Bombo Granny Flat planning starts with the property, current planning controls and a realistic project brief. Use this guide to identify the checks to complete before design or construction commitments are made.
Bombo Granny Flat: planning essentials
A well-scoped project considers approval pathways, site constraints, services, budget and long-term use together.
A secondary dwelling (commonly called a granny flat) is a self-contained dwelling established in conjunction with a principal dwelling on the same lot. It may be within, attached to or separate from the principal dwelling. Its legal classification comes from the approved proposal and use, not from a builder’s product name, physical appearance or construction method.
Bombo is identified by the Australian Bureau of Statistics as SAL 10457. SAL means the ABS Suburbs and Localities geography; SAL boundaries are statistical approximations and are not cadastral, zoning or council boundaries. The canonical locality record covers approximately 1.7979 square kilometres and six mesh blocks, with its recorded area overlapping the ABS statistical LGA named Kiama. That statistical name must be distinguished from the formal council organisation name, Kiama Municipal Council. Neither the SAL nor LGA overlap proves which council administers a legal parcel.
This guide separates the limited verified locality evidence from statewide planning guidance. Before relying on any rule, identify the address, lot and deposited plan, confirm the responsible council, and obtain current property records. A suburb name cannot establish zoning, title restrictions, site constraints, approval eligibility or development rights.
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Local granny-flat overview
The 2021 Census Bombo QuickStats counted 175 people and 72 private dwellings in the Bombo SAL. These are historical figures from the 2021 Census, not current population, housing-supply or market evidence, and they say nothing about whether a particular property can accommodate a secondary dwelling. The small locality count also makes broad demographic, rental-demand or investment conclusions especially unsafe.
The verified locality record supplies geographic context but little property-specific planning information. It does not verify a shared Bombo zoning, typical lot size, development pattern, service capacity, hazard profile or lawful building history. Those matters must therefore be investigated for the actual land rather than filled with generic locality claims.
Under the NSW Government’s secondary-dwelling guidance, a secondary dwelling is associated with a principal dwelling on the same site. Both dwellings remain on the same lot; this planning pathway does not create a separately subdividable, separately titled or independently saleable home. A proposal seeking another ownership or subdivision outcome may require a different planning classification and professional advice.
NSW guidance says secondary dwellings are permitted in residential zones R1, R2, R3, R4 and R5 and may be permitted in another zone where the applicable local environmental plan allows them. Permissibility is not approval. Rural and non-residential land must be checked against its local environmental plan rather than assessed using residential-zone assumptions.
The first property screen should use the NSW Planning Portal Spatial Viewer, followed by formal title, survey and council information. Verify the zone, applicable environmental planning instruments and any mapped controls. Check the title and deposited plan for easements, covenants, restrictions and legal access; locate sewer, drainage and utility assets; and establish the lawful status of the principal dwelling and any structure proposed for conversion. Planning approval does not necessarily override a private title restriction.
Address-level evidence is also needed before mentioning heritage, bushfire, flooding, biodiversity, coastal hazards, acid sulfate soils, contamination, mine subsidence or another constraint as affecting the land. This guide does not assert that any of those matters applies, or does not apply, throughout Bombo. The useful action is to identify verified constraints through official records and then obtain only the specialist advice relevant to them.
Council rules and approval pathway
The ABS locality record places Bombo’s statistical area within the Kiama LGA geography. If formal parcel records confirm that Kiama Municipal Council is responsible for the address, its Local Environmental Plan information identifies the Kiama Local Environmental Plan 2011 and retains a deferred-matter caveat. The official Kiama LEP 2011 record and maps should be read together with the written instrument. Their applicability remains conditional on confirming the legal parcel, current mapping and any other instrument affecting it.
Also check the applicable development control plan, site-specific instrument, contribution plan, application requirements, fee schedule, stormwater policy, waste requirements and driveway or vehicle-crossing rules. Kiama Municipal Council offers planning and development advice services for property zoning, constraints and pre-lodgement enquiries. Use that route only after confirming council responsibility for the property.
A secondary dwelling has two potential approval pathways:
- A development application is assessed by the responsible council against the controls and assessment matters applying to the land and proposal.
- A complying development certificate is a standards-based approval that may be issued by the council or an appropriately registered certifier only when every applicable requirement is satisfied.
