How Much Do ADU Permits Cost in California? A Comprehensive Guide

If you’re thinking about building an ADU in California, you’re probably wondering the same thing most homeowners do: How much does an ADU permit cost? You’re not alone permit fees are one of the most confusing and frustrating parts of the process. From city regulations to hidden fees, it can feel like a maze.

But here’s the truth: thousands of Californians go through this same challenge every year. And with the right guidance, you don’t have to feel overwhelmed or overcharged. Understanding your ADU permit cost upfront, including factors like 500 sq ft ADU cost or 600 sq ft ADU cost, can save you time, money, and major headaches down the road. Whether you’re in Los Angeles, San Diego, or even Riverside County, getting clear on permit cost for ADU early on is the first step toward a smooth construction process.

In this article, we’ll break down the different ADU permit fees you might encounter in California, explain how to calculate these costs, and provide insights into the factors that influence your total expenses. By the end, you’ll know exactly what to expect, ensuring you can confidently plan your ADU project without unexpected costs or delays.

Ready to dive in? Let’s take a closer look at the details!

---

Do I Need a Permit to Build an ADU in California?

Building an Accessory Dwelling Unit (ADU) in California is an exciting project, but before you start breaking ground, it’s crucial to understand the legal requirements, especially the permit process. In most cases, you will need a permit to ensure that your ADU complies with local building codes, zoning laws, and safety standards. Let’s take a closer look at the general permit requirements that you’ll need to follow to legally build your ADU in California.

General Permit Requirements in California

If you’re planning to build an Accessory Dwelling Unit (ADU) in California, the short answer is: yes, you will almost certainly need a permit. Permits are crucial because they ensure that your ADU project complies with local building codes, zoning laws, and safety regulations. Without them, your project could face legal issues, fines, or delays.

In most cases, to build an ADU, you will need the following permits:

1. Building Permit: This is the primary permit required for any structure. It ensures the ADU will be structurally sound and meet safety requirements.
2. Planning Approval: This permit ensures your project complies with local zoning regulations, such as setback requirements, height restrictions, and land use.
3. Utility Connection Permits: If your ADU needs connections to essential utilities like water, electricity, sewer, or gas, you’ll need permits for each. In California, each utility company may have specific connection requirements and fees.

While these are the standard permits required, the exact process and fees can vary by location, so it’s essential to check with your local city or county office.

City/County	Building Permit	Planning Approval	Utility Connection Permits	Total Estimated Cost	Why Costs Vary
Los Angeles	$3,000 – $5,000	$1,000 – $2,500	$500 – $1,500	$4,500 – $9,000	Los Angeles has high construction costs due to urban density and stricter zoning regulations. Utility connection fees are also higher due to the city’s extensive infrastructure.
San Francisco	$4,000 – $6,000	$1,500 – $3,000	$700 – $2,000	$6,200 – $11,000	San Francisco is known for its high land value and strict zoning laws, driving up both planning approval and utility costs. The city also has more complex infrastructure.
San Diego	$2,500 – $4,500	$800 – $2,000	$400 – $1,200	$3,700 – $7,700	San Diego offers more affordable permits compared to Los Angeles and San Francisco, with relatively fewer zoning restrictions and lower utility connection fees.
Riverside County	$2,000 – $3,500	$500 – $1,500	$300 – $1,000	$2,800 – $6,000	Riverside has more affordable costs due to its rural nature and less densely populated areas. Fewer zoning restrictions contribute to lower overall costs.
Sacramento	$2,500 – $4,000	$1,000 – $1,800	$350 – $1,000	$3,850 – $6,800	Sacramento has lower overall fees compared to coastal cities, as it is less densely populated and has fewer infrastructure demands.
Orange County	$3,000 – $5,500	$1,200 – $2,500	$400 – $1,500	$4,600 – $9,500	Similar to Los Angeles, Orange County has higher permit fees due to urban sprawl, higher demand for utilities, and stricter zoning requirements.
Santa Clara County	$3,500 – $5,500	$1,200 – $2,500	$500 – $1,500	$5,200 – $9,500	Santa Clara (including San Jose) has high demand for housing and strict zoning laws, pushing up both building permit costs and planning approval fees.
Ventura County	$2,200 – $4,000	$800 – $1,500	$350 – $1,100	$3,350 – $6,600	Ventura is more affordable compared to Los Angeles and Santa Clara, as it has less demand for urban expansion and fewer utility infrastructure challenges.
Fresno County	$1,500 – $3,000	$500 – $1,200	$250 – $800	$2,250 – $5,000	Fresno is one of the more affordable areas due to its lower land values and fewer utility infrastructure demands. Planning approvals are also less costly.
Long Beach	$3,000 – $4,500	$1,000 – $2,000	$500 – $1,200	$4,500 – $7,700	Long Beach, being part of Los Angeles County, shares similar costs but benefits from having a mix of urban and suburban characteristics.

When Might You Not Need a Permit?

While permits are typically required for all ADU projects, there are exceptions and special situations that might allow for simplified approval processes or even exemptions. Below are some scenarios where you might not need a permit or where the process could be easier:

• Junior ADUs (JADUs):
  If your ADU is classified as a Junior ADU (JADU), meaning it is under 500 sq ft, you may face less intensive review processes. These units are generally considered more manageable and less impactful on the surrounding area, which can lead to a faster, simpler permit approval process.

