QBCC Form 4 (the Notifiable Work Form 4) is the formal plumbing compliance certificate issued by the licensed plumber at completion of any notifiable plumbing work in Queensland. For a new home build, you cannot get your certificate of classification (the document that lets you move in) without it.
What Form 4 certifies
- The plumbing work was performed by a licensed plumber (QBCC licence number listed)
- The installation complies with AS3500 (national plumbing and drainage code)
- The installation complies with the Plumbing Code of Australia
- The installation has been pressure-tested
- Any backflow prevention devices have been installed correctly
- Drainage falls are to specification
- Sewer or septic / AWTS connection is correct
When you need Form 4
- Every new build (residential or commercial)
- Major renovations involving drainage or water supply changes
- Bathroom renovations (yes, even simple ones)
- Hot water unit replacements where the type is changing (e.g. gas storage to heat pump)
- Septic or AWTS installation
- Backflow prevention device installation or replacement
- Water main connection or replacement
- Sewer connection or replacement
When Form 4 is NOT required
- Minor maintenance (washer replacement, blocked drain clearance, like-for-like tap swap)
- Some emergency repairs (depending on scope)
- Like-for-like hot water unit replacement without changing type or location
Who issues Form 4
The licensed plumber who performed the work issues Form 4 at completion. The certificate must be lodged with the Queensland Building and Construction Commission (QBCC) and a copy provided to the homeowner.
You cannot issue Form 4 yourself. You cannot get an unrelated party to issue one. The licensed plumber who actually performed the work is the only person authorised.
What is on Form 4
- Address where the work was performed
- Description of the work (new build, renovation, etc)
- Date of completion
- Licensed plumber's name and licence number
- Statement that work complies with AS3500 and Plumbing Code of Australia
- Hydrostatic pressure test result
- Schedule of fixtures installed
- Plumber's signature
Form 4 vs gas compliance certificate
Form 4 is for plumbing (water and drainage). Gas compliance certificate is separate, issued by a licensed gas fitter for any gas work. Most new builds need both, plus a backflow prevention testing certificate if backflow devices are installed.
What we provide on every new build
- QBCC Form 4 plumbing compliance certificate
- Gas compliance certificate for every gas appliance installed
- Hydrostatic pressure test certificate
- Backflow prevention testing certificate (if applicable)
- Hot water unit warranty registration in your name
- As-built drainage drawing
- Workmanship guarantee documentation
Handed over as a single PDF pack at handover, lodged with the relevant authorities, ready for your certifier to issue the certificate of classification.
What happens if you do not have Form 4
Your certifier cannot issue your certificate of classification, which means you cannot legally move in to the new home. The certifier will require Form 4 before signing off.
If you have a Form 4 from an unlicensed plumber, it is invalid and the certifier will reject it. The plumber must hold a current QBCC plumbing licence at the date of work.
For renovations, Form 4 is required before final inspection and council sign-off. Selling the house later without Form 4 for past renovations may be flagged at pre-sale inspection.
Keep the paperwork safe
File Form 4 with other house paperwork. You will need it for:
- Certificate of classification (new builds)
- Council final inspection (renovations)
- Future insurance claims
- Sale of the house
- Future plumbing work where the existing system is being modified
QBCC also keeps a digital record of every lodged Form 4. You can request a copy from them if you lose yours, but having your own copy is faster than going through the regulator.
The notifiable work classification, what triggers Form 4
Not every piece of plumbing work triggers Form 4 lodgement. The Queensland Plumbing and Wastewater Code defines notifiable work as plumbing or drainage work that affects the integrity, safety or compliance of the water supply or sewer system, requires QBCC notification and a Form 4 compliance certificate on completion. Examples of notifiable work, water service installation or modification (new house water supply, modification to existing service), sewer or drainage installation or modification (any new drainage run, any reconfiguration of existing), hot water unit installation if the type, location or capacity is changing (heat pump replacing electric storage, gas storage replacing electric, relocation to a different wall), backflow prevention device installation or replacement, bathroom or kitchen renovation involving wet-area drainage changes, septic or AWTS installation or replacement, and any work on commercial or food-service premises. Examples of non-notifiable work that does not require Form 4, like-for-like tap or fixture swap (same location, same type), washer or cartridge replacement, blocked drain clearance, hot water element replacement, and minor leak repair. The grey area is renovations where work scope expands during construction, what started as a like-for-like reno can quickly become notifiable if you decide to move the toilet or add a second basin. Our practice on every renovation quote is to declare upfront whether the scope is notifiable, lodge the work, and issue Form 4 at completion, this protects you against the certifier coming back later asking for paperwork that was never issued. Operators who skip Form 4 to keep the price down are passing the regulatory risk to you, not absorbing it themselves.
