California ADU Laws 2026: Rules, Permits & New Changes

California's ADU laws changed significantly on January 1, 2026. Four new bills rewrote how permits are processed, how fees are calculated, and what homeowners can build in the Coastal Zone. This guide covers every change that matters — from permit timelines to impact fees to selling your ADU as a condominium — and links to our detailed analyses on each topic.

Bottom Line

Four bills signed by Governor Newsom in late 2025 reshape California's ADU rules effective January 1, 2026:

SB 543 codifies the 60-day permit approval clock, mandates a 15-business-day completeness review, redefines size thresholds using "interior livable space," and exempts ADUs under 750 sq ft from impact fees. [1]
AB 1154 updates JADU owner-occupancy rules — if the JADU has independent sanitation facilities, owner-occupancy is no longer required. [2]
AB 462 (urgency statute, effective October 15, 2025) imposes a 60-day shot clock on Coastal Development Permits for ADUs, eliminates appeals to the Coastal Commission, and creates post-disaster occupancy provisions. [3]
AB 434 requires every California city to offer pre-approved ADU plans by January 1, 2026. [4]

What these mean in practice:

Permit timelines are now enforceable — cities that miss the 60-day deadline face deemed-approved consequences.
Impact fees are eliminated for ADUs under 750 sq ft of interior livable space, and school fees are eliminated for units under 500 sq ft.
Coastal ADU permits that once took 12–18 months can now be completed in 60 days.
The "1+1+1" strategy — a conversion ADU, a detached ADU, and a JADU on a single lot — is confirmed as a legal right under state law.
HCD has expanded enforcement authority to void non-compliant local ordinances.
Pre-approved plans are available statewide, reducing design costs and approval times.

What Changed in California ADU Law for 2026

The 2026 ADU law cycle marks a shift from policy guidance to enforcement. Previous rounds of legislation (SB 13, AB 68, AB 881, AB 976) established the framework. The 2026 bills close the gaps that allowed local agencies to delay, deny, or add conditions beyond what state law permits.

The Department of Housing and Community Development (HCD) documented over 50 local governments incorrectly applying state ADU/JADU laws prior to 2026. [5] SB 543 was sponsored by the Casita Coalition and passed with overwhelming bipartisan support — 39-0 in the Senate and 75-0 in the Assembly — specifically to eliminate this non-compliance. [6]

Here is what changed and what stayed the same:

The cumulative effect is significant. California is no longer asking local agencies to voluntarily comply with ADU law. It is telling them — with deadlines, measurement standards, and enforcement teeth.

How ADU Permits Work in 2026

The permitting process is the single biggest source of delay and frustration for ADU projects. SB 543 restructures the timeline into three enforceable stages.

The 15-Business-Day Completeness Rule (SB 543)

When you submit an ADU or JADU application, the permitting agency now has exactly 15 business days to determine whether your application is complete and provide written notice. [1]

If the application is deemed incomplete, the agency must provide:

A detailed list of every incomplete item
A clear description of how the application can be made complete [9]

This is the "one-and-done" rule. The agency cannot issue vague feedback, ask for items one at a time over multiple rounds, or leave your application in limbo without response. If they determine your application is incomplete, they must tell you everything that is missing in a single notice.

If you disagree with an incompleteness determination, SB 543 establishes a formal appeal process. The agency must issue a final written decision on your appeal within 60 business days. [9]

The 60-Day Approval Clock

Once your application is deemed complete, the permitting agency has 60 days to approve or deny it. [1] This timeline applies to all ADU and JADU applications statewide, including those on multifamily properties.

The enforcement mechanism is what makes this different from prior law: if the agency fails to act within 60 days, the application is deemed approved as a matter of law. [10] This shifts the risk from the applicant to the agency — a city that sits on a complete application for 61 days has effectively issued a permit.

Combining these two rules, the maximum timeline from application submission to permit decision is approximately 75 business days (15 for completeness review + 60 for approval), assuming a complete initial application.