Permit Type	Average Cost	Region Examples	Notes
Building Permit	$1,500 – $3,000	Los Angeles, San Diego, Riverside County	Smaller units typically cost less, but urban areas like Los Angeles may have higher costs.
Planning Approval	$500 – $1,500	San Francisco, Santa Clara County	JADUs may have less intensive review due to their smaller size, reducing the approval cost.
Utility Connection Permits	$300 – $800	Orange County, Sacramento, Long Beach	Connection fees tend to be lower due to the smaller scale of JADUs. Only basic connections needed.
Impact Fees	$0 – $500	Fresno, Riverside, San Diego	Some areas waive impact fees for JADUs due to their smaller size and minimal environmental impact.
SB 13 Fee Waivers	$0 (Possible Waiver)	Various California cities	SB 13 provides fee waivers for JADUs under 500 sq ft, particularly in smaller counties.

• Pre-approved Ministerial Plans:
  Some cities in California, like Los Angeles and San Diego, have ministerial plans for ADUs that are pre-approved. These plans meet specific criteria set by the city, meaning that if your design follows these guidelines, you won’t have to go through a discretionary review. This speeds up the process, as it eliminates the need for additional approvals or public hearings.

City	Pre-approved Ministerial Plan Availability	Criteria for Pre-approval	Key Requirements	Estimated Costs	Cost Impact
Los Angeles	Yes	– Must follow specific design guidelines.	– Unit size: up to 1,200 sq ft. – Must conform to LADBS design standards.	– Building Permit: $3,000 – $5,000 – Planning Approval: $1,000 – $2,500 – Utility Connection Fees: $500 – $1,500	– Faster approval process. – Lower total permitting costs due to reduced reviews.
San Francisco	Yes	– Must meet zoning and design guidelines. – Unit size: maximum 800 sq ft.	– Requires compliance with San Francisco’s ADU Program. – Must have minimum 10 ft setbacks.	– Building Permit: $4,000 – $6,000 – Planning Approval: $1,500 – $3,000 – Utility Connection Fees: $700 – $2,000	– Reduced planning approval fees. – No public hearings, making the process faster.
San Diego	Yes	– Units under 1,000 sq ft qualify. – Pre-approved plans available for specific types of ADUs.	– Design must align with San Diego’s ADU regulations. – Must meet height and parking requirements.	– Building Permit: $2,500 – $4,500 – Planning Approval: $800 – $2,000 – Utility Connection Fees: $400 – $1,200	– Lower permit fees due to pre-approved plans. – Faster review process.
Santa Clara (San Jose)	Yes	– Must be smaller than 800 sq ft. – Plans must follow state-adopted ADU standards.	– Must be built within existing structures (e.g., garage conversion) or meet required setbacks.	– Building Permit: $3,500 – $5,500 – Planning Approval: $1,200 – $2,500 – Utility Connection Fees: $500 – $1,500	– Reduced fees for pre-approved designs. – Quick approval with no public hearings.
Long Beach	Yes	– Plans must be consistent with Long Beach ADU standards. – Maximum size: 1,000 sq ft.	– Must be a detached or attached ADU. – Must comply with height and design restrictions.	– Building Permit: $3,000 – $4,500 – Planning Approval: $1,000 – $2,000 – Utility Connection Fees: $500 – $1,200	– Lower planning and permit costs. – Reduced review time, speeding up construction.

• SB 13 Fee Waivers for Small ADUs:
  Under California’s SB 13, if your ADU is smaller than 750 sq ft, you may be eligible for fee waivers. This includes waivers for certain permit fees associated with the construction of your ADU. For example, a 500 sq ft ADU may be significantly cheaper to permit than a larger unit. This is a great opportunity to reduce costs and make building an ADU more affordable, especially for smaller units aimed at addressing the affordable housing crisis in California.

In certain cases, you may be able to build or modify your ADU without needing a full permit. For example:

• Detached Structures Smaller than 120 sq ft: Some jurisdictions allow small sheds or tiny homes under a certain size to be built without a permit.
• Temporary Structures: If you’re building a temporary structure, like a prefab unit that’s designed to be removed after a certain period, you might not need a permit.

---

Factors That Affect the ADU Permit Cost

When planning to build an Accessory Dwelling Unit (ADU) in California, understanding the factors that affect the permit costs is essential. These costs can vary widely depending on several key aspects, including your geographic location, the size of your ADU, its type, and other local factors. Let’s dive into these factors to help you budget your project more effectively and avoid unexpected expenses.

Geographic Location Impact on ADU Permit Costs

One of the most significant factors affecting your ADU permit cost is geography. In California, different regions have distinct permit requirements and fees, largely due to local laws, zoning restrictions, and infrastructure needs.

City/Region	Estimated ADU Permit Cost	Why the Cost Differs
Los Angeles	$5,000 – $15,000	High demand, complex zoning, and dense population lead to higher costs for planning and permits.
San Diego	$9,000 – $20,000	Larger urban area, extensive infrastructure needs, and stricter environmental regulations increase permit costs.
Riverside	$3,000 – $8,000	Rural areas with fewer zoning restrictions and lower utility fees result in more affordable permits.
Sacramento	$3,000 – $8,000	Similar to Riverside, Sacramento has lower land costs and fewer urban challenges.
San Francisco	$7,000 – $12,000	Higher fees due to land value, zoning restrictions, and the need for extensive infrastructure.

