What to Do When Your ADU Permit Application Is Rejected

A Rejected ADU Permit Is Not the End

You spent weeks (maybe months) researching ADU options, hired a designer, assembled your plans, and submitted your application to the city. Then the letter arrives: your permit has been denied. It is a frustrating setback, and it can feel like the entire project is dead in the water.

But here is the reality: most ADU permit rejections are based on specific, correctable issues. California law gives homeowners strong protections when it comes to ADU approvals, and cities are legally required to tell you exactly why your application was denied. With the right approach, you can revise your plans and resubmit, often within a few weeks.

This guide explains why ADU permits get rejected, what your rights are under California law, how to fix and resubmit your application, and when to call in professional help.

Why ADU Permits Get Rejected

Understanding the reason behind your denial is the first step toward resolving it. Here are the most common causes.

Setback Violations

Every city has rules about how close a structure can be to property lines. For ADUs, California state law sets the maximum allowable setback at four feet for the rear and sides. However, some cities impose additional requirements depending on the zone or lot configuration. If your proposed ADU footprint encroaches into the required setback area, the permit will be denied.

Common setback issues include:

• Eaves, overhangs, or roof projections extending into the setback zone
• Incorrect property line surveys leading to miscalculated distances
• Confusion between the city’s local setback rules and the state’s four-foot maximum

Incomplete or Insufficient Plans

Permit applications require a specific set of architectural drawings and supporting documents. Missing even one item can trigger a rejection. Common omissions include:

• Floor plans without adequate dimensions or room labels
• Missing structural engineering calculations
• No Title 24 energy compliance report
• Absent or incomplete site plans showing the ADU in relation to the main house, property lines, and easements
• Missing grading and drainage plans

Utility Conflicts

Your proposed ADU may create conflicts with existing utility infrastructure. Sewer capacity is a common issue in older Bay Area neighborhoods where the municipal sewer system is already near capacity. Water supply, electrical service, and gas connections also require adequate capacity.

Some cities require a sewer capacity study or a will-serve letter from the local utility before they will approve an ADU permit. If these documents are missing or if the utility identifies a conflict, the permit gets held up or denied.

Fire Access and Egress Issues

Fire departments review ADU applications for emergency access. If your ADU is located behind the main house on a narrow lot, the fire department may flag access concerns. Egress requirements for bedroom windows (minimum size and height specifications) are another common failure point.

Exceeding Allowable Floor Area

California law allows detached ADUs up to 1,200 square feet regardless of lot size. But if your ADU is attached to the main house, the combined floor area may trigger floor-area-ratio (FAR) limits in your city’s zoning code. Some homeowners discover this only after submitting plans.

Building codes and permit requirements change. Verify current requirements with your local building department before starting any project.

Your Rights Under California ADU Law

California has passed a series of laws since 2017 that significantly limit a city’s ability to deny ADU permits. Understanding these protections is essential when your application is rejected.

Ministerial Approval

Under Government Code Section 65852.2, ADU applications must be processed ministerially. This means the city cannot hold a public hearing, cannot apply subjective design standards, and cannot deny your project because a neighbor objects. If your plans comply with the objective development standards, the city is legally obligated to approve them.

The 60-Day Rule

Once you submit a complete application, the city has 60 days to approve or deny it. SB 543, effective January 1, 2026, adds a 15-business-day window during which the city must notify you if your application is incomplete. This prevents the common tactic of letting applications sit without action.

Limits on Local Restrictions

Cities cannot impose minimum lot sizes for ADUs, cannot require owner-occupancy for standard ADUs (per AB 976), and cannot require replacement parking when you convert a garage. If a city denies your permit based on any of these prohibited restrictions, the denial is unlawful.

HCD Enforcement

The California Department of Housing and Community Development (HCD) has authority to review and enforce local compliance with state ADU law. If you believe a city is applying unlawful restrictions, you can file a complaint with HCD. They will investigate and can compel the city to approve compliant applications.