Pre-Approved Plans Are Now Statewide (AB 434)

AB 434 requires every California city and county to offer at least one set of pre-approved ADU plans by January 1, 2026. [4] Pre-approved plans bypass much of the plan check process because the design has already been reviewed and approved by the jurisdiction.

Benefits of using pre-approved plans:

Faster permit processing (often under 30 days)
Lower design costs ($0 to $5,000 versus $8,000 to $20,000 for custom plans)
Reduced risk of incompleteness determinations
Standardized construction that contractors can bid more accurately

The trade-off is design flexibility. Pre-approved plans are typically available in a limited number of configurations (studio, one-bedroom, two-bedroom) and may not accommodate unusual lot shapes, slopes, or architectural preferences.

For a deeper analysis of how these permit timelines work in practice, including incompleteness appeals and deemed-approved procedures, see our detailed SB 543 analysis.

What You Can Build — Size, Setbacks & Height Rules

California's ADU law establishes a "safe harbor" — a set of minimum development standards that every city must allow, regardless of local zoning. Cities can be more permissive, but they cannot be more restrictive than state law on these core parameters. [9]

The 800 Square Foot Safe Harbor

Under Government Code Section 66323, every California city must ministerially approve an ADU that meets the following standards: [11]

Size: Up to 800 square feet of interior livable space
Height: Up to 16 feet (18 feet if the ADU includes a second story)
Setbacks: 4 feet from side and rear property lines
Lot coverage: Cannot be used as a basis for denial if the ADU meets the size, height, and setback standards above

SB 543 clarified that the 800 sq ft threshold refers to interior livable space — the area intended for human habitation, including living, sleeping, eating, cooking, and sanitation. [1] This excludes exterior walls, non-habitable storage areas, and stairways. A building with an 860 sq ft footprint could measure under 800 sq ft of interior livable space after accounting for wall thickness and non-habitable areas.

Many cities allow larger ADUs than the state minimum. Los Angeles, for example, permits ADUs up to 1,200 sq ft depending on the lot and zoning context. [12] San Jose allows up to 1,000 sq ft for detached ADUs. The 800 sq ft safe harbor is a floor, not a ceiling.

Multi-ADU Combinations on One Lot

One of the most powerful features of California ADU law is the ability to build multiple unit types on a single lot. On a single-family property, state law allows:

One conversion/attached ADU — converting an existing garage, basement, or other accessory structure
One new detached ADU — up to 800 sq ft with 4-foot setbacks
One JADU — up to 500 sq ft of interior livable space, contained within the primary residence

This "1+1+1" combination is not a loophole or an aggressive interpretation. It is explicitly described in Government Code Section 66323, and SB 543 confirmed that local agencies must allow these combinations ministerially. [11][1]

On multifamily properties, the allowances are even more generous. SB 1211 (effective 2025) permits up to 8 detached ADUs on multifamily lots, plus internal conversions of non-habitable spaces (at least one, up to 25% of existing units). [13] These internal and external allowances are cumulative — cities cannot force owners to choose between them.

For a strategic breakdown of how to combine SB 543's ADU provisions with SB 9 lot splits for maximum development potential, see our SB 543 + SB 9 compound strategy guide.

ADU vs JADU — Key Differences in 2026

ADUs and JADUs are governed by related but distinct sections of the Government Code, and the differences matter for cost, design, and rental strategy.

JADUs are particularly attractive for homeowners who want to add a unit with minimal construction cost. Converting a bedroom or portion of a garage into a JADU with an efficiency kitchen and a separate entrance can cost $30,000 to $80,000 — a fraction of detached ADU construction. And under the 2026 rules, a JADU under 500 sq ft pays zero impact fees and zero school fees.

ADU Fees in 2026 — Two Thresholds That Save Thousands

Impact fees are one of the largest controllable costs in an ADU project budget. California law creates two size-based exemptions that can save $10,000 or more — but only if you design to the right threshold.