As shown in the table, the ADU permit cost is significantly higher in urban areas like Los Angeles and San Diego, where demand for housing is greater, and infrastructure challenges add to the costs. On the other hand, areas like Riverside and Sacramento typically offer lower permit fees due to fewer zoning hurdles and less population density.

How ADU Size Affects Permit Fees

The size of your ADU plays a crucial role in determining the permit cost. Generally, the larger the ADU, the higher the permit fees. Here’s how size impacts the cost of permits:

• Under 750 sq ft:
  Permit fees are usually lower for smaller ADUs, especially if they are designed to be affordable housing. Many of these ADUs might even qualify for SB13 fee waivers, which means you could be exempt from some or all of the permit fees.
  • 500 sq ft ADUs: Often have minimal fees, making them an attractive option for homeowners seeking to minimize upfront costs.
• 600 – 800 sq ft:
  As the ADU size increases, you will typically start encountering impact fees (e.g., fees for schools or roads) and higher permit costs. These units will often require more thorough plan reviews and engineering inspections.
• Over 1,000 sq ft:
  Large ADUs (typically those over 1,000 sq ft) generally incur the highest permit costs. At this size, you’ll likely need more detailed planning, including extensive engineering analysis, which will drive up costs significantly.

Prefab vs Custom ADUs: Cost Differences

The type of ADU you choose prefabricated (prefab) or custom-built will also affect the permit cost. Let’s compare the two:

ADU Type	Permit Cost	Why It Affects Costs
Prefab ADUs	Typically lower ($3,000 – $8,000)	Prefabricated units often follow approved designs, which streamline the permit approval process and reduce plan review costs.
Custom-built ADUs	Typically higher ($5,000 – $15,000)	Custom units require more detailed design reviews and engineering assessments, which increase both permit fees and plan review fees.

• Prefab ADUs: These pre-approved plans typically follow standardized designs that have already been reviewed by the local government. This reduces planning approval fees and speeds up the approval process.
• Custom-built ADUs: Custom ADUs involve more detailed planning and design that meet the specific needs of the homeowner. As a result, these units often face higher permit costs because they require more extensive engineering and review.

Other Factors Influencing ADU Permit Costs

Aside from location, size, and type, there are a few other factors that can add to your ADU permit cost. Here are some to keep in mind:

1. Utility Upgrades
   • If your ADU requires upgraded utilities (water, sewer, electricity), you may incur additional connection fees or costs for upgrading existing systems. This can be especially costly in older areas with outdated infrastructure.
2. Impact Fees
   • Impact fees are charges imposed by local governments to fund infrastructure improvements (such as schools, roads, or public services) due to new development. For ADUs, these fees can range from $500 to $5,000, depending on the size of the unit and local regulations. Smaller ADUs (under 750 sq ft) may be exempt from some impact fees, but larger ADUs will likely incur these additional charges.
3. Fire Department Review
   • In high-risk fire zones, especially in California’s wildfire-prone areas, your ADU may require additional fire department reviews, which can increase permit fees. These reviews ensure that the design meets fire safety regulations, including the proper materials, access routes, and defensible space.
4. Local Zoning and Historic District Rules
   • If your property is located in a historic district or has specific zoning requirements, you may face additional costs for zoning reviews and compliance. Certain areas may require special permits for changes to the structure, especially if the ADU is built in or near historic landmarks.

Factor	Estimated Cost	Description	When It Applies
Utility Upgrades	$500 – $5,000	Costs for upgrading existing utilities (water, sewer, electricity). Fees are higher if infrastructure is outdated or in high-demand areas.	– If the ADU requires new utility connections. – Older areas with outdated infrastructure.
Impact Fees	$500 – $5,000	Charges imposed to fund public infrastructure improvements (roads, schools, parks). Fees depend on unit size and local regulations.	– Larger ADUs (over 750 sq ft) generally incur these fees. – Smaller ADUs may be exempt.
Fire Department Review	$200 – $1,500	Additional review in high-risk fire zones. Includes costs for compliance with fire safety regulations (materials, access routes, defensible space).	– California wildfire-prone zones. – Areas with strict fire safety codes.
Local Zoning and Historic Rules	$500 – $2,000	Costs for zoning reviews and compliance, especially in historic districts or areas with strict zoning laws. Special permits may be required.	– Properties in historic districts. – Areas with complex zoning or special designations.

---

How Much Does an ADU Permit Cost in California?

Building an Accessory Dwelling Unit (ADU) in California can be a great way to add extra living space to your property. However, before you start your construction, it’s important to understand the permit costs involved. ADU permit costs vary significantly depending on the location, size, and complexity of the project. In this section, we’ll explore the average costs by region, so you can better plan your budget and avoid surprises.

Average Permit Cost by Region

The cost of obtaining a permit for an ADU is influenced by several factors, but location is one of the most important. Different regions in California have varying permit fees due to differences in local regulations, population density, and the complexity of the required reviews. Below is a breakdown of the average permit cost for an ADU across some of the most popular counties and cities in California:

Location	Estimated Permit Cost	Details
Los Angeles County	$5,000 – $15,000	Costs are higher due to high demand, complex zoning regulations, and urban infrastructure needs. Includes building permits, plan review fees, and some impact fees.
San Diego County	$9,000 – $20,000	Higher fees due to the large urban area, impact fees, and extensive utility connections required. Impact fees can add substantial costs, especially for larger ADUs.
Riverside County	$3,000 – $8,000	More affordable compared to urban areas. Permit fees are generally lower due to less population density and fewer infrastructure challenges. Lower impact fees as well.
San Francisco	$6,000 – $10,000	Similar to Los Angeles, costs are high due to strict zoning and high land value. Includes plan review and impact fees related to urban infrastructure.

