glossary Glossary 1 min read

Tempering valve

A tempering valve blends hot and cold water to limit the outlet temperature to 50°C at sanitary fixtures. Required under AS/NZS 3500.4 on residential builds.

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A tempering valve (also called a thermostatic mixing valve or TMV) is a plumbing device that blends hot and cold water to deliver a safe mixed temperature at sanitary fixtures. Under AS/NZS 3500.4:2025, all fixtures used primarily for personal hygiene (showers, baths, basins) must be supplied through a tempering valve set to a maximum of 50 degrees Celsius at the outlet. The storage system is kept at 60 degrees Celsius or above to suppress Legionella; the valve blends down to the safe delivery temperature. Complying devices must meet AS 4032.2.

Also known as: TMV, thermostatic mixing valve, hot water tempering valve

Category: Plumbing compliance

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Last updated: 2026-05-08. Verified: 2026-05-08.