Accessory Dwelling Unit Timeline How Long Does a Prefab ADU Take to Build?

At Okopod, our prefab ADUs are factory-built in Anaheim, California, allowing us to control quality, reduce delays, and deliver faster installations across Southern California.

This guide explains the typical prefab ADU timeline, from design to installation, and what you can expect when building with Okopod.

How Long Does a Prefab Accessory Dwelling Unit Take?

On average, a prefabricated ADU takes 3 to 9 months from initial design to final installation. In some cases, it can be faster depending on permitting and site conditions.

For Okopod projects, the timeline typically breaks down into three clear stages:

1. Design and permitting

2. Factory construction in Anaheim

3. Delivery and installation on site

Stage 1: Design and Permitting (5-24 Weeks)

The first phase focuses on defining the design and securing approvals.

Design Development (1-2 Weeks)

You work closely with the Okopod design team to:

– Confirm ADU size and layout

– Select finishes and materials

– Finalize utility requirements

Prepare permit-ready drawings

Because Okopod uses a modular system, designs are optimized early, which helps avoid redesign delays later.

Permitting (4-24 Weeks)

In California, ADUs require building permits. State law requires local agencies to:

– Review applications for completeness within 15 days

– Approve or deny permits within 60 days

Actual timelines vary by city, but having a standardized prefab design often helps move approvals faster.

Stage 2: Site Preparation

While the ADU is being built in the Anaheim factory, site preparation happens at the same time, including:

– Foundation or pad installation

– Utility trenching

– Electrical, water, and sewer preparation

Because this work runs in parallel with factory construction, it does not extend the overall timeline.

Stage 2: Factory Construction in Anaheim, CA (5 Weeks)

Once permits are approved, your ADU moves into factory production at Okopod’s Anaheim facility.

This is where prefab construction offers the biggest time advantage.

Why Factory Construction Is Faster

– No weather delays

– Consistent working conditions

– Multiple trades working in parallel

– Precision-built components

Walls, roofs, insulation, windows, interiors, and services are all completed off-site with strict quality control.

While site-built ADUs can take 3 to 9 months just for construction, Okopod ADUs are built in the factory in as little as 8 to 12 weeks.

Stage 3: Delivery and Installation (2-4 Weeks includes Site Preparation)

Once factory construction is complete, the ADU is delivered to your property.

Installation Methods

Depending on site access, Okopod installs ADUs using:

– Modular on-site assembly, or

– Crane installation for fully assembled units

In many cases, installation is completed in one day, followed by final utility connections and inspections.

This dramatically reduces disruption compared to traditional construction, where crews may be on-site for months.

Total Okopod Prefab ADU Timeline at a Glance

– Design and permitting: 5-26 Weeks

– Factory build in Anaheim: 5 weeks

– On-site preparation and installation: 2-4 Weeks days

Total typical timeline: 3–9 months

What Can Affect the Timeline?

While prefab ADUs are faster, a few factors can influence the schedule:

– Local permitting speed

– Utility connection requirements

– Site access and crane logistics

– Custom design complexity

Because most of the work happens in the factory, these factors tend to cause smaller delays compared to traditional builds.

Why Choose a Prefab Accessory Dwelling Unit from Okopod?

Building a prefab ADU with Okopod means:

– Faster build times

– Predictable scheduling

– Factory-controlled quality

– Reduced on-site disruption

– Local production in Anaheim, CA

Our process is designed to deliver premium ADUs efficiently, without compromising on design or durability.

If speed, quality, and reliability matter, a prefab ADU is one of the fastest ways to add a fully functional living space to your property.

By building ADUs in our Anaheim factory and installing them efficiently on site, Okopod helps homeowners across California move from idea to completion faster, with fewer surprises along the way.