Cost Influencers in Different Locations

• Urban vs. Rural Areas:
  Urban areas, like Los Angeles and San Francisco, typically have higher permit costs due to greater demand for housing, complex zoning laws, and the need for extensive infrastructure. In contrast, rural areas like Riverside County tend to have lower costs due to fewer zoning restrictions and less crowded infrastructure systems.
• Size of the ADU:
  The size of your ADU will directly impact the permit cost. Smaller units (under 750 sq ft) tend to have lower fees, especially if they qualify for fee waivers under California’s SB 13 legislation. Larger ADUs (over 1,000 sq ft) generally face higher costs due to more comprehensive reviews and impact fees.
• Local Regulations and Fees:
  Different cities have different local regulations, which can influence the permit costs. For example, San Diego has higher impact fees because of its large urban environment and need for public infrastructure improvements. San Francisco, with its high land value, also has more stringent regulations and higher permit fees.

---

Additional Fees You Might Encounter When Building an ADU

Building an Accessory Dwelling Unit (ADU) in California involves various costs, and it’s crucial to account for the additional fees that may arise beyond the basic permit cost. These extra charges can add up quickly, so it’s important to understand what they are and how they can impact your overall ADU budget. Below, we’ll break down the key additional fees you might encounter when building your ADU.

1. Plan Check Fee

Plan check fees are costs associated with having your architectural drawings and construction plans reviewed by local authorities to ensure compliance with building codes and regulations. These fees are typically charged when submitting plans for review before construction begins.

Type of Fee	Estimated Cost	What’s Included
Plan Check Fee	$500 – $3,000	Cost for reviewing architectural plans to ensure compliance with local building codes, zoning laws, and safety regulations.
Why It Varies	Depends on the complexity of the design and local jurisdiction. More intricate plans lead to higher fees.

Tip: Simple ADU designs will typically incur lower plan check fees compared to complex custom designs. Keep your plans straightforward to reduce this cost!

2. Impact Fees

Impact fees are charged by local governments to fund the infrastructure improvements required to support new development. These improvements might include sewer systems, roads, schools, and other public services. The cost of these fees can vary greatly depending on the size of the ADU and the region.

Type of Fee	Estimated Cost	What’s Included
Impact Fees	$500 – $5,000	Costs for infrastructure improvements (roads, sewer, schools). Based on ADU size and local regulations.
Why It Varies	Larger ADUs incur higher fees due to the increased demand on public services and local infrastructure.

Tip: Smaller ADUs (under 750 sq ft) may be exempt from certain impact fees in some areas, so always check your local ADU regulations for potential savings.

3. Utility Connection Fees

If your ADU needs new connections to water, sewer, or electricity, you’ll face utility connection fees. These fees can include tap-in fees, which are charges for connecting your ADU to the existing utility grid. These fees vary depending on the location of your property, the size of your unit, and the distance to the nearest utility lines.

Type of Fee	Estimated Cost	What’s Included
Utility Connection Fees	$500 – $2,500	Charges for connecting your ADU to local water, sewer, and electric services.
Why It Varies	Depending on how far your ADU is from existing utility lines, the fees can increase due to additional construction or upgrades required.

Tip: Plan your ADU design to be close to existing utility lines to minimize these connection fees. If possible, connect to existing systems already in place on your property.

4. Fire Department Fees

If your ADU requires fire sprinklers or a new address (for larger or detached units), you will likely encounter fire department fees. These are necessary to ensure that your ADU complies with fire safety regulations, especially in areas with high fire risk.

Type of Fee	Estimated Cost	What’s Included
Fire Department Fees	$200 – $1,500	Costs associated with installing fire sprinklers, assigning a new address to the ADU, and meeting fire safety standards.
Why It Varies	Fees can vary depending on local fire department requirements, size of ADU, and whether the unit is in a high-risk fire zone.

Tip: If your ADU is located in a high-risk fire area, consult with your fire department early in the process to understand any additional fire safety requirements that may add to your fees.

Summary of Additional ADU Fees

Fee Type	Estimated Cost Range	What It Covers
Plan Check Fee	$500 – $3,000	Reviewing architectural drawings to ensure code compliance.
Impact Fees	$500 – $5,000	Fees for public infrastructure improvements (roads, schools, sewer, etc.).
Utility Connection Fees	$500 – $2,500	Connecting your ADU to utilities such as water, sewer, and electricity.
Fire Department Fees	$200 – $1,500	Fire safety checks, fire sprinkler installation, and new address assignment.

---

Steps to Get an ADU Permit in California

Building an Accessory Dwelling Unit (ADU) in California is a great way to add living space or rental income to your property, but navigating the permit process can seem daunting. Fortunately, by following a clear set of steps, you can streamline the process and get your ADU permit with fewer surprises. Below, we’ll walk you through the key steps to obtaining an ADU permit in California.

1. Confirm Zoning Compliance and Setbacks

Before you begin your ADU permit application, ensure your property is in a zone that allows ADUs. In California, zoning regulations can vary significantly between cities and counties, so it’s essential to verify compliance with local codes. Key zoning considerations include:

• Zoning Compliance: Check if your property is in a zoned area that permits the construction of an ADU. Some areas may have restrictions based on residential type or lot size.
• Setbacks: Make sure your ADU meets the setback requirements for your specific location. Setbacks determine how far the ADU must be from property lines, streets, and other structures on your lot.

