If you’ve been thinking about adding an accessory dwelling unit to your property, California’s ADU rules are continuing to move in a homeowner-friendly direction. Changes taking effect in 2026 clarify how ADU size is measured, create firmer expectations around application review, and build on earlier laws that removed some of the barriers that once made ADUs harder to pursue.
For homeowners in Davis and Sacramento, those changes may make an ADU more feasible. But the law is only one piece of the project. Your lot, existing home, utilities, privacy, access, long-term plans, and the needs of the person who’ll live in the space all matter.
At MAK Design + Build, we approach ADUs the same way we approach any meaningful change to your home: by first understanding what you need the space to do. An ADU for an aging parent may need to function differently from one designed for adult children, frequent guests, a caregiver, or future rental flexibility.
Here’s what the California ADU law changes mean in 2026 and what you should know if you’re considering an ADU in Davis or the Sacramento area.
How Quickly Can Your ADU Application Be Approved in Sacramento?
What Sacramento County ADU Requirements and Fees Should You Know About?
California has repeatedly changed its ADU laws over the past several years with the goal of reducing barriers to adding housing. The California Department of Housing and Community Development’s March 2026 ADU Handbook incorporates legislation that took effect January 1, 2026.
Some of the changes and existing rules that matter most to you in 2026 include:
These changes can make the process clearer, but they don’t make every ADU automatic. Local standards, site conditions, utilities, building codes, and the type of ADU you’re proposing must still be considered.
If you’re starting to explore an ADU, our work with ADUs and flexible living spaces can help you think beyond what’s legally possible to what will actually work well on your property.
One of the notable new ADU laws in California for 2026 comes from SB 543, which clarifies how floor area is measured for certain ADU provisions.
Under the updated law, relevant ADU floor-area calculations focus on interior livable space. That distinction matters because the usable area inside an ADU isn’t necessarily the same as its entire exterior footprint. The change also affects how certain size-based fee rules are applied.
For you, the larger question is what those square feet need to accomplish.
A thoughtfully designed 700-square-foot ADU can feel generous when flow is simple, storage has a purpose, natural light reaches the right places, and rooms don’t compete for space. A larger unit can still feel awkward if the layout wasn’t designed around how someone will actually live there.
Before trying to maximize the ADU size limit in California, consider the people the space needs to accommodate.
You might ask:
These are design questions, not just zoning questions. And they’re often more important to the success of the finished ADU than adding every square foot the property will allow.
In most cases, no. California permanently removed the general owner-occupancy requirement for ADUs through AB 976. That law took effect before 2026, but it remains an important part of the California ADU laws homeowners are working under today.
That creates more long-term flexibility.
You might build an ADU today so a parent can live nearby, then use it differently years from now. It might eventually accommodate an adult child, a caregiver, extended family, or a tenant. Your own plans may change too.
There is an important distinction for Junior Accessory Dwelling Units, or JADUs, which have separate requirements under state law. If you’re considering a JADU rather than a conventional ADU, you’ll want to confirm which rules apply to your property.
That flexibility is one reason an ADU is often less about “adding a second unit” and more about preparing your home for the next chapter of your life. It also fits the way we’ve approached remodeling for more than 20 years. You can read more about MAK’s story and the thinking behind our work.
One of the biggest sources of confusion around ADU permitting in Sacramento and elsewhere in California is the difference between a permit review deadline and the timeline for the entire project. They aren’t the same thing.
For a qualifying ADU application that’s complete, a local agency generally has 60 days to approve or deny the application. California’s 2026 changes also require the permitting agency to determine within 15 business days whether your application is complete. If it isn’t, the agency must identify the missing information.
That gives homeowners a clearer framework for the government review portion of the process.
It doesn’t mean you can go from “We should build an ADU” to breaking ground in 60 days.
Before an application is ready for review, there may be site evaluation, design development, engineering, utility planning, construction drawings, selections, and other coordination. After approval, construction still has to happen.
For a fuller picture, our guide to how long a design-build remodel takes in Sacramento and Davis looks at the entire process. MAK typically sees ADU projects take roughly 10 to 18+ months from design through completion, depending on permitting, site work, utilities, scope, and construction complexity.
The state's 60-day rule is useful, but it represents one part of a much larger process.
California law creates an accelerated review process for certain detached ADUs that use a plan already familiar to the local jurisdiction. For a complete qualifying application, the local agency generally has 30 days to approve or deny it when the detached ADU uses either a plan pre-approved by that agency during the current building-code cycle or a plan identical to one the agency previously approved during that cycle.
That can make pre-approved ADU plans appealing if speed and simplicity are priorities.
But “pre-approved plan” doesn’t mean “pre-approved property.”
Your lot still matters. So do setbacks, utilities, access, drainage, existing structures, trees, site work, and other conditions that can affect whether and how a particular ADU fits.
A standard plan may work beautifully for some homeowners. For others, it may solve the permitting question without solving the design question.
Consider whether the plan:
Saving time in plan review can be valuable. But you’ll live with the design much longer than you’ll live with the permit application.
If you’re researching ADU Sacramento County requirements, start by confirming which local agency handles permits for your property.
A Sacramento mailing address doesn’t necessarily mean your home is within Sacramento city limits. If your property is in the City of Sacramento, you’ll follow the City’s ADU permitting process. If it’s in an unincorporated part of Sacramento County, you’ll generally apply through Sacramento County instead.