The 750 Sq Ft Impact Fee Exemption

Government Code Section 66311.5 (renumbered from Section 66324 by SB 543) states that no local agency, special district, or water corporation may impose any impact fee on an ADU of 750 square feet or less of interior livable space. [7]

For ADUs above 750 square feet, impact fees must be calculated proportionally relative to the square footage of the primary dwelling. [7] This means an 800 sq ft ADU on a property with a 2,000 sq ft primary residence would pay 40% of the impact fees that a new 2,000 sq ft home would trigger.

Fees covered by this exemption include: park and recreation fees (Quimby Act), transportation impact fees, fire facility fees, library fees, general infrastructure fees, and affordable housing impact fees. [7]

Fees not covered by this exemption (they always apply regardless of size): water and sewer connection fees, capacity charges, building permit processing fees, and plan check fees. [7]

The 500 Sq Ft School Fee Exemption (New in 2026)

SB 543 added a second threshold specifically for school developer fees. ADUs and JADUs containing less than 500 square feet of interior livable space are exempt from school fees under Education Code Section 17620. [8]

For ADUs between 500 and 750 sq ft, impact fees are waived under Government Code, but school districts may still levy school developer fees. The current statewide Level 1 school fee rate is $5.38 per square foot for residential construction. [15] A 600 sq ft ADU could face school fees of approximately $3,228 while paying zero impact fees. A 499 sq ft ADU pays neither.

Fees That Always Apply

Regardless of size, every ADU project must pay:

Water and sewer connection fees: Typically $2,000 to $10,000 depending on jurisdiction and whether the ADU requires a new or upgraded connection. [16]
Building permit fees: Usually based on project valuation, ranging from $1,000 to $5,000.
Plan check fees: Typically 65% to 80% of the building permit fee.
Utility panel upgrades: If your existing electrical panel cannot support the additional load, upgrading costs $2,000 to $4,000. [16]

These fees are not waivable because they cover the actual cost of connecting your ADU to infrastructure, not the speculative cost of future public facilities.

For a complete breakdown of what six major California cities actually charge, including San Jose, Los Angeles, San Diego, Oakland, and Sacramento, see our complete guide to ADU impact fees.

Parking, Owner-Occupancy & Rental Rules

Parking requirements and owner-occupancy rules are two of the most common questions homeowners ask when planning an ADU. The 2026 rules are more permissive than many people realize.

When Parking Is Not Required

California law prohibits local agencies from requiring parking for an ADU in the following situations: [11]

The ADU is located within half a mile of a public transit stop (bus, rail, ferry)
The ADU is within an architecturally and historically significant historic district
The ADU is part of an existing primary residence or accessory structure (conversion)
On-street parking permits are required but not offered to the ADU occupant
The ADU is located within one block of a car-share vehicle pickup/drop-off location

When parking is required, the maximum a city can demand is one space per ADU, which may be provided as tandem parking on an existing driveway or in setback areas. [11]

In practice, most urban and suburban ADUs in California qualify for at least one of these exemptions. The half-mile transit rule alone covers the majority of residential lots in cities like Los Angeles, San Francisco, San Jose, and San Diego.

Owner-Occupancy Rules — The 2026 Update

The owner-occupancy rules changed twice in recent years. SB 13 (2019) temporarily suspended the owner-occupancy requirement for ADUs, and AB 976 (signed 2023, effective 2024) made that elimination permanent — allowing homeowners to rent out both their primary residence and their ADU simultaneously. [17] This was a major shift that made ADUs viable as pure investment properties.

JADUs, however, retained an owner-occupancy requirement. Until 2026, the property owner (or a close family member in some jurisdictions) was required to live in either the primary residence or the JADU.

AB 1154 (effective January 1, 2026) introduces a nuance: [2]

If the JADU shares sanitation facilities with the primary residence (i.e., JADU occupants use the main house bathroom), owner-occupancy is still required for either the JADU or the primary dwelling.
If the JADU has its own independent sanitation facilities, owner-occupancy is no longer required.