For the Housing SEPP complying-development pathway, NSW guidance identifies a lot area of at least 450 square metres, except where the secondary dwelling is located entirely within an existing dwelling house. This is one bounded eligibility test, not a universal minimum for a council-assessed application and not sufficient by itself. The zone, principal dwelling, mapped exclusions, proposal type and all current statutory standards still require checking.
Read the current State Environmental Planning Policy (Housing) 2021, including Schedule 1, with the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008. The NSW explanation of complying development and the certifier’s role is useful guidance, but a certifier cannot waive statutory standards or exclusions.
Do not import a floor-area, setback, height, landscaped-area or site-coverage standard from an old instrument, another council or another development type. Confirm each control under the selected pathway. The Housing SEPP does not itself require additional parking for a secondary dwelling, although existing consent conditions, loss of parking, access and driveway design may still need assessment.
A concept plan, quotation, BASIX certificate or builder statement is not development approval. After approval, the project may require construction certification, prescribed inspections and compliance evidence. Obtain the required occupation certificate before occupying or using a new building or implementing an approved change of use.
Costs and budgeting
There is no verified Bombo-wide construction price that can safely represent an individual project. Build the budget from a documented design, property investigations and itemised quotations. Access, levels, ground conditions, existing structures, service routes, drainage, required reports and finish selections can materially alter the scope.
Organise the budget into clear work packages:
- title documents, survey, service searches and approval-history research;
- design, planning, engineering, BASIX and relevant specialist reports;
- application, certifier, inspection and certificate charges;
- council contributions and authority fees where applicable;
- demolition, excavation, foundations, retaining and site preparation;
- building work, fixtures and finishes;
- sewer, water, electricity, telecommunications and stormwater work;
- paths, fencing, landscaping, waste areas and site reinstatement;
- insurance, contract administration and a risk allowance based on unresolved items.
Verify current fees and contributions from the responsible authority using the actual proposal assumptions. Do not transfer figures from another property or an expired fee schedule. For conversions, investigate structural adequacy, moisture protection, fire safety, ventilation, insulation and work needed to establish the approved residential use. Prefabricated or modular construction may still involve transport, cranage, foundations, connections, approvals and certification.
Compare quotations against the same drawings and inclusions schedule. Identify exclusions, provisional sums, prime-cost items, escalation provisions, owner-supplied work, service allowances, approval responsibilities, BASIX commitments and variation procedures. A headline package price is not a complete feasibility budget unless its assumptions match the site and approved documents.
Current Building Commission NSW contract guidance states that residential building work over $5,000 requires a written contract, with more extensive large-job contract requirements above $20,000, and identifies a maximum deposit of 10%. Home Building Compensation cover applies to work valued at $20,000 or more including GST. Where required, verify the certificate using the official HBC Check before paying the builder. Recheck these consumer-protection requirements at contract date.
Bombo Granny Flat: council and site checks
Confirm property-specific requirements with the responsible council or certifier before relying on general guidance.
Design and site considerations
Begin design with an accurate feature-and-level survey and a record of boundaries, buildings, access, vegetation, levels and services. Define whether the proposal is within, attached to or separate from the principal dwelling. If it involves a garage, shed, studio or other existing structure, obtain approval records rather than assuming the structure is lawful for habitation.
Test the layout against the site and the controls confirmed for the selected pathway. Coordinate the relationship between the two dwellings, including entries, pedestrian movement, privacy, overlooking, daylight, ventilation, noise and usable outdoor areas. Provide practical locations for bins, clothes drying, storage and maintenance access. Where vehicles use the site, assess manoeuvring, gradients, sight lines, existing parking and driveway capacity.
Map every proposed service route early. Sewer levels, stormwater disposal, utility clearances, easements and construction access can affect siting and foundation design. Confirm authority requirements before fixing the building position. Stormwater must have a lawful engineered solution; it should not be assumed that runoff can discharge to a boundary or adjoining land.
Use the verified property checks described above to shape the consultant brief. For example, a mapped or property-specific constraint may trigger design changes, an assessment report or authority consultation. Avoid ordering a generic collection of reports before the relevant issue has been identified, but do not defer a necessary investigation until after pricing or contracting.
BASIX addresses water, energy use and thermal performance for residential development. The correct classification depends on whether the work is a conversion, a new secondary dwelling, or a new principal and secondary dwelling in one project. Follow the Planning Portal’s secondary-dwelling BASIX project guidance and integrate the commitments into the drawings, specifications, quotation and contract.
