The Foundation: Understanding the NSW Planning System

Before comparing CDC and DA, it is helpful to understand the rules that govern them. The NSW planning framework is a hierarchy of legal documents that control all development.

Your project must align with these controls. The CDC and DA are simply the two different processes for demonstrating that alignment.

CDC vs DA: A Clear Comparison

These two pathways are designed for fundamentally different situations. The right choice depends entirely on your project's complexity and your property's specific characteristics.

Feature Complying Development Certificate (CDC) Development Application (DA)
Approval Type A fast, rule-based assessment against a state-wide checklist. A detailed, merit-based assessment by your local council.
Best For Standard projects on straightforward, unconstrained sites. Complex projects, custom designs, or any work on a constrained site.
Who Approves An accredited Private Certifier or your Local Council. Your Local Council only.
Key Advantage Speed. Approval can be granted in as little as 20 working days. Flexibility. Allows for thoughtful design variations from the rules.
Main Drawback Zero flexibility. You must meet every single rule with 100% precision. Time. The process typically takes 3 to 6 months, often longer.
Public Notification Neighbours are notified before work starts but cannot formally object. Neighbours are notified and have a formal period to make submissions.
Governing Rules State Environmental Planning Policies (SEPPs). Local Environmental Plans (LEP) & Development Control Plans (DCP).

The Fast Path: A Detailed Look at Complying Development (CDC)

A CDC is an excellent pathway for getting simple, low-impact projects approved quickly. It was designed to reduce red tape for developments that fit a standard mould.

What is a CDC?

A Complying Development Certificate is a combined planning and building approval that certifies a project meets all relevant standards in the state-wide Codes SEPP. It is a technical, black-and-white assessment. If your project ticks every box on the checklist, it can be approved by an accredited certifier without a lengthy council review.

What Projects Can Use the CDC Pathway?

The Codes SEPP allows many common residential projects to use this path, including:

  • New single and two-storey dwellings.
  • Alterations and additions to existing houses.
  • Secondary dwellings (granny flats).
  • Swimming pools, sheds, and carports.
  • Under the Low-Rise Housing Diversity Code (LRHDC), certain dual occupancies, manor houses, and terraces in specific residential zones.

The Golden Rule: Key CDC Development Standards in Detail

To get a CDC, your design must perfectly match the numbers in the rulebook. This is where expertise is vital, as these are not guidelines but absolute limits.

Minimum Lot Size and Width:

This is a critical two-part test that often causes confusion. First, the Codes SEPP specifies a minimum lot area, which is 200m² for a standard new home.

However, and most importantly, this only applies if your local council's own LEP permits a dwelling on a lot of that size. If your council's LEP states that the minimum lot size for a house in your zone is 450m², then the CDC pathway is not available for a new build on any lot smaller than that, regardless of the SEPP's 200m² figure. The local LEP rule for permissibility comes first.

For a dual occupancy under the CDC code, a minimum site area of 450m² and a minimum lot width of 12 metres are required.

Building Height:

  • New House: The maximum building height is strictly capped at 8.5 metres.
  • Dual Occupancy (CDC): The code allows a slightly greater height of 9.5 metres.

Floor Space Ratio (FSR):

FSR is the total floor area relative to the site area. It is calculated on a sliding scale. For a 450m² lot, the maximum gross floor area is calculated as 245m² + 25% of the area over 300m², which equals 282.5m² (an FSR of 0.62:1).

Setbacks (Front, Side, and Rear):

  • Front: Usually the average of your two neighbours’ setbacks, or a minimum like 4.5m, whichever is greater.
  • Side: This is a critical sliding scale. The minimum is typically 900mm, but this increases to 1.5m for lots over 12m wide, with further increases for two-storey walls.
  • Rear: This also scales with lot depth, often starting at a 3m minimum.

Landscaped Area:

A minimum percentage of your site must be permeable soft landscaping. For a 450m² lot, this is typically 25% of the site area.