This is a meaningful change for investors. A JADU with its own bathroom and efficiency kitchen — essentially a self-contained small apartment within the primary structure — can now be rented out on a property where the owner does not live. Combined with ADU rules, this means a single-family lot could potentially have three rental units (primary residence, ADU, and JADU) with no owner-occupancy requirement, as long as the JADU has independent sanitation.

All ADUs and JADUs must be rented for terms of 30 days or longer. Short-term rentals (Airbnb, VRBO) are prohibited under state law. [14]

Coastal Zone ADUs — A Breakthrough Year (AB 462)

Before AB 462, building an ADU in California's Coastal Zone was an exercise in patience and frustration. Coastal Development Permits (CDPs) were processed separately from building permits, often took 12 to 18 months, and could be appealed to the California Coastal Commission by third parties — adding months or years of uncertainty. [3]

AB 462, signed as an urgency statute on October 15, 2025, changed three things simultaneously:

60-Day Shot Clock: Local agencies must approve or deny a completed CDP application for an ADU within 60 days. If they fail to act, the permit is deemed approved. [3]

No Coastal Commission Appeals: The ability to appeal a local agency's CDP decision to the California Coastal Commission is eliminated for ADU projects. This removes what had been the single biggest source of delay and uncertainty for coastal ADU builders. [3]

Concurrent Processing: The CDP review must run concurrently with standard ADU planning and building permit review, not sequentially. [18] This alone can eliminate months of waiting.

Post-Disaster Occupancy: AB 462 creates a narrow but important exception for detached ADUs in counties subject to a Governor-declared state of emergency (on or after February 1, 2025). If the primary dwelling was substantially damaged or destroyed and the ADU has passed all required inspections, the local agency must issue a certificate of occupancy for the ADU — allowing residents to live on their property while the primary home is rebuilt. [3]

This provision was designed in direct response to the wildfire disasters that have affected California in recent years. A homeowner whose house burns down can move into their ADU (or build one) without waiting for the primary residence to be reconstructed first.

For the full analysis of AB 462, including case studies from Santa Cruz and other coastal jurisdictions, see our AB 462 coastal ADU breakdown.

Selling Your ADU — AB 1033 Condominium Conversion

One of the most significant pieces of California's ADU legislation is AB 1033, which allows homeowners to sell an ADU separately from the primary residence through a condominium conversion process. [19]

Under AB 1033, a local agency can adopt an ordinance allowing ADUs to be converted into condominiums and sold as separate legal units. The process requires:

A condominium map or parcel map
CC&Rs (Covenants, Conditions, and Restrictions) governing shared elements
Compliance with all applicable building codes and ADU regulations
A local ordinance opting into the program

This is not automatic. Your city must affirmatively adopt an AB 1033 ordinance. As of early 2026, several cities are in the process of developing these ordinances, with early adopters expected to begin processing applications in mid-2026. [19]

The financial implications are substantial. In many California markets, a detached ADU that might rent for $2,000 per month ($24,000 annually) could sell as a condominium for $300,000 to $500,000 — representing a significantly different investment calculus than rental income alone.

However, AB 1033 sales come with complexities: shared utility infrastructure, shared lot access, HOA-like governance structures, and title insurance considerations that do not exist in standard single-family sales. [19]

For a full walkthrough of the AB 1033 condominium conversion process, including legal requirements, financial modeling, and early city adoption status, see our detailed guide to AB 1033.

2026 Building Code Changes That Affect Every ADU

The 2025 edition of California's Title 24 Building Standards Code took effect on January 1, 2026, and introduces several changes that directly affect ADU design and construction costs. [20]

Energy Code (Title 24 Part 6): The updated energy code increases insulation requirements, mandates higher-efficiency HVAC systems, and continues California's push toward all-electric construction. Heat pump water heaters and heat pump space conditioning systems are now the default pathway for code compliance in most climate zones. An ADU designed with a gas furnace and gas water heater will face significantly higher compliance costs through alternative performance trade-offs. [20]

All-Electric Readiness: While not all jurisdictions mandate all-electric construction for ADUs, the energy code makes electric the path of least resistance. Solar photovoltaic requirements apply to ADUs in most cases, adding $5,000 to $10,000 to construction costs but reducing long-term operating expenses. [20]

