Before lodgement, a NSW BASIX certificate is valid for three months; once lodged with council or an accredited certifier it rides with the DA or CDC for the life of the approval. Design changes usually need a revised certificate, and alterations valued at $50,000 or more remain inside the same rules.
How long is a BASIX certificate valid before lodgement?
The NSW Planning Portal is unambiguous: a BASIX certificate is valid for 3 months prior to submission to council or an accredited certifier. That pre-lodgement window is the practical clock most designers, certifiers and home owners watch when drawings are still moving.
The same three-month rule is hard-wired into the planning regulations. Under the Environmental Planning and Assessment Regulation 2021 section 27, a development application for BASIX development must be accompanied by a relevant BASIX certificate issued no earlier than 3 months before the day the application is submitted on the NSW Planning Portal. A parallel requirement applies to complying development certificates under section 131 of the same Regulation. In plain terms: if the certificate issue date is older than three months when you hit submit, the application is not correctly accompanied by a current BASIX certificate.
If the certificate is not lodged within three months, the Planning Portal states you will need to generate a new certificate, and that this incurs additional fees. This article does not invent dollar amounts—check the current BASIX fee schedule on the Planning Portal or BASIX tool at the time you generate.
Portal tip (quoted from the validity page, last updated 05/05/2025): to avoid additional fees, use the BASIX report function until your design is finalised and ready for lodgement, then print the certificate only when you are ready to lodge.
What happens after the certificate is lodged with council or a certifier?
Once the BASIX certificate is lodged with the council or accredited certifier, the Planning Portal states it is valid for the maximum life of the development application. In practice that means the lodged certificate travels with the approval pathway rather than expiring on a fresh three-month tick after lodgement—so long as the design it describes remains the design that is being assessed and constructed.
That does not mean you can ignore later design drift. Councils and private certifiers check BASIX commitments during assessment and again during construction. Commitments shown on the certificate must be noted on the plans, and as-built work is expected to match what was certified. If the built outcome diverges from the lodged certificate, you should expect a revision pathway—not a quiet variation.
For applicants using the NSW Planning Portal, BASIX reference numbers are validated against the BASIX tool when entered on a DA or CDC. Treat the lodged certificate as a living compliance instrument for the life of that approval, not a one-off upload you can forget.
When do design changes force a BASIX revision?
The Planning Portal’s changes guidance is clear: if you have made changes to your project, you will also have to update your BASIX certificate. That means completing another BASIX assessment and printing a new certificate.
Importantly, the Portal states there is no additional charge to revise an issued certificate where the revision relates to the same property and project recorded on the original certificate, and the certificate must also have been lodged or be valid to be lodged. Again, do not invent fee figures for first-issue certificates or for cases that fall outside that revision rule—confirm live fee settings in the tool.
Typical triggers that force a re-run of the assessment include:
- Floor area, storey or dwelling layout changes that alter conditioned floor area or thermal zoning
- Glazing schedule changes (size, orientation, U-value / SHGC assumptions used in the tool)
- Insulation, construction type or roof/wall colour assumptions that affect thermal performance
- Hot water, heating/cooling, lighting or other energy commitments shown on the certificate
- Water fixtures, rainwater tank sizing or irrigation commitments
- Pool or spa volume or equipment changes on projects that already triggered BASIX
Material change is a judgement call—but if a commitment on the certificate no longer matches the drawings you intend to lodge or build, revise before lodgement (or revise and re-supply if already lodged). Do not rely on informal plan notes to “override” a certificate commitment.
| Situation | What the Portal / Regulation says | Practical action |
|---|---|---|
| Certificate issued, not yet lodged, still within 3 months | Valid to lodge | Lodge with matching plans; keep issue date inside the 3-month window |
| Certificate issued, not lodged, older than 3 months | Generate a new certificate (additional fees) | Re-assess and re-issue before Portal submit |
| Certificate lodged with DA/CDC | Valid for maximum life of the DA | Keep commitments on plans; revise if design changes |
| Design changes after issue (same property/project) | Update certificate; no additional charge to revise if lodged or still valid to lodge | Re-run assessment; print revised certificate; update plans |
| Different property or different project | Outside the “same property and project” revision rule | Treat as a new assessment pathway; confirm fees in the tool |
Report vs certificate: how to avoid reissue fees (qualitative only)
The BASIX tool distinguishes working assessment output from the formal certificate used for lodgement. The Planning Portal’s own tip is to stay on the report pathway while the design is still moving, and only generate the certificate when you are ready to lodge. That is the cleanest way to avoid burning the three-month validity clock—and the associated need to generate a new certificate with additional fees—because early concept options never became lodgement documents.
A practical workflow many NSW practices use:
- Confirm the correct assessment pathway in the tool (single dwelling, multi-dwelling, or alterations and additions).
- Iterate glazing, insulation, services and water measures using reports while drawings are still soft.
- Freeze architectural plans and schedules that drive BASIX inputs.
- Generate the certificate only when the DA/CDC package is ready to submit on the Planning Portal.
- Diary the issue date against the intended lodgement date so the three-month window is not missed.
This is qualitative process advice only. Fee amounts change; always read the fee screen in the live BASIX tool rather than relying on blog figures.
How alterations over $50,000 fit the same rules
BASIX is not only for new houses. The Planning Portal’s About BASIX hub states that BASIX standards apply to all new residential dwellings, alterations and additions that cost $50,000 or more, and swimming pools of 40,000 litres or more.