How to Respond to a Rejection

Step 1: Get the Written Denial

Request the written denial if you have not already received it. The letter should cite the specific code sections your application violates. These citations are your roadmap for corrections.

Step 2: Review Each Cited Issue

Go through each reason for denial and categorize it:

• Documentation gaps: Missing reports, calculations, or plan sheets. These are typically the easiest to fix.
• Design conflicts: Setback violations, height exceedances, or FAR issues. These may require plan revisions.
• Utility or infrastructure issues: Sewer capacity, water supply, or electrical service problems. These may require coordination with utility providers.
• Unlawful restrictions: Requirements that violate state ADU law. These should be challenged, not accommodated.

Step 3: Decide Between Revision and Appeal

If the denial is based on legitimate code issues, revise your plans and resubmit. This is almost always faster and less adversarial than an appeal.

If the denial is based on restrictions you believe violate state law, consider filing a formal appeal with the city. You can also contact HCD simultaneously. Many cities reverse denials quickly once HCD gets involved.

Step 4: Revise and Resubmit

Work with your architect or design-build team to address each cited deficiency. Make sure the revised submittal includes a cover letter that references the original denial and explains how each issue has been resolved. This helps the plan checker process your resubmittal efficiently.

Step 5: Track Your Timeline

Once you resubmit a complete application, the 60-day clock resets. Keep records of your submission date and follow up if you do not receive a response within the statutory window.

How to Prevent Rejection in the First Place

The best way to handle a permit rejection is to avoid it entirely. Here is how experienced ADU builders do it.

Commission a Survey Early

A licensed land survey eliminates guesswork about property lines and setback distances. This single step prevents the most common rejection reason.

Get a Pre-Application Meeting

Many Bay Area cities offer pre-application consultations where a planner reviews your concept before you submit formal plans. This is a free opportunity to identify potential issues. Take advantage of it.

Include All Required Documentation

Create a checklist of every document your city requires. Common items include architectural plans, structural calculations, Title 24 energy report, soils report (if required), sewer capacity study, and utility will-serve letters. Missing documents are the most preventable cause of rejection.

Work with Someone Who Knows the Local Process

Permit requirements and plan check procedures vary significantly between Bay Area cities. What works in San Jose may not be sufficient for Los Altos or Palo Alto. An experienced local firm knows each city’s specific requirements, common plan checker preferences, and typical turnaround times.

When to Call a Professional

If your ADU permit has been rejected, consider bringing in professional help in these situations:

• Your plans were drafted without an architect or engineer. Professionally prepared plans are far less likely to be rejected and are faster to revise.
• The denial cites structural or engineering issues. These require licensed professional involvement to resolve.
• You believe the city is applying unlawful restrictions. An experienced ADU builder or a land use attorney can advise you on your rights and the most effective response.
• You have already been rejected once and want to avoid a second denial. A design-build firm that handles permitting regularly can review your plans with fresh eyes and catch issues before resubmission.

Why Design-Build Firms Handle ADU Permitting Better

When you work with a design-build firm like Custom Home Design and Build, the same team that designs your ADU also manages the permit application. This integration eliminates the communication gaps that cause many rejections.

A design-build team knows the specific requirements of each Bay Area jurisdiction. They prepare complete submittal packages the first time, anticipate common plan check comments, and maintain relationships with local planning departments. If a correction is needed, the same architect and engineer who created the plans handle the revision immediately, without the delays that come from coordinating between separate firms.

This approach does not guarantee approval (no one can promise that), but it dramatically reduces the likelihood of rejection and shortens the timeline when corrections are needed.

Get Your ADU Permit Right the First Time

A rejected ADU permit is a setback, not a dead end. Most denials are based on specific, fixable issues, and California law gives you strong protections against unreasonable city restrictions. Whether you revise and resubmit on your own or bring in a design-build team to manage the process, the path forward is usually clear once you understand the reason for denial.

If you are planning an ADU in the Bay Area and want to avoid permit complications, contact Custom Home Design and Build to discuss your project. We handle ADU design and permitting across the Bay Area and can assess your lot’s potential before you invest in plans.