CALGreen (Title 24 Part 11): Mandatory green building requirements include EV-ready parking (if a parking space is provided), water-efficient fixtures, and construction waste diversion. These apply to ADUs as they do to any new residential construction. [20]

Structural Loads (ASCE 7-22): Updated wind and seismic load requirements under ASCE 7-22 may increase structural costs for ADUs in high-wind or high-seismic zones. The practical impact varies by location — coastal and hilltop ADUs may see the largest cost increases. [20]

Wildland-Urban Interface (WUI): ADUs in WUI zones face additional fire-resistant construction requirements, including ignition-resistant exterior materials, ember-resistant vents, and defensible space. These requirements can add $10,000 to $30,000 to construction costs depending on the fire severity zone. [20]

For a detailed technical breakdown of every 2026 code change affecting ADU projects, see our 2026 building standards update.

ADU Costs in 2026 — What to Realistically Expect

ADU construction costs in California have risen steadily and continue to trend upward. The Construction Cost Index rose 44% between January 2021 and December 2025. [21] Homeowners planning a 2026 project should budget accordingly.

Typical cost ranges for a standard detached ADU in 2026:

| ADU Type | Typical Cost Range | | :--- | :--- | | Garage conversion | $80,000 – $180,000 | | JADU (internal conversion) | $30,000 – $80,000 | | Small detached (400–500 sq ft) | $180,000 – $280,000 | | Medium detached (600–800 sq ft) | $250,000 – $400,000 | | Large detached (800–1,200 sq ft) | $350,000 – $500,000+ | | Prefab/modular (delivered and installed) | $200,000 – $400,000 |

These ranges include permits, design, site work, utility connections, and construction, but exclude land cost and financing expenses.

Why smaller ADUs cost more per square foot: Every ADU requires a full kitchen, a full bathroom, a foundation, utility hookups, solar panels, and a complete permit set — regardless of size. These fixed costs create a floor. A 400 sq ft studio can cost $375 to $600+ per square foot, while a 1,200 sq ft two-bedroom runs $150 to $300 per square foot. [21]

Financing options in 2026 include:

Home equity loans (HELOCs): The most common financing method, using equity in the primary residence
Construction loans: Short-term loans that convert to permanent financing after completion
Cash-out refinance: Replacing an existing mortgage with a larger one to fund construction
ADU-specific loan products: Several California lenders now offer loan products designed specifically for ADU construction, with underwriting that considers projected rental income
CalHFA ADU Grant Program: State grants of up to $40,000 for qualifying homeowners (income-restricted, availability varies) [22]

Prefab vs. custom-built: The price gap between prefab and custom ADUs has narrowed significantly. Factory-built units save time (weeks instead of months for the structure), but after adding transportation, crane placement ($5,000–$15,000), foundation work, site preparation, and utility connections, total costs are comparable to stick-built construction. Choose prefab for timeline compression, not cost savings. [21]

For a detailed analysis of ADU cost dynamics, including the 750 sq ft fee cliff, the second-bedroom ROI, and why waiting costs money, see 13 counterintuitive truths about ADU costs.

What Happens When Your City Says No — HCD Enforcement

One of the most consequential changes in California's 2026 ADU framework is the expansion of HCD's enforcement authority. The Department of Housing and Community Development is no longer limited to issuing guidance letters that cities can ignore. [9]

Under SB 543 and prior legislation, HCD's enforcement powers include:

Ordinance Review: Every local ADU and JADU ordinance must be submitted to HCD for review within 60 days of adoption. HCD examines whether the ordinance complies with state law. [9]

Findings of Non-Compliance: If HCD determines that a local ordinance does not comply, it issues written findings specifying the violations. The local agency has 30 days to respond with either amendments or a legal justification. [9]

Automatic Voiding: If a local agency fails to submit an adopted ordinance to HCD within the required timeline, or fails to respond to HCD's findings of non-compliance within 30 days, the ordinance is deemed null and void. The local agency must then process all ADU applications directly under state law, with no local modifications. [9]

Technical Assistance: HCD also provides technical assistance to local agencies developing or amending ADU ordinances. Cities that proactively consult with HCD during ordinance development are less likely to face compliance issues.