The dedicated alterations and additions page confirms: BASIX applies to all alterations and additions in NSW that are valued at $50,000 and over and/or involve installation of a pool and/or spa with a total volume greater than 40,000 litres. Use the current $50,000 threshold—older “$25,000” figures are outdated and should not appear in client advice or SEE text.
When you start a BASIX application, pathway selection matters. The Portal’s starting-application table maps alterations valued at $50,000 or more (and pool/spa pathways at 40,000 litres or more) into the Alterations and additions assessment pathway. Once selections are made and the application is started, that pathway cannot be changed—so get the primary/secondary choices right the first time.
Validity and revision rules do not soft-pedal for renovations. An alterations certificate still has the three-month pre-lodgement validity, still rides with the lodged DA/CDC, and still needs revision when the design changes. Related giantA guides cover the renovation trigger and edge cases in more depth:
- BASIX for alterations and additions in NSW 2026
- Why you still need a certificate over $50k even with no commitments
- When NatHERS simulation is allowed over $50k
- The 40,000-litre pool trigger and the $50,000 alterations rule
Plans must match BASIX commitments
The Planning Portal states that the commitments you make for your project—as shown on the BASIX certificate—must be noted on the plans. That is one of the most common sources of RFIs and construction hold-ups: a certificate that lists a rainwater tank size, glazing performance, insulation R-value or hot-water type that the architectural drawings never show.
Before lodgement, cross-check every commitment line against:
- Floor plans and elevations (glazing sizes/orientations, roof/wall colours where relied upon)
- Sections and construction notes (insulation, construction types)
- Services drawings or notes (hot water, HVAC, lighting efficiency commitments)
- Site plan (tank location/volume, pool/spa volume where relevant)
BASIX certificates are reviewed by council and checked during the building process. Aligning plans to commitments is not a nice-to-have—it is how the certificate remains a usable compliance document through DA/CDC determination and construction.
Practical checklist before DA/CDC lodgement
- Confirm BASIX applies — new dwelling; alterations/additions ≥ $50,000; and/or pool/spa > 40,000 litres (check council if non-dwelling alterations).
- Select the correct pathway in the BASIX tool before locking inputs.
- Iterate with reports until drawings and services are final.
- Generate the certificate only when ready to lodge; diary the 3-month issue window.
- Note every commitment on plans and schedules.
- Lodge within three months of certificate issue via the NSW Planning Portal (or re-issue if the window lapses).
- If design changes after issue, revise the certificate for the same property/project and update plans before (or as part of) the amended package.
- Keep the lodged certificate aligned with what is built; expect checks during construction.
giantA provides architecture, drafting and BASIX/NatHERS services from Parramatta CBD across Greater NSW. If you need coordinated drawings and a current certificate package before Portal lodgement, see our BASIX and NatHERS service page and full services list.
Frequently asked questions
How long is a BASIX certificate valid before I lodge my DA or CDC?
Three months prior to submission to council or an accredited certifier, according to the NSW Planning Portal. EP&A Regulation 2021 sections 27 and 131 also require the certificate accompanying a DA or CDC to have been issued no earlier than three months before portal submission/lodgement.
Does the three-month clock restart after lodgement?
No. Once lodged, the Portal states the certificate is valid for the maximum life of the development application. Design changes are a separate revision issue.
What if my certificate is older than three months and I still have not lodged?
Generate a new certificate. The Portal notes this incurs additional fees—check the live tool for amounts.
Do design changes always need a new BASIX certificate?
If changes mean the project no longer matches the issued certificate, you must update it by completing another assessment and printing a new certificate. For the same property and project, the Portal states there is no additional charge to revise an issued certificate that has been lodged or is still valid to be lodged.
Should I print a BASIX certificate while the design is still changing?
Prefer the BASIX report function until the design is finalised and ready for lodgement—that is the Portal’s stated tip for avoiding additional fees tied to re-issuing certificates.
Do alterations over $50,000 follow the same validity rules?
Yes. Alterations and additions valued at $50,000 and over (and/or pools/spas over 40,000 litres) still require a BASIX certificate subject to the same three-month pre-lodgement validity and revision expectations.
Is the alterations threshold still $25,000?
No. Current Planning Portal guidance uses $50,000 and over. Do not cite $25,000.
Must BASIX commitments appear on the architectural plans?
Yes. The Portal requires commitments shown on the certificate to be noted on the plans, and certificates are checked during the building process.
Key takeaways for 2026 NSW projects
Treat BASIX timing as part of your lodgement programme, not an afterthought. Keep early work on reports, print the certificate only when plans are frozen, lodge inside the three-month window, revise promptly when the design moves, and keep every commitment visible on the drawings—whether you are building new or renovating at $50,000+.
For coordinated architectural documentation and BASIX/NatHERS support across Greater NSW, visit giantA services.
Sources
- NSW Planning Portal — Validity of the certificate and changes to the project (last updated 05/05/2025).
- NSW Planning Portal — Alterations and additions ($50,000+ / pool-spa >40,000 L) (last updated 07/05/2025).
- NSW Planning Portal — About BASIX hub.
- NSW Planning Portal — Starting a BASIX application (pathway table including alterations $50,000 or more).
- Environmental Planning and Assessment Regulation 2021 (NSW) — sections 27 and 131 (BASIX certificate issued no earlier than 3 months before DA/CDC portal submission). Current text: legislation.nsw.gov.au.