What to Know About ADU Inspections and Approvals
ADU construction in California follows clear safety and building standards to ensure every living space meets state and local requirements. While the inspection process may seem intimidating at first, understanding what to expect makes it much easier to navigate. At MF ADU, we guide homeowners through each step, making sure your ADU meets all regulations before, during, and after construction.
Why ADU Inspections Matter
Inspections protect homeowners by ensuring the ADU is safe, structurally sound, energy-efficient, and fully compliant with California building codes. These checkpoints also help prevent costly repairs later by catching issues early in the construction process.
Types of Inspections Your ADU Will Undergo
1. Foundation and Site Work Inspection
Before the ADU is delivered or framed, inspectors verify that the foundation and utilities meet approved plans and local standards.
2. Rough Construction Inspection
If building on-site, this includes checking framing, plumbing, and electrical systems before walls are closed. For prefabricated ADUs, much of this step is already completed in a factory and inspected off-site.
3. Energy and Safety Inspections
California requires strict compliance with energy efficiency regulations, including insulation, ventilation, and heating systems. Inspectors verify these elements before final approval.
4. Final Inspection
Once everything is installed and completed, a final inspection confirms that the ADU is fully safe and ready for occupancy. After passing, you receive the certificate of occupancy.
How Prefabricated ADUs Simplify Inspections
A major advantage of prefabricated ADUs is that many inspections happen inside the factory, where construction occurs in a controlled environment. This streamlines the approval process by:
Reducing the number of on-site inspections
Ensuring higher precision and quality control
Eliminating weather-related delays
At MF ADU, our prefabricated units undergo multiple internal inspections before they ever leave the factory—saving time and ensuring consistent quality.
Did you know?
Did you know? Prefabricated ADUs often pass final inspections faster because so much of the construction is pre-approved and certified before arriving on-site.
Smooth, Stress-Free Approvals with MF ADU
Inspections and approvals are essential—but they don’t have to be stressful. At MF ADU, we handle coordination with city inspectors, ensure compliance at every stage, and keep you informed throughout the process. With our streamlined approach, your ADU reaches final approval as quickly and smoothly as possible.
Learn more about our efficient process by exploring our prefabricated ADU models.
Frequently Asked Questions
Do all ADUs require inspections?
Yes. Every ADU must pass required inspections to meet California building and safety standards.
How long do inspections usually take?
Most inspections are completed within a day, though scheduling depends on your local city department.
Do prefabricated ADUs reduce the number of inspections?
Yes. Many inspections happen during factory construction, making on-site reviews faster and simpler.
What happens if something fails inspection?
We quickly address any issues and schedule a re-inspection to keep the project moving.
Who schedules the inspections?
MF ADU handles all scheduling, communication, and coordination with local inspectors.