Practical implications for homeowners: If your city denies your ADU application based on a local ordinance provision that conflicts with state law, you have recourse. You can file a complaint with HCD, which will review the local ordinance and issue findings. If the city's rule is found to violate state law, the city must process your application under the more permissive state standards.

This enforcement mechanism is not theoretical. HCD has reviewed dozens of local ordinances since 2020 and has compelled multiple cities to amend their ADU rules. [5] The 2026 legislation strengthens this process by making timelines and consequences more explicit.

Frequently Asked Questions

What are the new California ADU laws for 2026?

Four bills signed in 2025 take effect in 2026: SB 543 codifies permit timelines, size definitions, and fee exemptions into enforceable state law. AB 1154 updates JADU owner-occupancy rules. AB 462 (effective October 15, 2025) streamlines coastal ADU permits. AB 434 requires all cities to offer pre-approved ADU plans. Together, these bills shift California's approach from voluntary guidance to mandatory compliance with clear enforcement consequences. [1][2][3][4]

How long does it take to get an ADU permit in California in 2026?

Under SB 543, the permitting agency has 15 business days to determine whether your application is complete, then 60 days to approve or deny a complete application. The maximum timeline from submission to decision is approximately 75 business days for a complete initial submission. If the agency misses the 60-day deadline, your application is deemed approved. [1][10] Projects using pre-approved plans may be processed faster — some jurisdictions report turnaround times under 30 days for standard plan applications.

Do I need to live on my property to have an ADU in California?

For ADUs: No. AB 976 (effective 2024) permanently eliminated the owner-occupancy requirement for ADUs. You can rent out both your primary residence and your ADU without living on the property. [17] For JADUs: It depends. Under AB 1154 (2026), owner-occupancy is required only if the JADU shares sanitation facilities with the primary residence. If the JADU has its own bathroom, no owner-occupancy is required. [2]

What is the maximum size for an ADU in California?

State law guarantees a minimum right to build an ADU of 800 square feet of interior livable space (the "safe harbor"), with 4-foot setbacks and up to 16 feet in height. [11] Many cities allow larger ADUs — Los Angeles permits up to 1,200 sq ft, and other jurisdictions may allow more depending on lot size and zoning. [12] JADUs are limited to 500 square feet of interior livable space and must be contained within the primary residence. [14]

How much do ADU impact fees cost in California in 2026?

For ADUs under 750 square feet of interior livable space: zero impact fees under Government Code Section 66311.5. [7] For ADUs under 500 square feet: also zero school developer fees under Education Code Section 17620. [8] For ADUs above 750 square feet, impact fees are calculated proportionally relative to the primary dwelling. In cities like Los Angeles, crossing the 750 sq ft threshold can add $5,000 to $15,000 or more in fees. Water and sewer connection fees ($2,000–$10,000) and building permit fees always apply regardless of size. [16]

Can I build an ADU in the California Coastal Zone?

Yes. AB 462 (effective October 15, 2025) created a 60-day approval timeline for Coastal Development Permits for ADUs, eliminated appeals to the California Coastal Commission, and allows concurrent processing with building permits. [3] The same state ADU development standards (size, setbacks, height) apply in the Coastal Zone. Your ADU still must comply with any applicable Local Coastal Program provisions that do not conflict with state ADU law. This is a dramatic improvement — coastal ADU permits that previously took over a year can now be completed in roughly two months.

Can I sell my ADU separately from my house in California?

Potentially, yes — but only if your city has adopted an AB 1033 ordinance allowing ADU-to-condominium conversion. [19] AB 1033 creates a legal pathway to subdivide your property into condominium units, allowing the ADU to be sold independently. This requires a condominium map, CC&Rs, and compliance with local ordinance requirements. As of early 2026, several cities are developing AB 1033 ordinances, with the first applications expected in mid-2026. Not all cities will opt in.