That distinction can affect the standards, procedures, fees, and resources that apply to your project.
ADU impact fees are charges that help offset the added demand a new dwelling unit may place on local infrastructure and public services, such as roads, parks, schools, or other community facilities. They’re different from permit or plan-review fees, which cover the cost of reviewing and approving your project.
California law limits certain impact fees for smaller ADUs. Sacramento County’s 2026 Transportation Mitigation Fee schedule, for example, exempts ADUs under 750 square feet from that particular fee. Larger ADUs are charged proportionally based on the ADU’s floor area compared with the primary residence.
Other Sacramento County development-fee programs also include ADU-specific exemptions or reduced calculations. For example, the County’s 2026 library facilities fee schedule exempts qualifying smaller ADUs and applies proportional calculations to others.
That’s why it can be misleading to quote a single “Sacramento ADU permit fee.” The final amount depends on the jurisdiction, the size of the unit and property, utilities, applicable districts, and the specific permits involved.
And permit fees are only one part of the financial picture. If you’re trying to understand what an ADU project may require overall, our Sacramento and Davis remodeling cost guide includes current planning ranges for ADUs and other residential remodeling projects.
For Davis homeowners, statewide ADU law creates the framework, but the City of Davis still plays an important role in reviewing and permitting individual projects.
The City currently identifies several ADU pathways, including certain “State Exempt” ADUs that may qualify for building-permit-only processing, ministerial ADUs, and projects that require additional review depending on their design and circumstances.
Davis also offers free pre-designed ADU plans in three sizes:
Each size is available in multiple architectural styles. Because the plans have already been reviewed by the City, Davis says they can provide a quicker review process and reduced plan-check fees, although individual properties still require the applicable site and permit review.
That can be a useful option. Still, established Davis neighborhoods often come with their own design puzzle.
Where does the ADU sit in relation to mature trees? Will its windows face your patio or a neighbor’s bedroom? How will someone reach the unit without walking through the middle of your private outdoor space? What happens to shade in August? Does the structure feel like it belongs with the existing house?
Those aren't questions a statewide law can answer for you.
California establishes statewide protections for ADU size, but the exact size you can build depends on the type of ADU, your property, and applicable local standards. SB 543 also clarified the use of interior livable space for certain ADU floor-area provisions beginning in 2026. Before assuming the maximum size is the right size, it's worth studying what your lot and intended use actually need.
Sacramento County ADU requirements depend on whether your property is in unincorporated Sacramento County or within an incorporated city such as Sacramento. State law establishes many baseline protections, while local agencies handle site-specific zoning, building, utility, and permit requirements. Confirming jurisdiction is one of the first steps you should take.
A local agency generally has 60 days to approve or deny a complete qualifying ADU application. In 2026, agencies also have 15 business days to determine whether an application is complete. Certain qualifying detached ADUs using pre-approved or identical previously approved plans may be eligible for a 30-day review period. Those deadlines cover agency review, not the entire design and construction process.
There isn't one universal Sacramento ADU permit price. Fees can vary with jurisdiction, unit size, project valuation, utilities, applicable districts, and site conditions. Some impact fees are exempt or reduced for qualifying smaller ADUs. Sacramento County's current transportation fee schedule, for example, exempts ADUs under 750 square feet from that specific fee.
Generally, no. AB 976 permanently removed California's general owner-occupancy requirement for ADUs. Junior ADUs have separate requirements, so you should confirm the rules if you're considering a JADU rather than a standard accessory dwelling unit.
A law can tell you what you’re allowed to build. It can’t tell you what you should build.
Before choosing a footprint or falling in love with a floor plan, think about the people first.
Ask yourself:
An ADU may be small compared with a primary residence, but it contains many of the same systems as a house: foundation, framing, electrical, plumbing, mechanical systems, a kitchen, a bathroom, and utilities.
That means design decisions quickly become construction decisions.
At MAK, our design-build process keeps those conversations together from the beginning. Our in-house designers and builders collaborate as the project develops, so aesthetics, feasibility, budget, and construction details don't have to live in separate worlds.
It’s a process built around four simple ideas: We Meet, We Design, We Build, We Celebrate.
We start by listening. Then we look closely at your home and property, work through the design with you, develop permit-ready plans and pricing, and carry that thinking into construction.
If you want to see how that attention to proportion, light, materials, function, and individual homes translates into finished spaces, take a look through our remodeling portfolio.
California’s 2026 ADU rules can make some parts of the process clearer and more flexible. But the questions that create a good ADU are still deeply personal.
Who are you creating the space for? What would make it comfortable? How much independence should it provide? How should it sit beside the home you've already built a life in?
At MAK Design + Build, that’s where we begin.
We don't start by squeezing a generic structure into the available corner of your lot. We start by listening to what you want the space to make possible, then bring design and construction together to create something thoughtful, practical, and specific to your property.
That approach has shaped who we are since MAK began in Davis more than 20 years ago. Today, we work with homeowners throughout Davis, Sacramento, Woodland, Winters, and nearby communities, generally within about 45 minutes of our Downtown Davis office.
If an ADU could help your home support the next stage of your life, contact us to start a conversation. We'll listen to what you're hoping to accomplish and help you understand what your property could become.