From first consultation to move-in, an ADU is a multi-month project. Permitting is often the least predictable stage because it depends on your town's review route. With modular construction, factory work can overlap with site work once plans, permits and scheduling allow. Connections, finish work and inspections follow.
Plan for design and approvals, site preparation, construction, and final inspections. A project-specific schedule comes into focus once your property, plans and review route are understood.
Modular construction can overlap factory work with permitted site work. Your town still reviews zoning, permits and inspections; we'll help you identify those steps early.
For a recent local example, read our Norwalk 2026 ADU changes and Milford update, including size limits and the approval routes that affect planning.
No two projects move at the same pace, but they pass through the same stages. Here's what happens at each, and what can speed it up or slow it down.
Review may include zoning district, setbacks, coverage, height, parking, utilities, health, wetlands, flood, coastal or historic requirements and intended use. The applicable rules determine whether administrative review, site plan review, a special permit or another process applies; a conforming layout alone does not promise faster approval. Read our Connecticut ADU eligibility guide.
Factory production and site preparation may overlap when design, permits, production scheduling and site readiness allow. Foundation work, utility connections, finish work and inspections remain part of the project. Our modular ADU builder page explains these stages.
You can shave real time off the front end by gathering these before you start:
CT ADU begins with a preliminary review to identify site and approval questions, then develops the design and coordinates the project stages. Factory and site work may overlap where the schedule and permits allow. See our seven-step process.
Tell us about your property and goals. We'll outline the next steps, then develop a schedule as the scope, approvals and construction arrangements take shape.
Start your free feasibility review →This guide is general information, not legal advice. ADU rules and permit timelines vary by Connecticut town and change over time — always confirm current requirements with your local planning and zoning department.
Common questions about ADU permits and schedules.
Permit timing depends on the review route, a complete application, agency workload and any revisions. Ask your town which reviews are required and what its current process involves.
Yes. A modular ADU is reviewed against the same zoning and building codes as any ADU. Off-site construction changes how it's built, not whether it needs zoning review, permits, a foundation, and inspections.
An as-of-right route may apply where the proposal meets the governing requirements. Other proposals may require site plan review, a special permit or another process. Determine the applicable state and local provisions for the specific property; as-of-right does not waive permits or inspections.
Hearings, septic or wetlands review, missing survey information, plan changes and complex utilities can extend the schedule. Identify these early with your design team and town.
Sometimes. Factory production and site preparation may overlap when permits, design, production scheduling and site readiness allow. Delivery still depends on the foundation and access being ready, and final connections and inspections remain necessary.