Zoning Requirement	Example Compliance
Minimum Lot Size	In some areas, the lot must be at least 5,000 sq ft for an ADU.
Setback Regulations	ADUs must often be 4-5 feet away from property lines, depending on local regulations.

Tip: If your lot is small or close to existing structures, consider a detached ADU that may have more flexible setback regulations.

2. Gather Required Documents

Once you’ve confirmed zoning compliance, the next step is to gather the necessary documentation for your ADU permit application. The required documents typically include:

• Site Plan: A detailed map showing your property’s boundaries, existing structures, and where the new ADU will be located.
• Floor Plans and Elevations: Drawings that detail the layout of the ADU and how it will look from various perspectives (front, side, and back).
• Structural or Engineering Plans (if needed): Depending on the complexity of your ADU, you may need to submit engineering plans that detail the structure’s design, including foundation, framing, and materials.
• Utility Upgrade Plans: If your ADU requires new or upgraded utility connections (water, sewer, electricity), include plans that show how these utilities will be connected.

3. Submit Application to Local Building Department

After preparing all the necessary documents, the next step is to submit your ADU permit application to your local building department. This is the official process through which you request permission to build the ADU.

• Online vs. In-Person Submission: Many cities offer online submission for ADU permits, which makes the process quicker and more convenient.
• Application Fee: Expect to pay an application fee at the time of submission. This fee varies by location and is typically based on the size and type of the ADU.

Tip: Submit your application early and follow up regularly with the building department to ensure everything is on track.

4. Request Fee Waivers if Under 750 sq ft

Under SB 13, ADUs under 750 square feet may qualify for fee waivers or reductions, including impact fees and permit fees.

• If your ADU falls under this size, be sure to request waivers at the time of your permit application. This can save you a significant amount of money, especially in cities with high impact fees.

ADU Size	Potential Fee Waivers
Under 750 sq ft	Impact fees and permit fees may be waived.

Tip: If your ADU is under 750 sq ft, take advantage of SB 13 and ask for all available waivers to keep costs down.

5. Pay Applicable Fees and Track Review Timeline

After submitting your application, you’ll need to pay any applicable fees. These can include:

• Building Permit Fees
• Plan Review Fees
• Impact Fees (if applicable)

Be sure to track the review timeline to stay updated on your ADU permit status. Depending on the jurisdiction, review times can range from a few weeks to a few months.

6. Pass Inspections and Receive Occupancy Certificate

Once your ADU is constructed, it must pass inspections to ensure it complies with building codes, safety regulations, and zoning requirements. Common inspections include:

• Foundation inspection
• Framing inspection
• Final inspection (before the occupancy certificate is issued)

Once your ADU passes all required inspections, you will receive the occupancy certificate, which officially allows you to move in or rent out the unit.

Inspection Type	When It Occurs	What It Includes
Foundation Inspection	Before pouring concrete	Ensures foundation meets safety and stability requirements.
Framing Inspection	After framing but before drywall is installed	Ensures structural elements meet code requirements.
Final Inspection	After all construction is complete	Verifies overall safety and compliance, leading to the occupancy certificate.

Tip: Schedule inspections in advance and make sure that all required work is completed before the inspector arrives to avoid delays.

Step	Key Action	Estimated Cost Range
1. Confirm Zoning and Setbacks	Check local zoning rules and setbacks before beginning construction.	$0 – $500 (for research or consultations with zoning experts)
2. Gather Documents	Collect site plans, floor plans, and utility plans for your application.	$500 – $2,000 (cost of architectural plans, engineering, and utility plans)
3. Submit Application	Submit your application and pay the application fee.	$200 – $2,500 (varies by city and ADU size)
4. Request Fee Waivers	Ask for fee waivers if your ADU is under 750 sq ft.	$0 (no cost if eligible for SB 13 waivers)
5. Pay Fees and Track Timeline	Pay all applicable fees and monitor your review timeline.	$500 – $10,000 (includes building permit fees, plan review fees, and impact fees)
6. Pass Inspections	Complete required inspections and obtain the occupancy certificate.	$100 – $500 (inspection fees, varies by region)

Total Estimated Costs for the ADU Permit Process:

• Low Estimate: $1,300 (smaller ADU, no major impact fees)
• High Estimate: $15,000 (larger ADU, includes impact fees and full permit costs)

---

What Are the Requirements for an ADU Permit Fee Waiver?

Building an Accessory Dwelling Unit (ADU) in California can be an exciting project, but navigating the associated permit fees can be daunting. Fortunately, California’s SB 13 law has introduced provisions that help reduce the costs of building an ADU by offering permit fee waivers under certain conditions.

If you’re planning to build an ADU, understanding the specific requirements for obtaining a permit fee waiver can save you thousands of dollars—especially on impact fees and school fees.

1. ADU Must Be ≤ 750 sq ft for Impact Fee Waiver

One of the key requirements for an ADU fee waiver is that your ADU must be 750 square feet or less. This size limit makes the ADU eligible for an impact fee waiver, which can significantly reduce the overall cost of building your unit.

Why 750 sq ft?

• Smaller ADUs are considered less impactful on local infrastructure, such as roads, utilities, and public services. The 750 sq ft threshold allows homeowners to build a cost-effective unit without bearing the financial burden of significant infrastructure fees.

