StandAId › NCC explained › Maximum hot water temperature at the tap: what the Plumbing Code requires
Two temperatures matter in a domestic hot water system and they pull in opposite directions. Water has to be stored hot enough to control Legionella, but delivered cool enough at a bath, basin or shower that a child or elderly person can't be scalded. The NCC's Plumbing Code handles that with a maximum delivery temperature at fixtures used for personal hygiene, and a storage temperature requirement on the heater side.
The usual way to satisfy both is a tempering valve or thermostatic mixing valve on the outlet side of the heater, with the deemed-to-satisfy detail coming from AS/NZS 3500.4.
The clauses below are the Volume Three heated water provisions.
This page is a plain-English guide written by StandAId, followed by the actual NCC 2025 clause text. It is not professional advice and StandAId is not endorsed by the ABCB — always check the current edition on ncc.abcb.gov.au and your state's requirements.
(1) A heated water service must be connected to a drinking water supply.
Application: B2P1 applies to a heated water service used for human consumption, food preparation, food utensil washing or personal hygiene.
(1) In a new Class 1 or Class 10 building, a water heater in a heated water supply system must be—
(a) a solar water heater complying with (2); or
(b) a heat pump water heater complying with (2); or
(c) a gas water heater complying with (3); or
(d) an electric resistance water heater only in the circumstances described in (4); or
(e) a wood fired thermosiphon water heater or direct fired water heater each complying with AS/NZS 3500.4.
(2) In a new Class 1 or Class 10 building a solar water heater and a heat pump water heater must comply with either—
(a) Table B2D2a, for the minimum Small-scale Technology Certificates for the installation zone; or
(b) Table B2D2b, for the minimum energy savings calculated in accordance with AS/NZS 4234.
(3) In a new Class 1 or Class 10 building, a gas water heater must be rated not less than 5 Stars in accordance with AS 4552.
(4) In a new Class 1 or Class 10 building, an electric resistance water heater with no storage or a heated water delivery of not more than 50 litres in accordance with AS 1056.1 may be installed when—
(a) the building has—
(i) not more than 1 bedroom; and
(ii) not more than 1 electric resistance water heater installed; or
(b) the building has—
(i) a water heater that complies with (2) or (3); and
(ii) not more than 1 electric resistance water heater installed; or
(c) the greenhouse gas emission intensity of the public electricity supply is low.
[See Table B2D2a — Minimum Small Scale Technology Certificates]
[See Table B2D2b — Minimum energy savings]
Limitation: B2D2 does not apply where compliance with H6P2 of Volume Two is achieved by complying with S42C3 using house energy rating software and S42C4(2).
| Number of bedrooms | Minimum energy saving |
|---|---|
| 1 or 2 | 40% for a ‘small load’ system |
| 2 or 3 | 60% for a ‘medium load’ system |
| 4 or more | 60% for a ‘large load’ system |
| Number of bedrooms in the building | 2025 | 2026 | 2027 | 2028 |
|---|---|---|---|---|
| 1 or 2 | 8 | 7 | 5 | 4 |
| 3 or 4 | 13 | 11 | 8 | 6 |
| 4 or more | 16 | 14 | 11 | 8 |
State variation: this clause is varied in New South Wales, Queensland, South Australia, Tasmania. Check the state schedule on the ABCB site, or set your state in StandAId to get the right version.
(1) The delivery temperature of heated water at the outlet of each sanitary fixture must be—
(a) not more than 45 °C in any—
(i) residential part of an aged care building; or
(ii) patient care area in a health-care building; or
(iii) part of an early childhood centre, or primary or secondary school, that is used by children; or
(iv) designated accessible facility in a common area of a Class 2 building, or in any part of a Class 3 or Class 5 to Class 10 building; or
(b) not more than 50 °C in all other cases.
Application: B2D5 applies to all heated water installations intended for personal hygiene.
Explanatory information: Scenarios covered in B2D5 may include where— • a heated water service is installed on the premises for the first time; or • the water heater forming part of an existing heated water service is— • replaced with a like-for-like water heater; or • replaced with a different type of water heater; or • relocated, and is reconnected to, some or all of the sanitary fixtures to which it was previously connected; or • more than one existing sanitary fixture is replaced with new similar fixtures; or • an existing heated water service on the premises is altered or extended to serve additional sanitary fixtures. Consideration should be given to the intended occupants of a building when commissioning the heated water delivery temperature. For example, if the occupants of a Class 1 building are older adults or young children, a lower temperature than specified in B2D5(b) should be considered.
State variation: this clause is varied in New South Wales, South Australia, Western Australia. Check the state schedule on the ABCB site, or set your state in StandAId to get the right version.
(1) Compliance with B2P6 is verified for each heated water storage system when the water heater is designed such that all water is subjected to a temperature-dependent minimum exposure period as specified in Table B2V1 within 7 days before passing through the water-heating appliance's heated water outlet.
[See Table B2V1 — Heated water storage minimum exposure period]
| Temperature | Minimum exposure period |
|---|---|
| 70 °C or greater | 1 second |
| 66 °C | 2 minutes |
| 60 °C | 32 minutes |
Got a follow-up? StandAId answers questions on the text of the NCC 2025 — Volumes One, Two, Three and the Housing Provisions — with the clause linked. Free account, 3 questions a day; upload your own standards for more.
Ask the NCC in StandAId — free, 3 questions a dayNCC Volume Three sets a maximum delivery temperature at sanitary fixtures used primarily for personal hygiene — 50°C in a typical house, with a lower figure for certain care facilities. See B2D5.
Storage temperature is about controlling Legionella growth in the tank; delivery temperature is about scalding. A tempering or thermostatic mixing valve reconciles the two. See B2D2 and B2V1.
The National Construction Code 2025 was provided by the Australian Building Codes Board under the CC BY 4.0 licence. © Commonwealth of Australia and the States and Territories of Australia 2026, published by the Australian Building Codes Board. Licence: CC BY 4.0. NCC text on this page was extracted from the ABCB's NCC 2025 dataset (v1.2) and reformatted; figures, diagrams and photographs are not reproduced (they are outside the licence) — follow the links to view them on the ABCB site. The ABCB publishes the NCC without warranty and it is not legal or professional advice.
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