Critical Exclusions: When a CDC is Not an Option

Even if your design fits the rules, your property itself can make a CDC impossible. A CDC is prohibited if your land is:

  • Heritage Listed: This includes being a listed item or located within a Heritage Conservation Area.
  • High Bushfire Risk: Mapped as Bushfire Attack Level BAL-40 or Flame Zone (FZ).
  • High Flood Risk: Identified as being within a flood control lot.
  • Environmentally Sensitive: Located in a coastal hazard zone, a protected wildlife corridor, or other sensitive area.
  • Affected by Other Overlays: Subject to high aircraft noise (ANEF 25+), certain easements, or other specific council exclusions.

The Flexible Path: Mastering the Development Application (DA)

When your project requires a nuanced approach, the DA is the correct and only pathway. It allows for a holistic assessment of your design on its merits.

What is a DA?

A Development Application is a formal submission to your local council. It is required for any project that does not qualify for a CDC. This is the standard process for custom architectural homes, renovations to heritage properties, and work on any challenging site.

Why Would You Need or Choose a DA?

The single greatest benefit of a DA is flexibility. It is the only pathway that allows council to consider a design that:

  • Responds to a Unique Site: For a sloping block or an unusually shaped lot, a DA allows for a design that works with the land, rather than being forced into a generic box.
  • Protects Heritage: A DA allows a heritage architect to create a design that respects the past while meeting modern needs, which a council heritage officer can then assess on its merits.
  • Justifies a Variation: If a better design outcome can be achieved by slightly exceeding a rule (like the building height), a DA allows us to prepare a Clause 4.6 Variation Request. This is a written justification explaining why the variation results in a superior planning and design outcome.

The DA Assessment: What is the Council Looking For?

Council planners do not use a simple checklist. They conduct a merit-based assessment. The key document they review is the Statement of Environmental Effects (SEE), which we prepare on your behalf. This report justifies your project against the council's LEP and DCP controls, addressing matters like neighbourhood character, solar access, privacy, and visual impact. The DA process also includes a public exhibition, where neighbours can review the plans and make submissions for the council to consider.

Your First Step: How to Know Which Path Your Project Needs

Before any design work begins, there is one non-negotiable step.

You must obtain a Section 10.7 Planning Certificate from your local council.

This certificate is the official legal record for your property. It will state definitively if your land is affected by any of the critical constraints that would prohibit a CDC, such as a heritage listing, flood risk, or bushfire mapping. It will also reference the key LEP controls, including minimum lot size, which are essential for determining CDC eligibility.

The 2024-2025 Housing Reforms: How They Affect You

Over the past two years, the NSW government implemented housing reforms to increase density. Now in late 2025, we have clarity on their impact.

The Low and Mid-Rise Housing Policy (LMRHP) was a key change. From 1 July 2024, it made dual occupancies permissible in most R2 Low Density Residential zones across NSW.

However, there was an important transition period. In many council areas where dual occupancies were newly permitted (like parts of Ku-ring-gai and the Northern Beaches), the ability to use the fast-track CDC pathway for them was delayed until 1 July 2025. This meant that for a full year, a DA was the only option in those areas.

Crucially, these reforms did not remove the key site exclusions. The prohibitions for heritage, high-risk bushfire, and flood-prone land remain firmly in place.

Real-World Examples: Approvals Across Sydney Councils

Sydney's diverse landscape means the right approval path varies greatly by location. Our extensive experience across the region provides us with this vital local knowledge.

District & Example Council Typical Site Constraints Most Likely Path & Why
North District (Ku-ring-gai) Bushfire prone land, numerous Heritage Conservation Areas. DA: A merit-based DA is almost always required to properly assess bushfire safety and heritage character.
Eastern City (Inner West) Dense heritage areas, small lots, aircraft noise. DA: A CDC is rarely an option. A DA is the standard process for navigating tight sites and heritage controls.
South District (Sutherland) High bushfire risk near national parks, some flood zones. DA: For properties near bushland, a DA with a specialist bushfire report is essential for safety and approval.
Western City (Blue Mountains) Extreme bushfire risk, steep slopes, sensitive environment. DA: This area has major constraints. A comprehensive DA is the mandatory pathway for almost all development.

The Approval Journey: What to Expect, Step-by-Step

The steps for each pathway are very different. Here is a clear outline of each journey.

