Preparing these in advance makes for a smoother lodgement, though it does not by itself determine the outcome, which remains subject to assessment. The sections below explain each group in more detail.

Before you start: a CDC fit check

A checklist is most useful once you have reason to believe complying development may apply. Under the Housing SEPP 2021, the CDC pathway is generally available when the site and proposal meet all the relevant standards. If any standard is not met, the site may fall outside CDC and need a different route.

Confirming this first avoids preparing a full document set for a site that cannot use CDC. For the detailed standards, see our granny flat regulations in NSW page, and if you are unsure whether a granny flat suits your block at all, our guide on whether you can build a granny flat on your property in NSW is the right starting point.

Site and title checks

Before documents, confirm the basics about the land: your zoning and whether a secondary dwelling is permitted, your lot size and width, and your title type, since strata or company title generally does not suit the streamlined pathway. Noting where the existing house, boundaries and easements sit also helps, as these shape where a granny flat can go.

These checks are quick to start, and a single factor such as title type or an easement can change the pathway before any plans are drawn.

Plans and design documents

Plans are the core of a CDC application. A certifier commonly needs a site plan showing the proposed dwelling in context, floor plans, elevations and sections. These need to reflect a design that meets the applicable standards, so it helps to develop the design with the site rules in mind rather than adjusting later.

If you are still shaping the design, our granny flat designs and granny flat floor plans pages show layouts that commonly suit Sydney blocks. The plans in your application still need to be prepared to the standard a certifier requires for your specific proposal.

Survey, BASIX and technical documents

Beyond plans, a few technical documents are commonly required:

• A survey identifying boundaries, levels, and the position of existing structures and features
• A BASIX certificate, which is required for a secondary dwelling and sets energy and water commitments that flow into the design
• Engineering details such as structural and, where relevant, geotechnical information
• Stormwater and drainage documentation

The exact set depends on your site and proposal, so treat these as commonly needed items rather than a fixed list. A certifier can confirm what your particular application requires.

Services, stormwater and drainage information

How water and services are handled is a practical part of readiness. Stormwater and drainage details show where roof and surface water will go, and how the dwelling connects to the existing system or an approved alternative. Sewer and services location can also matter, since building over or near certain infrastructure may need specific treatment.



Gathering this early avoids a common holdup, where an otherwise complete application stalls on missing drainage or services information.

Site constraints to check before lodging

Some sites carry constraints that add requirements or change the pathway. Before lodging, check whether any of these apply:

•  Flood-affected land, which may need controls or reports
• Bushfire prone land, which may trigger construction and siting requirements
• Heritage listings or conservation areas, which may add assessment
• Easements, slope, drainage and trees, which may limit siting

If a constraint applies, a relevant report or specialist input may be needed, and in some cases the constraint moves the project outside CDC. Confirming this against your council mapping and a site assessment is part of being ready.

What a certifier may review

A certifier assessing a CDC generally checks that the proposal meets each applicable complying development standard and that the documents are complete and consistent. That usually means reviewing the plans against setbacks, floor area, height and siting standards, confirming BASIX and engineering are in order, and checking that any constraint has been addressed.

Because a CDC is a compliance check rather than a merit assessment, the emphasis is on meeting the standards precisely. This is why accurate, complete documents matter, and why a gap or inconsistency can hold things up.

Common checklist mistakes

A few recurring issues slow down otherwise ready applications:

• Designing before checking the standards. Locking in a layout the site cannot support under CDC.
• Assuming CDC applies. Preparing documents before confirming the site suits complying development.
• Incomplete drawings. Submitting plans that miss details a certifier needs.
• Overlooking constraints. Missing flood, bushfire or heritage mapping that changes requirements.
• Leaving drainage late. Treating stormwater and services as an afterthought.

Most of these come back to sequencing: confirm eligibility, then design to the standards, then document thoroughly.

What to do if your site does not fit CDC

If a standard is not met or a constraint gets in the way, CDC may not be available, but that does not necessarily end the project. A Development Application assessed by council is often the alternative, since it takes a merit-based view rather than requiring every fixed standard to be met.

Working out which pathway suits your property is the practical next step, and it is covered on our granny flat approval process page. The key point is that not fitting CDC is a signal to reassess the pathway, not automatically a dead end.

Frequently asked questions

What documents do I need for a granny flat CDC in NSW?

A CDC application commonly needs a site plan, floor plans, elevations and sections, a land survey, a BASIX certificate, engineering details and stormwater or drainage documentation, plus any report tied to a site constraint such as flood or bushfire. The exact set depends on your site and proposal, so treat this as a common list rather than a fixed requirement. A registered certifier can confirm what your specific application needs. Preparing complete, consistent documents up front is one of the most effective ways to avoid delays, though it does not by itself determine whether the standards are met.

Does having a CDC checklist guarantee approval?

No. A checklist helps you confirm whether the site may suit complying development and gather the documents a certifier commonly needs, but it does not guarantee CDC approval. A Complying Development Certificate is issued only when the property and proposal meet all the applicable standards, and that is confirmed through assessment. Being well prepared makes the process smoother and reduces avoidable holdups, but the outcome still depends on whether your specific site and design comply. Treat the checklist as readiness, not a promise of the result.

How do I know if my granny flat qualifies for CDC?

Complying development is generally available under the Housing SEPP 2021 when the site and proposal meet all the relevant standards, including zoning, lot size and width, floor area, setbacks, height and any site constraints. If every standard is met, the CDC pathway may apply. If one is not, the site may fall outside CDC and need a Development Application instead. Because this depends on your specific property, a site assessment and, where needed, advice from a certifier are the reliable way to confirm whether CDC is realistic before you prepare a full document set.

Is a CDC the same as a building permit for a granny flat?

People use the phrase granny flat building permit loosely, but in NSW the relevant approval is usually a Complying Development Certificate, or a Development Application followed by a construction certificate where CDC does not apply. What matters is confirming which pathway suits your property rather than the general term.



What happens if my site does not meet the CDC standards?

If a standard is not met or a site constraint gets in the way, the complying development pathway may not be available, but the project is not necessarily over. A Development Application assessed by council is often the alternative, because it takes a merit-based view rather than requiring every fixed standard to be satisfied. The practical step is to reassess which pathway suits your property, ideally with input from a certifier or planning professional, so the design and documents are prepared for the route that actually applies to your block.