HOT WATER COMPLIANCE
Hot water temperature rules: stored hot, delivered safe
Hot water in Victoria follows one rule that surprises people: it is stored hotter than it comes out of the tap. The storage temperature keeps the water safe from bacteria, and a valve brings the delivered temperature down so it is safe from scalds. Here is how it works.
Stored hot, delivered cooler
Stored hot water is kept hot, commonly at 60°C or above, to suppress the bacteria that can grow in warm water. That temperature is too hot to deliver to a tap safely, so a tempering or mixing valve blends it down before it reaches the outlet. Two numbers, two jobs: storage for safety from bacteria, delivery for safety from scalds.
The 50 degree delivery limit
For ordinary domestic outlets, delivered hot water is limited to a maximum of 50°C at the fixture. In higher-risk settings, like healthcare, aged care, and early-childhood facilities, the limit is lower again and a thermostatic mixing valve is required to hold it tightly. The delivered temperature, not the storage temperature, is the one a scald risk turns on.
How the limit is met
A tempering valve or thermostatic mixing valve on the hot water outlet does the blending. The device has to suit the setting and be set correctly, and the delivered temperature is checked at the fixture when the system is commissioned. See the difference between the two devices in the TMV versus tempering valve guide.
What to record
At commissioning, measure the delivered temperature at the fixture and record it, with the valve and its setting in shot. A dated reading at or below the limit is the cleanest proof the system was handed over safe. Elemetric captures that as part of the hot water job. See also commissioning, the final checks.
Common questions
What temperature should hot water be delivered at?
For ordinary domestic outlets, a maximum of 50°C at the fixture. Higher-risk settings such as healthcare and aged care require a lower limit and a thermostatic mixing valve.
Why is stored hot water kept at 60 degrees if the tap limit is 50?
Storing at 60°C or above suppresses bacteria such as Legionella. A tempering or mixing valve then blends the water down to a safe delivery temperature at the outlet.
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Download on the App Store →General information for licensed tradespeople, not legal or regulatory advice. The licensed plumber remains solely responsible for compliance. Refer to the current AS/NZS 3500 standards and the Building and Plumbing Commission (formerly the VBA) for authoritative requirements.