The CDC Journey

  1. Eligibility Check: We use your Section 10.7 Certificate to confirm your site and local LEP rules allow for a CDC.
  2. Compliant Design: We design your project to meet every single CDC standard precisely.
  3. Lodge Application: We submit a full set of documents to an accredited certifier.
  4. Fast Approval: The certifier issues the CDC, usually within 20 days.
  5. Build and Inspect: Construction begins after neighbours are notified, with inspections at key stages.
  6. Occupation Certificate (OC): After the final inspection, you receive your OC and can move in.

The DA Journey

  1. Strategy and Design: We analyse council's LEP and DCP to create a design strategy that will earn council support. This is part of our standard architectural planning process.
  2. Prepare Application: We create a comprehensive submission, including detailed plans and a compelling Statement of Environmental Effects (SEE).
  3. Lodge with Council: We submit the application through the NSW Planning Portal.
  4. Council Assessment: A planner reviews the submission, and neighbours are notified.
  5. Determination: Council grants development consent, often with conditions of approval.
  6. Obtain Construction Certificate (CC): This is a vital post-DA step. Before building, a certifier must issue a CC to confirm the construction plans are consistent with the DA consent.
  7. Build and Inspect: Construction and inspections proceed.
  8. Occupation Certificate (OC): The final certificate is issued upon completion.

Solving Problems: Handling Refusals and Objections

Even with the best preparation, challenges can arise. An experienced architect can help you navigate them effectively.

Problem / Issue Pathway What To Do Next Expert Note
Your CDC is Refused CDC You can redesign the project to comply, or you must switch paths and prepare a full DA. This highlights why a meticulous upfront check is so important. A forced pivot to a DA adds significant time and cost.
Your DA is Refused DA You can request an internal council review of the decision, or you can appeal to the NSW Land and Environment Court (LEC). An appeal to the court is a serious legal step that requires time and resources, but it can be the right strategic move.
Neighbours Object to Your DA DA The council planner will assess their concerns on planning grounds. We can negotiate with council to address reasonable issues. We design to minimise adverse impacts from the start, which is the most effective way to prevent and manage objections.

Frequently Asked Questions (FAQ)

A DA is a more significant investment. Council application fees are higher, and you will almost certainly require specialist consultants (e.g., heritage, bushfire, arborist), which can add thousands of dollars to the upfront cost.

You can make minor changes through a "Section 4.55 Modification" application. However, significant changes will require a completely new DA. It is far more efficient to finalise your design before lodging.

It depends on your council. While the state-wide Codes SEPP has a minimum of 200m², you must first check your council's Local Environmental Plan (LEP). If the LEP for your zone requires a minimum lot size of 450m² for a dwelling, then a CDC for a new home is not possible on your 300m² lot. The local rule takes precedence.

While councils aim for 3-4 months, our experience in 2025 shows that a 6 to 9-month timeframe is realistic for a complex DA. Simpler DAs that do not attract objections can be faster.

While not mandatory, it is highly recommended. An experienced architect can quickly confirm your eligibility (checking both SEPP and LEP rules), ensure the design complies with every complex rule to avoid refusal, and produce the high-quality documents that certifiers require for a swift approval.

Conclusion: Your Project's Success Starts with Expert Advice

Choosing between a CDC and a DA is the foundational decision for your project in NSW. A CDC provides speed for standard projects on clear sites. A DA provides the essential flexibility needed for custom designs, heritage properties, and challenging sites.

Making the correct choice from the very beginning saves time, reduces cost, and removes uncertainty.

At Michael Bell Architects, our purpose is to provide that expert guidance. As a National Trust heritage award-winning firm, we have a proven track record of success with both intricate DA submissions and efficient CDC applications. We manage the entire process, coordinate the expert consultants, and champion your design. We ensure your home is not only a beautiful piece of architecture but also a smoothly approved project.

Unsure Which Path to Take? Get Expert Clarity.

Navigating the NSW approval system is complex. A mistake can cost you six months and tens of thousands of dollars. Let our 25+ years of experience guide you. Schedule a complimentary consultation with Michael Bell to ensure your project starts on the right path.