Design coordination should continue through engineering and certification. Orientation, glazing, shading, insulation, ventilation, acoustic separation and durable materials affect both compliance and day-to-day amenity. Before final pricing, have the designer reconcile the planning documents, BASIX commitments, engineering details and applicable building requirements so that inconsistent documents do not become variations on site.
Rental and investment considerations
Rental analysis should follow, not precede, confirmation of lawful approval and occupation. Retain the development consent or complying development certificate, approved plans, inspection records and occupation certificate. The secondary dwelling remains legally connected to the principal dwelling on the same lot, which affects access, maintenance, insurance and management arrangements.
If the approved premises are rented under a residential tenancy, consult current NSW Fair Trading guidance on residential tenancy agreements. It explains the written agreement and standard terms as well as landlord and tenant obligations. The governing legislation is the Residential Tenancies Act 2010.
Do not assume that family occupation, a licence, short-stay use, rooming accommodation and a standard residential tenancy have identical rules. Confirm the proposed arrangement against the approved use, planning controls, tenancy requirements and insurance policy. Obtain legal advice where the arrangement does not fit an ordinary residential tenancy.
For practical management, define access, parking, mail, bins, outdoor areas, noise expectations, garden care and responsibility for shared services. Check whether utilities will be separately metered and obtain advice on lawful charging arrangements. Plan how maintenance workers can reach equipment and how repairs affecting both dwellings will be coordinated.
Use recent comparable evidence from lawful premises when assessing possible rent, and distinguish achieved rents from online asking prices. Include vacancy, management, maintenance, utilities, insurance, finance and future repairs in any personal model. A licensed property manager may provide current local evidence, while finance, insurance and tax advisers can address the owner’s circumstances. The 2021 Census figures are not a substitute for this due diligence.
Choosing a granny-flat builder
Tender only when the site investigations, approval strategy and scope are developed enough for meaningful comparison. Give each tenderer the same drawings, engineering information, BASIX commitments and inclusions schedule. Require separate identification of design, approvals, site works, services, external works and exclusions.
Identify the legal entity that will sign the contract. Use the official NSW builder and tradesperson licence check to verify its licence number, current status, category and conditions. An ABN, association membership, online review or salesperson’s statement is not a licence check. Repeat the search immediately before signing.
Ask for recent references involving comparable secondary dwellings and inspect completed work where the owner permits it. Discuss occupied-site management, access restrictions, neighbour protection, drainage, service connections, variations, defects and handover. Treat references as due-diligence evidence rather than endorsement.
Review the proposed contract against the consumer-protection rules described above. Read the Consumer Building Guide, match progress payments to completed stages, and understand the variation, delay, extension-of-time, dispute and termination provisions. Verify current statutory warranty information applicable to the work and check that the contract does not misstate those protections.
Where Home Building Compensation cover is required, confirm the certificate against the builder, site and contracted work through HBC Check before making a payment. Do not rely on a logo, sample policy or unchecked attachment. Confirm insurance responsibilities for the work site and the occupied principal dwelling with the relevant insurers.
The final scope should address provisional sums, excavation, rock, spoil removal, retaining, foundations, cranage, service connections, stormwater, metering, paths, fencing, landscaping and reinstatement. It should allocate responsibility for consultants, applications, authority approvals, inspections and approved variations. Require handover records including certificates, warranties, manuals and documents needed for occupation certification.
Planning and feasibility checklist
- Confirm the address, lot, deposited plan, title and lawful principal dwelling.
- Verify the responsible council from formal parcel records.
- Check zoning and mapped controls in the Spatial Viewer.
- Read the current applicable LEP, DCP and site-specific instruments.
- Obtain a survey, title search, service information and approval history.
- Identify relevant easements, restrictions, assets and verified constraints.
- Define the proposal as internal, attached, separate or a conversion.
- Test both approval pathways against current statutory controls.
- Confirm design standards with the council or registered certifier.
- Coordinate BASIX, engineering, authority and certification documents.
- Verify current fees, contributions and service requirements.
- Compare complete, itemised quotations on the same scope.
- Check licences, contract protections, warranties and HBC cover.
- Obtain approval before starting work.
- Complete required inspections and obtain the occupation certificate.
- Use current Fair Trading documents if establishing a tenancy.
Next steps for your Bombo Granny Flat
Before progressing a Bombo Granny Flat, compare the evidence in our planning guides and use the NSW suburb finder to locate relevant local guidance.
A successful Bombo Granny Flat proposal should be checked against the current planning instrument, title constraints, servicing needs and a documented project budget.