Common Mistakes When Applying for an ADU Permit

Applying for an Accessory Dwelling Unit (ADU) permit can feel overwhelming, especially for first-time applicants. One of the most important questions to ask early on is: What mistakes can delay or derail the ADU permit approval?

Knowing these pitfalls in advance saves time, money, and frustration — and using resources like a preapproved ADU plan or permit ready ADU plans can make a major difference.

Mistake 1: Submitting Incomplete Applications

Cities require a full package including:

• Site plan

• ADU blue print

• Floor plan

• Energy compliance reports

• Structural details

Missing any document will almost guarantee corrections and delays.

Mistake 2: Ignoring Local Zoning Rules

Every city has different:

• Setback requirements

• Parking rules

• Size limits for ADUs

Reviewing zoning codes before submitting your ADU permit application ensures the design matches local regulations.

Mistake 3: Choosing Overly Complex Designs

Custom, multi-story, or unusually shaped ADUs take longer to approve and build.Using a preapproved ADU plan simplifies the process and keeps reviews short.

Mistake 4: Missing Fire Safety Features

Fire separation between units, smoke alarms, and egress windows are essential parts of any ADU permit plan.Overlooking them leads to costly redesigns.

Mistake 5: Underestimating Utility Requirements

ADUs often require:

• New sewer connections

• Water upgrades

• Electrical service updates

Planning utility connections in your permit ready ADU plans prevents last-minute surprises.

Mistake 6: Poor Quality Drawings

Vague or incomplete drawings cause confusion. A clear, detailed ADU blue print that follows professional drafting standards can significantly speed up approvals.

Mistake 7: Not Budgeting for Permit Fees

Typical fees include:

• Plan check fees

• Building permit fees

• Utility connection fees

• School district fees (sometimes)

Knowing these costs up front helps avoid financial delays.

Mistake 8: No Communication With Neighbors

While not always legally required, keeping neighbors informed about your ADU project prevents complaints that might bring extra scrutiny from city officials.

Real-World Example

A homeowner in Los Angeles submitted an ADU application with missing energy documentation and an incomplete site plan.Result:

• Two correction rounds

• Four-month delay

• Additional architect fees to fix errors

In contrast, another homeowner in San Diego used a permit ready ADU plan and complete package.Their ADU permit was approved in just 7 weeks.

Final Thoughts

Avoiding common mistakes when applying for an ADU permit is crucial to staying on schedule and avoiding unnecessary expenses. At ADUnest, we specialize in preparing detailed ADU blueprints, helping homeowners select the best preapproved ADU plans, and creating permit ready ADU plans that move faster through approval.If you have questions about the ADU permit process, required drawings, or next steps, feel free to leave a comment below.The ADUnest team will answer as soon as possible to help you succeed!