What Does DZR Mean - and Why Does It Matter for Your Tapware?

Monday 08 June 2026

If you have been shopping for tapware recently, talking to a plumber, or working through a building consent application, there is a good chance you have come across the letters DZR. They appear on product packaging, in specification sheets, and increasingly in conversations between suppliers, installers and architects.

But what does DZR actually mean? And why does it now matter so much for tapware in New Zealand?

This post answers both questions - in plain language, without the jargon.

First, a quick primer on brass

Most tapware is made from brass - a metal alloy composed primarily of copper and zinc. Brass has been used in plumbing for generations because it is strong, workable, and naturally resistant to corrosion. It’s also relatively affordable to manufacture into the precise shapes that taps, mixers and valves require.

The problem is that not all brass behaves the same way over time, particularly when it is in constant contact with pressurised water.

What is dezincification - and why does it matter?

Here is the analogy that makes it click: imagine a chocolate-covered honeycomb bar. The chocolate is the copper in the brass; the honeycomb is the zinc. Over time, in certain water conditions, particularly where the water is soft, warm, or slightly acidic, the zinc can begin to leach out of the brass, leaving behind a weakened, porous copper structure. The honeycomb is gone. What remains looks intact on the outside but has lost most of its structural integrity.

This process is called dezincification. And in plumbing, the consequences are not abstract. A brass component that has undergone dezincification can:

Develop pinhole leaks or sudden failures
Allow contaminants to enter the potable water supply through that porous structure
Seize or crack under pressure
Fail inspection or trigger a costly replacement mid-project

In a domestic setting, a dezincified mixer tap might fail after a few years rather than lasting decades. In a commercial building - a hotel, a hospital, a multi-storey apartment block - the scale of the problem multiplies considerably. You are not dealing with one faulty tap; you could be looking at systemic failures across an entire water system.

So what is DZR brass?

DZR stands for dezincification-resistant. DZR brass is a specific formulation of brass alloy that includes a small amount of arsenic (typically around 0.02–0.06%), which inhibits the dezincification process. The zinc stays put. The structural integrity of the component is maintained over the long term, even in challenging water conditions.

It’s not a coating or a treatment applied after the fact; it is a property of the metal itself. A DZR brass component is resistant to dezincification throughout its entire structure, not just at the surface.

For anything in constant contact with pressurised drinking water - mixer valves, tapware bodies, angle stops, pressure-reducing valves - DZR brass is now the required standard in New Zealand.

Why is DZR now required under the New Zealand Building Code?

From 2 May 2026, G12/AS1 Amendment 14 became the only MBIE Acceptable Solution for new building consent applications under Building Code Clause G12 (Water Supplies). One of its two core requirements is that any copper alloy component in contact with drinking water and subject to hydrostatic pressure must be made from dezincification-resistant copper alloy.

The intent is straightforward: to protect the long-term integrity of New Zealand's potable water infrastructure, and to ensure that the products going into new homes and buildings today will still be performing safely in 20 or 30 years' time.

James Robertson, General Manager, Distribution at Robertson Bathware, has seen the industry work through these changes up close. "The requirement for DZR brass is not a surprise to anyone who has been paying attention to where plumbing standards have been heading globally," he says. "Europe moved in this direction years ago. New Zealand has essentially caught up with best practice. The products that Robertson specifies from our European manufacturing partners were already built to these standards, so for us and our customers, the transition has been seamless."

You can read more about James and the Robertson team at robertson.co.nz/our-people.

What does and doesn't need to be DZR compliant?

This is where some confusion has crept into the market, so it’s worth being precise.

Products that must comply with the DZR requirement include any copper alloy component in contact with potable water that is subject to hydrostatic pressure. In practice, this covers:

Kitchen mixers and basin mixers
Mixer valves and thermostatic valves
Tapware bodies and cartridge housings
Angle stops and isolation valves
Pressure-reducing valves and water meters
Pipe fittings made from copper alloy

Products that are not subject to the DZR requirement include:

Shower heads (not under hydrostatic pressure)
Open bath spouts (not under hydrostatic pressure)
Toilets, baths, urinals and laundry appliances
Irrigation systems and fire protection systems

The distinction comes down to hydrostatic pressure. If a component sits in the pressurised water system, with water constantly bearing against it, it needs to be DZR compliant. If it is simply at the outlet end where water flows freely, it falls outside the requirement.