ADU Size	Impact Fee Waiver Eligibility
≤ 750 sq ft	Eligible for impact fee waiver (covers roads, utilities, etc.).
> 750 sq ft	May be subject to impact fees depending on location and size.

Tip: If you can design your ADU to be under 750 sq ft, you can take advantage of the SB 13 impact fee waiver, saving money that would otherwise be spent on impact fees. These fees can range from $500 to $5,000, depending on the size and location of your ADU. Designing a smaller unit can not only help with impact fees but may also reduce overall permit costs, making your ADU more affordable to build.

2. School Fee Exemption for ADUs Under 500 sq ft

In addition to impact fee waivers, California also offers an exemption from school fees for ADUs under 500 square feet. This exemption is particularly beneficial for smaller ADUs that are typically designed to provide affordable housing or serve as rental units.

Why is this important?

• School fees are levied to support local school districts and cover the costs of additional students generated by new development. However, for smaller ADUs, it’s believed that the impact on school enrollment is minimal, and therefore the fees can be waived.

ADU Size	School Fee Exemption Eligibility
≤ 500 sq ft	Eligible for school fee exemption.
> 500 sq ft	Likely subject to school fees depending on local policies.

Tip: To reduce your overall ADU permit costs, aim to keep your ADU under 500 sq ft if school fee exemptions are available in your area.

3. Submit Plans that Comply with Local Codes

Even if your ADU meets the size requirements for fee waivers, you’ll need to submit plans that comply with your local building codes. These plans should clearly show the ADU’s size, design, and the necessary utilities.

What is required in your plans?

• Site Plan: Shows the location of the ADU on your property and how it interacts with other structures, including setbacks.
• Floor Plans: Provide detailed layout and dimensions of the ADU.
• Elevation Drawings: Show the height and external appearance of the ADU.
• Structural and Engineering Plans: If required, these plans ensure the ADU meets safety standards.

Required Plan Type	Purpose
Site Plan	Shows the location of the ADU on the property.
Floor Plans	Shows interior layout and dimensions of the ADU.
Elevation Drawings	Shows the external design, height, and structural details.
Structural Plans	Ensures the ADU meets safety and building codes.

Tip: Work with a licensed architect or designer to ensure your ADU plans meet local building codes and clearly display the ADU size. This will streamline the approval process and avoid delays in your permit application.

4. Request Permit Fee Waivers at the Permit Office

Once you’ve confirmed that your ADU meets the size requirements for the impact fee waiver and school fee exemption, the next step is to request the waivers from your local building department.

How to Request the Waiver:

• Ask the Permit Office: When submitting your ADU permit application, specifically request the SB 13 waivers for impact fees (if applicable) and school fees for smaller units.
• Provide Documentation: Ensure that your ADU plans are ready for review and clearly show the ADU size and compliance with local codes.

Tip: Don’t forget to ask your local permit office about any additional waivers available, especially if you’re building in a high-demand area with affordable housing goals. Many cities offer additional reductions in permit fees for affordable ADUs.

ADU Size	Impact Fee Waiver	School Fee Exemption	Required Documents
≤ 750 sq ft	Waived	Not Applicable	Site Plan, Floor Plans, Structural Plans
≤ 500 sq ft	Waived	Waived	Site Plan, Floor Plans, Structural Plans
> 750 sq ft	Not Waived	Possible School Fees Apply	Site Plan, Floor Plans, Structural Plans

---

How Permit Costs Affect Your ADU Project Budget

When building an Accessory Dwelling Unit (ADU) in California, permit costs are an important factor in your overall budget. These costs can range from 5% to 10% of the total cost of the project, depending on various factors like location, ADU size, and design complexity. Understanding and managing these costs early in the process is essential to avoid unexpected expenses that could strain your budget.

Permit Fees Typically Represent 5–10% of Your Total ADU Budget

While it may not seem like a large percentage at first, permit fees can add up quickly as your ADU project progresses. For example, the total ADU construction cost in California can range from $100,000 to $300,000 or more, depending on size and location. If permit fees make up 5–10% of that total cost, you could be looking at anywhere from $5,000 to $30,000 in fees. Here’s how the breakdown might look:

Total ADU Cost	Permit Fees (5-10%)	Estimated Fee Range
$100,000	5% – 10%	$5,000 – $10,000
$200,000	5% – 10%	$10,000 – $20,000
$300,000	5% – 10%	$15,000 – $30,000

Tip: Early in the planning process, estimate your permit costs based on your ADU size and location. This will help you plan better and avoid overestimating or underestimating the impact of these fees on your budget.

Money-Saving Tips for ADU Permit Costs

Managing ADU permit costs efficiently can make a significant difference to your bottom line. Here are some money-saving strategies to reduce the impact of permit fees on your project budget:

Stick to Under 750 sq ft to Avoid Impact Fees

One of the most effective ways to save on permit costs is to design your ADU to be under 750 sq ft. In California, SB 13 offers a waiver for impact fees for ADUs under 750 sq ft. This could save you anywhere from $500 to $5,000 in impact fees.

ADU Size	Impact Fee Waiver Eligibility	Estimated Savings
≤ 750 sq ft	Waived (impact fees)	$500 – $5,000
> 750 sq ft	Impact fees apply	$500 – $5,000

Tip: Keep your ADU under 750 sq ft if possible to maximize your savings on impact fees.

Use Pre-Approved or Prefabricated Plans

Another way to save on permit fees is by using pre-approved or prefabricated ADU plans. Many cities offer pre-approved plans that comply with local building codes and zoning regulations. These plans are designed to streamline the permit approval process, reducing both review fees and overall permit costs.

