee amounts, so we recommend the following approach:

• ADUs 750 square feet or less: Exempt from development impact fees under California law. ADUs and JADUs under 500 square feet are also exempt from school impact fees (per SB 543).
• ADUs over 750 square feet: Subject to proportional development impact fees based on the size of the ADU relative to the primary dwelling. School impact fees apply at standard district rates.
• Utility connections: For detached ADUs, you will need independent utility connections for water, sewer, and electrical. Burlingame requires sewer laterals for ADUs to tie in to existing sewer laterals; no sub-laterals are permitted. Budget $5,000 to $15,000 for utility connections depending on your lot configuration and distance from existing infrastructure.
• Building permit and plan review fees: These vary by project scope and valuation. Contact the Burlingame Building Division at 650-558-7260 or buildingpermits@burlingame.org for the current fee schedule.

In total, soft costs for a Burlingame ADU project (including design, engineering, permits, fees, and utility connections) typically range from $20,000 to $55,000 on top of construction costs. This is consistent with other Peninsula cities in San Mateo County.

Common Pitfalls for Burlingame ADU Projects

Protected Tree Requirements

Burlingame takes its tree canopy seriously. When your ADU creates new square footage, the city reviews protected tree impacts. Protected trees, as defined in Municipal Code Chapter 11.06, on your property, in the public right of way, or on any neighboring property overhanging onto yours must be identified on your plans by botanical name (genus and species) and trunk diameter measured at 54 inches from grade.

A tree protection plan prepared by a qualified ISA Certified Arborist is required for all protected trees that will remain. Protected trees may not be removed, structurally altered, or excessively pruned (roots or crown) without a Protected Tree Permit from the Parks Division. Trees approved for removal must remain in place until building permit issuance. If your ADU footprint conflicts with a significant tree, plan for this early: arborist reports take time and tree removal permits add steps to your timeline.

Sewer and Utility Complications on Older Lots

Many Burlingame homes were built in the early to mid-twentieth century, and their utility infrastructure reflects that era. Sewer laterals may be undersized, aging, or in unexpected locations. Burlingame requires ADU sewer laterals to tie in to existing laterals with no sub-laterals permitted. If your existing lateral is in poor condition, you may need to replace it before connecting the ADU, which adds cost and time.

Detached ADUs also require that occupants have ready access to the electrical panel, a separate heating system, and direct access to the water heater. Plan for independent mechanical systems from the start to avoid redesign during plan review.

Setback Miscalculations on Narrow Lots

On narrower Burlingame lots, even a few inches of error in setback calculations can mean the difference between approval and a plan revision. If your proposed structure is within 24 inches of a property line adjacent to a city alley or easement, a boundary survey is required to confirm no encroachments. Invest in an accurate property survey early. It costs $2,000 to $5,000 but prevents costly redesigns later.

Fire Access Requirements

Burlingame is served by the Central County Fire Department, which requires fire apparatus access within 150 feet of a public way (street or fire access driveway) to the furthest portion of the ADU. This distance is measured along the pedestrian access path and cannot pass through landscaping (except lawn), over pools, through fences, or over retaining walls. On deeper lots, meeting this requirement may constrain where you can place a detached ADU. Confirm fire access compliance before finalizing your site plan.

Flood Zone Complications

Properties within the Special Flood Hazard Area must have the finish floor constructed one foot above the Base Flood Elevation (BFE). This can significantly increase foundation costs for detached ADUs in affected areas. Check FEMA flood maps for your property before beginning design.

Build Your Burlingame ADU with Custom Home

Burlingame’s combination of strong rental demand, Caltrain access, and established neighborhoods makes it an excellent market for ADU investment. The regulatory path is clearer than ever, with state law providing strong protections for homeowners and Burlingame’s updated ordinance aligning with those standards.

The key to a successful ADU project in this city is working with a team that understands both the state framework and Burlingame’s specific requirements: tree protections, fire access, sewer tie-in rules, and the practical realities of building on moderate-sized Peninsula lots.

Custom Home Design and Build has been constructing ADUs and custom homes across the Bay Area since 2005. Our design-build process means one team handles architecture, permitting, and construction, so nothing falls through the cracks between disciplines.

Ready to explore what you can build on your Burlingame property? Contact us for a free consultation and we will assess your lot, walk you through the requirements, and give you a realistic plan for your ADU project.