Unapproved Granny Flat NSW: Risks & Next Steps

Common ways homeowners discover the problem

Most people do not go looking for this. It tends to surface at a specific moment:

• Buying a property where the granny flat is not shown on approved plans during conveyancing or a building inspection.
• Selling, when a purchaser's solicitor or lender queries the second dwelling.
• Refinancing, when a valuer or lender notices the dwelling is not approved.
• Insuring or claiming, when an insurer asks about approvals.
• Renting out, when a tenancy or council query raises the issue.
• Renovating, when a certifier or council checks existing approvals.

Whatever the trigger, the same principle applies: it is better to understand the position early than to be caught out mid-transaction.

Main risks of an unapproved granny flat



The risks fall across several areas, and they interact. The table below is a plain-language guide to what an unapproved granny flat may affect. It is general information, not a prediction of what will happen in your case.

The point of this table is not to alarm, but to show why an unapproved granny flat is worth resolving rather than ignoring. How each risk plays out depends on your property and circumstances.

What to check before taking action

Before you decide anything, build a clear picture of the current position:

• Council records. What was actually approved on the property, and when.
• Your documents. Any certificates, stamped plans, or correspondence you hold.
• The structure itself. Whether it appears to have been built to a reasonable standard, noting you may need a professional assessment.
• How it is being used. Whether current use matches any approval that exists.
• Your title and site. Zoning, constraints and anything that affects what is possible.

This is fact-finding, not commitment. Knowing what exists on record is the foundation for every decision that follows, and it stops you acting on guesswork.

Can an unapproved granny flat be approved later?

Sometimes, but it is not automatic, and it cannot be assumed. In NSW there are two pathways homeowners most often look at, and they address different problems.

The first is a Building Information Certificate (BIC). A BIC is a council document that relates to the existing building, essentially council's position on whether it will take certain action about the structure as it currently stands. It is often relevant where the concern is the building itself and its construction rather than the planning permission for its use.

The second is a retrospective or regularisation Development Application (DA). A retrospective DA is generally the relevant route where the issue is the use of the structure as a secondary dwelling, or where works were carried out without the planning consent they needed. It asks council to assess and, if appropriate, grant consent for what already exists.

Neither pathway is guaranteed. A BIC may relate to the building, a retrospective or regularisation DA may be needed for the use as a dwelling, and in some cases both the building and its use need addressing. Which applies, and whether it is achievable, depends on the structure, how it was built, the site and your council, so advice from a registered certifier or your council is essential before you rely on either route.

If regularisation is not realistic, the options may involve modifying the building to meet standards, changing how the space is used, or stopping its use as a separate dwelling. No one can promise an outcome in advance, because it rests on assessment of your specific building and circumstances. The granny flat approval process page explains how approval works for new builds, which gives useful context for the standards involved.

What if you bought a property with an unapproved granny flat?

Discovering it after purchase is common and stressful, but manageable if you take it step by step. Start by confirming the facts through council records rather than relying on what you were told at sale. Then get a professional view on the structure and the options for your specific situation.

Depending on what you find, the path might involve seeking to regularise the dwelling, making changes to meet standards, or in some cases reconsidering how the space is used. Because outcomes vary so much by property, this is a situation where tailored advice from a certifier, council or planning

professional matters more than general rules. If you are weighing up building or rebuilding a compliant dwelling instead, our guide on whether you can build a granny flat on your property in NSW is a useful starting point.

What not to do

A few actions tend to make an unapproved granny flat harder to resolve:

• Renting it out regardless. Placing a tenant in an unapproved dwelling can carry legal and insurance consequences.
• Advertising it as approved. Presenting the dwelling as compliant when it is not can create problems at sale.
• Renovating over the problem. Adding works to an unapproved structure can compound the issue.
• Assuming records are wrong. Believing approval exists without confirming it in council records.
• Ignoring it. Hoping the issue will not surface, when transactions and claims routinely bring it up.

Avoiding these keeps your options open rather than narrowing them.

Practical next steps

A sensible sequence for most homeowners looks like this:

1. Pause any use that assumes the dwelling is approved.
2. Collect every relevant document you have.
3. Request council records to confirm what was actually approved.
4. Engage a registered certifier or planning professional to assess the structure and options.
5. Decide on a path based on advice specific to your property, whether that is regularising, modifying, or changing how the space is used.

Working through it in this order means each decision rests on facts and advice rather than assumption. Our process page shows how we approach assessment and planning for a compliant build if that becomes the direction you take.

Frequently asked questions

Is it illegal to have an unapproved granny flat in NSW?

An unapproved granny flat means the dwelling does not have the planning or building approval it should, which can expose you to council enforcement and other consequences. Whether and how that is acted on depends on the specific situation, so it is not something to self-diagnose or assume away. The safest approach is to confirm what is actually approved through council records, then get advice from a certifier or your council about your particular circumstances. This guide is general information and not legal advice, so professional input on your property is important.

Can I rent out an unapproved granny flat?

Renting out a dwelling that is not approved for use as a secondary dwelling can carry legal and insurance risks, and it is not something to do on the assumption it will be fine. Beyond the legal position, an insurer or a tenancy issue can bring the approval status to light at an inconvenient time. Before considering any rental use, confirm the dwelling's approval status through council records and seek advice on whether lawful rental use is possible for your specific property. If it is not currently approved, that needs resolving first.

How do I find out if my granny flat is approved?

Start with council records, which show what was formally approved on the property and when. Compare that against the structure that actually exists and how it is being used. If you hold certificates, stamped plans or council correspondence, gather those too. Where the picture is unclear, a registered certifier or planning professional can help interpret the records and assess the building. This fact-finding is the essential first step, because every later decision depends on knowing what is genuinely on record rather than what was assumed at purchase.

Can an unapproved granny flat be made legal?

Sometimes, but it depends entirely on the structure, how it was built, the site and your council. Two pathways commonly come up: a Building Information Certificate, which relates to the existing building, and a retrospective or regularisation Development Application, which is generally relevant where the issue is use as a secondary dwelling or works done without consent. Neither is guaranteed, and some structures need changes first or may not qualify. If regularisation is not realistic, the alternatives can involve modifying the building, changing its use, or stopping use as a separate dwelling. The reliable step is to have a certifier, or your council, review your situation and advise on what may be possible for your property.

I bought a house with an unapproved granny flat, what now?

First, confirm the facts through council records rather than relying on what was said during the sale. Then get a professional assessment of the structure and your options. From there, the path might involve seeking to regularise the dwelling, making changes to meet standards, or rethinking how the space is used, depending on what the assessment shows. Because outcomes vary so much between properties, tailored advice from a certifier, council or planning professional is worth more here than any general rule, so make that your priority before renting, renovating or reselling.