"The question we get asked most often is about shower heads," says James Robertson. "People assume that because they are part of the shower system, they must need to comply. But the DZR requirement is specifically about components under pressure. The shower head itself is at the outlet; it isn’t holding back pressurised water. The shower mixer valve, on the other hand, is a different matter entirely."

What does DZR certification actually look like?

Knowing a product needs to be DZR compliant is one thing. Being able to verify that it is, on-site, during specification, or at inspection is another.

Here is what to look for:

The DR marking. Compliant products will carry a DR marking on the product itself or its packaging. This indicates dezincification resistance to the relevant standard. Alongside this, products should also carry an LF marking (for lead-free), as Amendment 14 mandates both.

A Supplier's Declaration of Compliance (SDoc). This is the primary documentation that evidences compliance. An SDoc confirms that the product meets the requirements of G12/AS1 Amendment 14. For building consent applications, project records, or inspection queries, this is the document you need. Any reputable supplier should be able to provide this promptly.

Recognised international certification markings. Products that carry internationally recognised certification (such as WRAS in the UK or equivalent European standards) will generally already meet or exceed the New Zealand requirements for DZR compliance.

If you are a plumber and a product arrives on-site without clear markings or documentation, the responsible course is to query it with your supplier before installing. MBIE is clear that plumbing professionals bear responsibility for ensuring the products they install comply with the Building Code at the time of installation.

How to confirm DZR compliance before you buy or specify

Whether you are a homeowner choosing tapware for a bathroom renovation, or a plumber about to start a new install, the process for confirming compliance is the same:

Check for DR and LF markings on the product or its packaging
Ask your supplier for the SDoc - a compliant supplier will have this ready
Check the product listing - Robertson product pages clearly indicate compliance status
If in doubt, ask - your Robertson representative can provide documentation for any product in the current range

Robertson Bathware's DZR compliant tapware range

Robertson Bathware began working with its European manufacturing partners on compliance well before the Amendment 14 deadline. The result is a current tapware range where every single product is both lead-free and DZR compliant, with no exceptions, no products to phase out, and no uncertainty for customers.

"We made a deliberate decision to get ahead of this," says James Robertson. "Our job is to make compliance easy for the people who specify and install our products. If we had been scrambling to update our range after the deadline, we would have been letting them down. That is not how Robertson operates."

The range includes basin mixers across all configurations - 1, 2 and 3 tap hole, wall-mounted, extended height and freestanding - as well as kitchen mixers, shower mixers, thermostatic valves, sensor mixers and healthcare products. Premium brands including Zucchetti and Elementi are represented throughout, delivering design quality alongside complete compliance.

If you need compliance documentation for a specific Robertson product, our team can provide it quickly. Contact your Robertson representative or reach out directly through the website.

Shop DZR compliant tapware from Robertson →

Quick reference: DZR essentials

Question	Answer
What does DZR stand for?	Dezincification-resistant
What is dezincification?	The leaching of zinc from brass, leaving a weakened, porous structure
When did DZR become mandatory in NZ?	2 May 2026, under G12/AS1 Amendment 14
Which products need to comply?	All copper alloy components in contact with potable water under hydrostatic pressure
Which products are exempt?	Shower heads, open bath spouts, toilets, baths, irrigation systems
How do I check compliance?	Look for DR and LF markings; request an SDoc from your supplier
Is Robertson tapware DZR compliant?	Yes, every product in the current Robertson tapware range

Robertson Bathware has supplied quality tapware to New Zealand homes and projects for over 40 years. Our current tapware range is fully compliant with G12/AS1 Amendment 14 - lead-free, DZR brass, and ready to install. For compliance documentation or to discuss your project, contact our team or speak to your regional Robertson representative.