What is a Tempering Valve and Why is it Legally Required?

If you've ever had a plumber mention installing a "tempering valve" during your hot water system replacement, you might have wondered what this mysterious device actually does. More importantly, why is it legally required in Australia? Let's break down this essential safety feature that's quietly protecting households across the country.

What Exactly is a Tempering Valve?

Think of a tempering valve as your home's personal water temperature manager. It's a clever plumbing device that sits between your hot water storage tank and your taps, mixing hot and cold water to deliver water at a safe, consistent temperature - typically set around 50°C.

• Safety first - prevents scalding injuries from water that's too hot
• Bacteria control - allows your hot water tank to stay at 60°C to kill harmful Legionella bacteria
• Consistent comfort - delivers water at the perfect temperature every time

The Legal Requirement Explained

In Australia, tempering valves aren't just a good idea - they're the law. Under the Australian/New Zealand Plumbing Code (AS/NZS 3500), all new and replacement domestic hot water systems must have tempering valves installed by licensed plumbers.

Here's why this legal requirement exists:

• Scald prevention - Water above 50°C can cause serious burns in seconds, especially for children and elderly family members
• Public safety - The regulations ensure consistent protection across all Australian homes
• Professional installation - Only licensed plumbers can install and adjust these valves to maintain compliance

How It Works in Your Home

Your hot water system needs to store water at 60°C to prevent dangerous bacteria growth, but that temperature is too hot for direct use. The tempering valve solves this by:

• Taking hot water from your storage tank (60°C)
• Mixing it with cold water in precise proportions
• Delivering perfectly tempered water at 50°C to your showers and bathroom taps

This clever balancing act means your system stays hygienic while your family stays safe from accidental burns.

When You Need a Tempering Valve

You'll need a tempering valve installed in these situations:

• New hot water system installation
• Replacing an existing hot water system
• Bathroom renovations that involve plumbing work

Remember: kitchen and laundry sinks are exempt from the 50°C limit, as higher temperatures are sometimes needed for cleaning purposes.

What About Thermostatic Mixing Valves?

For high-risk environments like nursing homes, childcare centres, and hospitals, you might hear about thermostatic mixing valves (TMVs). These are more advanced versions that offer finer temperature control and are required in situations where vulnerable people use the facilities.

Final Takeaway

That small tempering valve your plumber installs is more than just another plumbing part - it's a legally required safety device that protects your family from serious burns while keeping your hot water system hygienic. Next time you're updating your hot water system, you can feel confident knowing this mandatory addition is there to keep everyone safe in the shower.