The QBCC lookup, how to verify your plumber's licence and Form 4 history
The Queensland Building and Construction Commission maintains a public licensee search at qbcc.qld.gov.au where you can verify any plumber's licence status, the licence class held, and whether they are current and in good standing. Before engaging any plumber, particularly for notifiable work, this 30-second lookup is worth doing. Search by name, business name, or licence number. The licence search shows the licence class (plumbing, gas fitting, drainage, hydraulic services), the issue date, the expiry date, and any conditions or restrictions on the licence. If the plumber cannot supply their licence number on quote, or the licence does not appear on the QBCC register, walk away. After completion of notifiable work, the QBCC also maintains a record of every lodged Form 4 against the licensee and the property address, you can request a copy through the QBCC if you need it for sale of the property, insurance claim, or future renovation work. The records are kept indefinitely, so a Form 4 lodged in 2010 is still retrievable in 2026. Worth knowing the system exists, most homeowners do not realise the regulatory infrastructure behind the certificate they get handed at the end of a job.
What happens when Form 4 is missing for past work
Many older renovations were done without Form 4 lodgement, either because the operator was unlicensed (cash work), the work was wrongly classified as non-notifiable, or the paperwork was lost before the certifier signed off. This becomes a problem when you sell the property and the buyer's solicitor checks for compliance documentation, or when you renovate and the new plumber discovers existing work that doesn't comply with the current code. The remediation path depends on the work scope. For minor work where compliance is evident on inspection, a licensed plumber can sometimes issue a retrospective Form 4 after re-inspecting and confirming the existing work meets the standards in force at the time it was done. For larger work, particularly drainage or water service work that is not visible without excavation, the path is either bring the work up to current code and issue a current Form 4, or document the non-compliance and disclose it at sale. We have run several of these audit-and-certify jobs for clients who inherited unpermitted work from previous owners, typical cost $400-1,500 for the inspection, documentation, and any minor remedial work to meet current standards. The cost is much lower if caught before sale, because there is time to remediate, versus discovering it during a buyer's pre-purchase inspection when the timeline forces panic decisions.
Form 4 and your insurance, the link people miss
Most household insurance policies in Queensland have a clause that excludes claims arising from work that was not done by a licensed tradesperson or work that did not meet the regulatory standards in force at the time. For plumbing work, the documented proof of compliance is Form 4. If you make an escape-of-water claim for a burst flexi hose or a failed hot water unit, the insurer may ask for evidence that the original installation was done compliantly. No Form 4, no evidence, potential claim denial or significant excess. The link is not always enforced by insurers in practice, particularly for smaller claims, but on larger claims (whole-bathroom flood damage, multi-room water damage) the documentation chain matters. We tell every new-build and renovation client the same thing, file your Form 4 with your insurance paperwork, scan a digital copy to your cloud drive, and keep a photo of the certificate in your phone. The five minutes of filing at completion saves potentially thousands at claim time. Body corps for apartment buildings should also keep Form 4 records for common-property plumbing work, because the same insurance principle applies at body corp level and the cost of a denied claim is shared across all owners.
Selling a house with unpermitted past plumbing work
One of the most common scenarios where Form 4 history becomes a problem is at sale time. The buyer's conveyancing solicitor and pre-purchase inspector will routinely check for compliance documentation on any visible plumbing work done since the original certificate of classification was issued. If the property had a bathroom renovated 8 years ago by an unlicensed operator with no Form 4 lodged, the gap shows up in the QBCC records and can become a settlement issue. The buyer's solicitor may require either retrospective certification (a current licensed plumber inspects the work and lodges a current Form 4 if the work meets standards), remedial work to bring the installation up to current code, or a settlement adjustment to cover the cost of either. Settlement adjustments for documented compliance gaps typically run $1,000-5,000 depending on scope, with the cost coming directly out of the seller's proceeds. We have seen sellers lose $3,000-8,000 at settlement because of compliance gaps from past unlicensed work, money they would have saved by paying the small premium for licensed work at the time. The lesson, every plumbing job on a house you ever expect to sell should generate Form 4 if it is notifiable work, and the certificates should be filed with the property records for the duration of ownership. Modest upfront cost, much larger downstream protection.