AS/NZS 3500.4:2025 Plumbing and drainage, Part 4: Heated water services
Standards Australia/Standards New Zealand
Supersedes: AS/NZS 3500.4:2021 Plumbing and drainage, Part 4: Heated water services
Draft Designation: DR AS/NZS 3500.4:2023This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee WS-014, Plumbing and Drainage, to supersede AS/NZS 3500.4:2021.
The objective of this document is to provide deemed to satisfy solutions to comply with —
(a) the National Construction Code (NCC) Volume Three, Plumbing Code of Australia (PCA), and
(b) the New Zealand Building Code (NZBC), Clause G12 Water Supplies.
A list of all parts in the AS/NZS 3500 series for plumbing and drainage can be found in the Standards Australia and Standards New Zealand online catalogues.
The major changes in this revision are as follows:
(i) New requirements specifying the use of certain classes of flexible hose assemblies in heated water applications, see Clause 2.3.
(ii) New requirement for an isolating valve to be installed immediately before each flexible hose assembly connected to a mixer valve or tap outlet, see Clause 10.10.2.
Notes or footnotes to tables or figures that are expressed in mandatory terms are deemed to be requirements of this document.
Notes to clauses in this document are informative only and do not include requirements.
The terms “normative” and “informative” are used in Standards to define the application of the appendices to which they apply. A “normative” appendix is an integral part of a Standard, whereas an “informative” appendix is only for information and guidance.
This document includes commentary on some of the clauses. The commentary directly follows the relevant clause, is designated by “C” preceding the clause number and is printed in italics in a box. The commentary is for information and guidance and does not form part of the document.
Originated as part of AS CS 3-1931. AS 3500.3.1:1998 and AS/NZS 3500.3.2:1998 jointly amalgamated, revised, and redesignated as AS/NZS 3500.3:2003. Previous edition 2021. Fifth edition 2025.Contents:
Section 1: Scope And General
Section 2: Materials And Products
Section 3: Cross-Connection And Backflow Prevention And Thermostatic Mixing Valves
Section 4: Installation Of Cold And Heated Water Piping And Controls
Section 5: Installation Of Water Heaters — General Requirements
Section 6: Installation Of Solar Water Heaters
Section 7: Uncontrolled Heat Sources
Section 8: Energy Efficiency
Section 9: Testing And Commissioning
Section 10: Sizing And Installation Of Circulatory Heated Water Reticulation
Appendix A: (Informative) Water Analysis
Appendix B: (Informative) Demonstrating Products And Materials Are Fit For Purpose
Appendix C: (Normative) Internal Pipe Diameters
Appendix D: (Informative) Preferred Pipe Sizes For Non-Circulatory Typical Single-Storey Household Installations
Appendix E: (Informative) Recommendations For The Installation Of Unrated Solar Heated Water Supply Systems
Appendix F: (Informative) Recommendations For The Installation Of Close-Coupled And Integral Solar Heated Water Supply Systems On Roofs
Appendix G: (Informative) Solar Heated Water Supply Systems — Suggested Component Sizes (Custom-Built Systems)
Appendix H: (Informative) Estimation Of Shading Of Collectors
Appendix I: (Informative) Effect Of Inclination And Orientation On System Performance
Appendix J: (Informative) Map Of Regional Basic Design Wind Speeds
Appendix K: (Normative) Australian Climate Regions
Appendix L: (Normative) New Zealand Climate Regions
Appendix M: (Informative) Operation And Maintenance
Appendix N: (Normative) Provision For Expansion And Contraction
Appendix O: (Informative) Estimation Of Probable Simultaneous Demand For Residential Buildings From The Total Of Loading Units
Appendix P: (Normative) Sizing Of Expansion Vessels In Mains Pressure Systems
Appendix Q: (Informative) Sizing Of Branches From Circulatory Heated Water Systems
Plumbing and Drainage.
WS-014
Association of Hydraulic Services Consultants Australia; Association of Hydraulic Services Consultants Australia (New Zealand); Australian Building Codes Board; Australian Gas Association; Australian Industry Group; Australian Stainless Steel Development Association; Australian Steel Institute; Backflow Prevention Association of Australia; Chartered Institution of Building Services Engineers ANZ; Engineers Australia; Hydraulic Consultants Association Australasia; International Copper Association Australia; Master Plumbers Australia and New Zealand; Master Plumbers, Gasfitters and Drainlayers New Zealand; Ministry of Business, Innovation and Employment (MBIE); Plastics Industry Pipe Association of Australia; Plastics New Zealand; Plumbers, Gasfitters and Drainlayers Board; Plumbing Distributors Association of New Zealand; Plumbing Products Industry Group; The Institute of Plumbing Australia; Water New Zealand; Water Services Association of Australia.
