AS/NZS 3500:2025: What Changed and When It Applies
Standards Australia published the 2025 editions of all four parts of AS/NZS 3500 on 17 April 2025. Victoria made them mandatory on 20 October 2025. Everywhere else they arrive with NCC 2025, on your state's adoption date. Here is what changed, clause by clause, and what to update.
1. Which edition applies to your job
This is the part most of the industry commentary gets wrong. The publication date of a standard does not make it law. AS/NZS 3500 becomes mandatory through two separate routes, and they run on different clocks:
Victoria adopted the 2025 editions directly. The Building and Plumbing Commission (formerly the VBA) called them up under the Plumbing Regulations 2018 with a six-month transition. Either edition was accepted until 19 October 2025; from 20 October 2025 all Victorian plumbing work must comply with the 2025 editions. Source: BPC, Updated plumbing and drainage standards.
Every other state and territory picks them up through the Plumbing Code of Australia. NCC 2022 (including Amendment 2) references the 2021 editions. NCC 2025 references the 2025 editions, so they become the Deemed-to-Satisfy documents on the date your jurisdiction adopts NCC 2025: 1 May 2026 in the ACT, SA (Plumbing Code), Tasmania, Victoria and WA; 1 May 2027 in NSW and Queensland; not yet in the NT. See our NCC 2025 adoption table.
So a plumber in Melbourne has been working to the 2025 series for almost a year. A hydraulic consultant in Sydney is still, formally, documenting to the 2021 editions until May 2027, and should say which edition a drawing set is prepared to.
2. What changed in each Part
The clause references below are taken from the "major changes" list in each Part's preface.
Part 1: Water services (AS/NZS 3500.1:2025)
Clause 2.3.2: flexible hose assemblies are now classified. Every flexible hose must be one of four classes (Table 2.3.2.2), and the class is fixed by the application: connections between fixed points must be Class 2 or Class 3, hoses with an integral stop valve or trigger must be Class 4, and Class 1 hoses may not be used under static pressure. Hoses are also rated for temperature (70 °C "L" or 90 °C "H") and for submersion ("S").
Clause 5.4.2: an isolating valve immediately before each flexible hose connected to a mixer, tap outlet or cistern. This is the change that shows up on every bathroom and kitchen rough-in.
Clause 5.20: connecting miscellaneous devices and appliances to the drinking water supply (fridge ice-makers, bidet seats and the like) now has its own rules instead of sitting in a grey area.
Clauses 4.4 and 4.6: minor changes to the backflow provisions for atmospheric vacuum breakers.
Clause 2.5.3: new selection requirements for polyethylene pipe in the northern Australian regions mapped in Appendix I.
Table 2.3.2.2, summarised:
| Class | Description | Application | Max operating pressure | Max length |
|---|---|---|---|---|
| 1 | End-of-line hose with an open end | No isolation device after the inlet; not for static pressure | < 250 kPa (dynamic) | 10 m |
| 2 | Flexible connector up to and including DN 20 | Between fixed points | 1 400 kPa (static) | 2 m |
| 3 | Flexible connector over DN 20 up to DN 32 | Between fixed points | 1 400 kPa at 25 mm; 1 350 kPa at 32 mm (static) | 10 m |
| 4 | End-of-line hose with a shut-off device, pressurised | Wash-down tapware, or isolation after the hose inlet | 1 400 kPa (static) | 10 m below DN 25; 2 m at DN 25 and above |
"Fixed points" means rigid supply line to fixture, fitting, valve, tap or appliance, or supply line to supply line where the hose allows for expansion or movement.
Part 2: Sanitary plumbing and drainage (AS/NZS 3500.2:2025)
Clause 13.24: installation requirements for waterless urinals, written to reduce struvite build-up in the drain.
Clause 13.28: new provisions for connecting miscellaneous devices and appliances to a sanitary drainage system.
Section 14: updated requirements for the main lines of a sanitary drain serving multi-unit developments of three or more residential buildings.
Clause 16.2: polypropylene (PP) pipe and fittings added as an alternative for vacuum drainage systems.
Part 3: Stormwater drainage (AS/NZS 3500.3:2025)
Section 3 and Appendix F: updated requirements for residential eaves-gutter overflows and valley gutters. If your standard roof-plumbing details predate 2025, this is the one to re-check. Our free gutter and downpipe calculator works the NCC 2022 sizing.
Clause 5.3.8: new requirements for connecting miscellaneous devices and appliances (a heat-pump condensate line, for example) to the stormwater system in Australia.
Part 4: Heated water services (AS/NZS 3500.4:2025)
Clause 2.3: the same hose-class rules as Part 1, applied to heated water.
Clause 10.10.2: an isolating valve immediately before each flexible hose connected to a mixer or tap outlet, mirroring Part 1.
3. What to update
Standard details and specifications. Add the isolating valve before every flexi hose (3500.1 Clause 5.4.2, 3500.4 Clause 10.10.2) and state the hose class required at each connection.
Product schedules. Flexible hose assemblies should be specified by class and temperature rating, and should carry WaterMark certification to AS 3499.
Roof drainage. Re-run eaves-gutter overflow checks against Section 3 and Appendix F of Part 3.
Drawing title blocks. Name the edition the documentation is prepared to. Outside Victoria that is still 2021 until your state adopts NCC 2025.
Site briefings. The valve locations are the change crews notice first, and the one most often missed at rough-in.
Check it against the source
AEC Assistant searches the full text of NCC 2025 and NCC 2022 and Australia-wide planning information, resolves the edition in force for the state you are working in, and returns the clause that applies to your project with the source alongside it. Paid plans add deeper knowledge of the standards the code references. Try it free. No credit card.
Sources: AS/NZS 3500.1, .2, .3 and .4:2025 prefaces and Clause 2.3.2 (Standards Australia); Building and Plumbing Commission (Victoria); ABCB NCC 2025 adoption information. First published 6 May 2025; revised 2 September 2026 to reflect the Victorian commencement and NCC 2025 adoption.