What happens if my city denies my ADU application incorrectly?

You have several options. First, if your application was deemed incomplete, SB 543 provides a formal appeal process with a 60-business-day decision timeline. [9] Second, you can file a complaint with HCD, which has the authority to review local ordinances and compel compliance with state law. If HCD finds that your city's denial was based on a provision that conflicts with state ADU law, the city must process your application under state standards. [5] Third, if the permitting agency fails to act within the 60-day approval timeline, your application is deemed approved as a matter of law. [10] The 2026 framework is designed to ensure that cities cannot use delay, ambiguity, or non-compliant local rules to block ADU projects that comply with state law.

Sources

[1] SB 543 Bill Text (McNerney, signed Oct 10, 2025): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260SB543

[2] California YIMBY. "California Law Makes it Easier to Build Small, In-Home ADUs" (AB 1154 analysis): https://cayimby.org/news-events/press-releases/california-law-makes-it-easier-to-build-small-in-home-adus/

[3] AB 462 Bill Text (Lowenthal/Rivas, urgency statute, signed Oct 15, 2025): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260AB462

[4] AB 434 Bill Text (Pre-approved ADU plans mandate): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202320240AB434

[5] California Department of Housing and Community Development. "ADU and JADU — Compliance and Enforcement": https://www.hcd.ca.gov/policy-and-research/accessory-dwelling-units

[6] California YIMBY. "SB 543: ADU Clarity and Consistency": https://cayimby.org/legislation/sb-543/

[7] California Government Code Section 66311.5 (ADU impact fee exemptions, renumbered by SB 543): https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=66311.5

[8] Dannis Woliver Kelley. "SB 543 Exempts Certain Accessory Dwelling Units From School Impact Fees": https://www.dwkesq.com/sb-543-exempts-certain-accessory-dwelling-units-from-school-impact-fees/

[9] California Department of Housing and Community Development. "Addendum to Accessory Dwelling Unit Handbook." January 2026: https://www.hcd.ca.gov/building-standards/adu

[10] Best Best & Krieger LLP. "Governor Newsom Signs Four New Accessory Dwelling Unit Bills." November 7, 2025: https://bbklaw.com/resources/la-110725-governor-newsom-signs-four-new-accessory-dwelling-unit-bills

[11] California Government Code Section 66323 (ADU ministerial approval provisions): https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=66323.

[12] City of Los Angeles Department of City Planning. ADU Resources and Guidelines: https://planning.lacity.gov/plans-policies/accessory-dwelling-units

[13] SB 1211 Bill Text (Multifamily ADU allowances, 2024): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202320240SB1211

[14] California Government Code Section 66323 (JADU provisions) and Section 66323.5: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=66323.

[15] AALRR. "SAB Increases Statutory Level 1 Developer Fees to $5.38": https://www.aalrr.com/newsroom-alerts-4204

[16] ADU Marketing Pros. "ADU Permit Cost California": https://adumarketingpros.com/real-estate/adu-permit-cost-california/

[17] AB 976 Bill Text (Owner-occupancy elimination for ADUs, 2024 effective date): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202320240AB976

[18] Holland & Knight. "California's 2026 Housing Laws: What You Need to Know." December 11, 2025: https://www.hklaw.com/en/insights/publications/2025/12/californias-2026-housing-laws-what-you-need-to-know

[19] AB 1033 Bill Text (ADU condominium conversion): https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202320240AB1033

[20] California Building Standards Commission. 2025 Title 24 California Building Standards Code: https://www.dgs.ca.gov/BSC/Codes

[21] SnapADU. "How Much Does an ADU Cost?": https://www.snapadu.com/how-much-does-an-adu-cost

[22] CalHFA. ADU Grant Program: https://www.calhfa.ca.gov/homebuyer/adu/

Planning an ADU project in California? ADU Pilot provides site-specific feasibility analysis, constraint mapping, and fee estimates for your property — so you can move from research to permit with confidence.