Type of Plan	Cost Impact	Why It’s Beneficial
Pre-approved Plans	Typically lower fees ($500 – $1,500)	Simplifies plan review, speeds up approval, and lowers fees.
Prefab ADUs	Typically lower fees ($1,000 – $3,000)	Streamlined design with standardized plans reduces complexity.

Tip: Check if your city offers pre-approved plans or if you can use a prefabricated ADU to save time and money on permit processing.

Factor Early for Utility and Impact Fees

Utility and impact fees can be significant, especially if your ADU requires new water, sewer, or electricity connections. These fees can vary widely depending on the location and whether utilities need to be upgraded.

Tip: Factor in these additional fees early in the process. Contact your local utility providers to understand any costs related to utility hookups or upgrades, as these can impact your overall ADU budget.

Request Waivers Clearly in the Application

If your ADU is eligible for SB 13 waivers, such as impact fee waivers for units under 750 sq ft, be sure to request these waivers clearly in your permit application. Many homeowners miss out on potential savings by not explicitly asking for these fee reductions.

Waiver Type	Eligibility	How to Request
Impact Fee Waiver	ADUs under 750 sq ft	Request in your permit application.
School Fee Exemption	ADUs under 500 sq ft	Explicitly request in the application.

Tip: When submitting your permit application, be sure to ask for any fee waivers available, particularly for impact fees and school fees, as these can significantly reduce your costs.

Strategy	Potential Savings
Design ADU to be ≤ 750 sq ft	$500 – $5,000 (impact fees)
Use Pre-approved or Prefab Plans	$500 – $3,000 (plan review fees)
Factor in Utility and Impact Fees	Varies by location and utility requirements
Request Fee Waivers	Significant savings on impact fees and school fees

---

What Cities Offer ADU Permit Fee Waivers?

In California, the process of building an Accessory Dwelling Unit (ADU) can be costly, but fortunately, many cities offer permit fee waivers or fee reductions to encourage ADU construction. These waivers can help significantly lower the cost of building an ADU by reducing impact fees, permit fees, and other related costs. Below, we highlight cities with supportive policies that make it easier and more affordable to build an ADU.

Los Angeles County / Altadena: Automatic SB13 Waivers for ADUs Under 750 sq ft

Los Angeles County and Altadena offer automatic SB 13 waivers for ADUs under 750 square feet. This means that if your ADU is under 750 sq ft, you are automatically eligible for impact fee waivers, saving you a significant amount on fees that would otherwise be charged for infrastructure improvements like roads, schools, and utilities.

City/Area	Waiver Details	Fee Waived
Los Angeles County	Automatic SB13 waivers for ADUs under 750 sq ft	Impact Fees (for infrastructure)
Altadena	Same as Los Angeles County for under 750 sq ft ADUs	Impact Fees and permit fees

Tip: If you’re planning to build a smaller ADU, try to keep it under 750 sq ft to take advantage of the automatic SB 13 waivers and save on impact fees.

San Diego: Exemptions Under SB13; Previous Local Waiver Programs (Ended in 2023)

San Diego is another city that has historically supported ADU construction through SB13 exemptions, including waivers for smaller ADUs. While previous local waiver programs were in place (which ended in 2023), SB 13 continues to offer waivers for impact fees for ADUs under 750 sq ft. However, the specifics of these waivers have been modified, so it’s important to stay up to date on current regulations.

City	Waiver Details	Fee Waived
San Diego	SB13 exemptions for ADUs under 750 sq ft, previous local waivers ended in 2023.	Impact Fees (only for smaller ADUs)

Tip: While San Diego no longer offers its previous local waivers, you can still benefit from SB 13 exemptions if your ADU is under 750 sq ft. Stay in touch with your local building department for any new fee reduction programs.

Sacramento: Actively Promotes ADUs Through Fee Waivers and Free Plan Libraries

Sacramento has actively promoted ADU construction by offering a variety of fee waivers and support programs. This includes waivers for impact fees for smaller ADUs and access to free ADU plan libraries that reduce design costs. By offering these programs, Sacramento aims to make ADU construction more affordable and accessible.

City	Waiver Details	Fee Waived
Sacramento	Promotes ADUs with fee waivers, including impact fees and access to free ADU plan libraries.	Impact Fees, Design Plan Costs

Tip: Take advantage of Sacramento’s free ADU plan libraries, which provide pre-approved plans that can lower your design fees and help streamline your permit application process.

Other Cities Offering ADU Permit Fee Support

In addition to Los Angeles, San Diego, and Sacramento, other cities across California offer varying levels of ADU permit fee waivers or reductions, including:

• San Jose: Offers reduced permit fees and impact fee waivers for smaller ADUs.
• Oakland: Offers waivers for impact fees and reduced review fees for ADUs that meet certain affordable housing criteria.
• Fresno: Provides affordable permitting options with reduced fees for smaller ADUs.

Tip: Always check with your local city or county planning department to find out what waivers and discounts are available for ADUs in your area. Some cities may have specific programs that can help you save.

City/Area	Waiver Details	Eligible ADU Size	Fee Waived
Los Angeles County	Automatic SB13 waivers for ADUs under 750 sq ft	Under 750 sq ft	Impact Fees and permit fees
Altadena	Same as Los Angeles County	Under 750 sq ft	Impact Fees and permit fees
San Diego	SB13 exemptions for ADUs under 750 sq ft, local waivers ended in 2023	Under 750 sq ft	Impact Fees
Sacramento	Promotes ADUs with fee waivers and free plan libraries	Varies	Impact Fees and design plan costs
San Jose	Reduced permit fees and impact fee waivers	Varies	Permit Fees and impact fees
Oakland	Impact fee waivers and reduced review fees	Varies	Impact Fees and review fees
Fresno	Offers affordable permitting options	Varies	Permit Fees

---

Frequently Asked Questions About ADU Permit Cost

What are the typical costs for obtaining an ADU permit in California?

The typical costs for obtaining an ADU permit in California can vary based on location, size, and complexity of the project. On average, permit fees range from $3,000 to $15,000. This usually includes the building permit, planning approval, and utility connection fees (for water, electricity, and sewer connections). More urban areas like Los Angeles and San Francisco tend to have higher fees due to stricter zoning and infrastructure requirements, while rural areas like Riverside and Sacramento may have more affordable permit costs.

How much do impact fees add to the ADU permit cost in California?

Impact fees are charges added to the ADU permit cost to help fund local infrastructure improvements (like roads, schools, parks). The amount can range from $500 to $5,000, depending on the size of the ADU and the local jurisdiction. Smaller ADUs (under 750 sq ft) may qualify for waivers for these fees, particularly under California’s SB13 law. Larger units, however, often incur these additional costs, particularly in high-demand urban areas.

How much does an ADU permit cost in Los Angeles?

In Los Angeles, ADU permit costs typically range from $5,000 to $15,000. This includes a building permit, planning approval, and utility connection fees. The cost is on the higher end due to dense population, high demand for housing, and complex zoning regulations. Utility connection fees can also be significant due to the city’s extensive infrastructure.

What is the ADU permit cost in San Francisco?

The cost of obtaining an ADU permit in San Francisco is generally between $6,000 and $11,000. The high cost is due to strict zoning laws, high land value, and the need for extensive infrastructure. Permits for ADUs often include building permits, planning approvals, and utility connection fees, with additional impact fees in certain cases.

How much are ADU permits in San Diego, California?

In San Diego, ADU permit costs range from $3,700 to $7,700. This price range includes building permits, planning approval fees, and utility connection fees. The costs are relatively lower compared to cities like Los Angeles and San Francisco due to less stringent zoning regulations and lower utility fees.

What is the ADU permit cost in Riverside County?

In Riverside County, permit costs for an ADU typically range from $2,800 to $6,000. Riverside is more affordable because it is less densely populated compared to urban areas like Los Angeles and San Francisco. The lower demand for utilities and fewer zoning restrictions contribute to these lower costs.

How much do permits cost for an ADU in Orange County?

Orange County ADU permit costs typically range from $4,600 to $9,500. These costs are similar to those in Los Angeles due to urban sprawl, higher demand for utilities, and stricter zoning regulations. The fees include the building permit, planning approval, and utility connection fees.

What is the cost for an ADU permit in Sacramento?

In Sacramento, the cost for an ADU permit generally ranges from $3,850 to $6,800. Sacramento’s lower costs are due to fewer zoning hurdles and less infrastructure demand compared to coastal cities. However, costs can increase if utilities need significant upgrades.

How much is the ADU permit cost in Ventura County?

The ADU permit cost in Ventura County typically ranges from $3,350 to $6,600. Ventura is more affordable than cities like Los Angeles or Santa Clara, as it faces less demand for urban expansion and fewer challenges with utility infrastructure. This leads to lower permit fees and impact fees.

Why are ADU permit costs higher in Los Angeles compared to Riverside?

ADU permit costs in Los Angeles are higher than in Riverside due to several factors:

• Urban density: Los Angeles has a higher population, leading to more demand for infrastructure.
• Stricter zoning laws: Los Angeles has more complex zoning regulations and restrictions.
• Higher utility fees: Due to its extensive infrastructure, utility connection fees in Los Angeles are more expensive than in Riverside, where infrastructure is less developed.
• Higher land value: The cost of land in urban areas like Los Angeles is much higher, contributing to overall permit costs.

What permits are included in the ADU permit cost in California?

The typical ADU permit cost in California includes several types of permits:

• Building Permit: Ensures the ADU complies with local building codes and is structurally sound.
• Planning Approval: Ensures the ADU meets local zoning regulations, including setbacks, height restrictions, and land use.
• Utility Connection Permits: Required if the ADU needs connections for water, electricity, sewer, or gas.
• Impact Fees: These fees are for infrastructure improvements (e.g., roads, schools, parks) and are typically added based on the size of the ADU.

Understanding each of these components will help you better estimate your total permit cost when building an ADU in California.

---

Conclusion

Building an Accessory Dwelling Unit (ADU) in California is an exciting opportunity to expand your living space or generate rental income. However, understanding the permit costs involved is essential to avoid unexpected financial surprises. Whether you’re in Los Angeles, San Diego, or Sacramento, ADU permit fees can vary significantly based on your location, the size of your unit, and the complexity of the project.

But here’s the good news: permit fee waivers under SB 13 are designed to make the ADU process more affordable. By taking advantage of these fee reductions such as impact fee waivers for units under 750 sq ft you can save thousands of dollars on your ADU project. Cities like Los Angeles, San Diego, and Sacramento actively support ADU construction with these waivers, and other areas are following suit by offering affordable design plans and reduced permit fees.