The warranty for Dux Qest expired years ago and so has the company that sold it. We recommend you call one of our licensed plumbers to carry out a plumbing inspection to check for Dux Qest if you’re in the market for a new property.

If you’re buying a new home or investment property, get the plumbing checked. It’s better to know if the property has got Dux Qest plumbing before you sign the dotted line, so you can factor any replacement or renovation costs into the purchase price.

Contact us today to discuss replacing existing pipes or inspecting your home for Dux Qest plumbing.

Replace the old with the new

If you’ve never heard of it, all you really need to know is that Dux Qest plumbing is one product you do not want in your home. It is notorious for spontaneously failing and causing leaks.

Behind many walls and under the floors of homes and commercial properties throughout New Zealand lies a big problem: black plastic pipes that have been bursting for over 30 years. If your house of business premises has it, you need to get a plumber in to replace it.


First generation plastic piping

Dux Qest was installed with fervour in houses in the late ‘70s and ‘80s replacing copper piping. According to the government’s housing and building ministry, twenty to forty thousand homes had Dux Qest installed, and by the ‘90s it was failing around the country as it reacted with chlorine in water.

The manufacturer has changed its name and the product was withdrawn around 1987. The use of Dux Qest pre-dates the current plumbing Building Code and the Building Act.

No cover for Dux Qest plumbing

In New Zealand, most of the major insurance companies won’t cover plumbing leaks or will place restrictions on the policy if they know Dux Qest is in a house.

What is Dux Qest?

Dux Qest is a hard rubbery black piping around two centimetres in diameter. It can be difficult to distinguish from other black polybutylene plumbing. The tell-tale sign is that you can often find “Qest Dux” written in white on the pipe. However, this does rub off, so it is not always reliable way of identifying the plumbing.

Leaks and bursts

Brittle pipes leaking and fittings bursting cause floods and whole ceilings to fall through. Many leaks occur at bends or where pipes are crimped and joined by acetyl elbows and tees. Leaks also arise from the pipes splitting under tension. Leaks can go undetected for days, weeks and even years, and before you know it, walls and ceilings finally give way.

There is an increased risk of the piping leaking if it has been exposed to sunlight. The ideal exposure time for Dux Qest piping to direct sunlight is less than 30 days, including the time spent sitting in a wholesaler’s yard.

Dux Qest is particularly problematic in homes that have high water pressure. Leaks will occur after an old low-pressure hot water cylinder has been replaced with a new mains pressure cylinder which dramatically lifts the water pressure in the hot water feed.

At FlowFix, we get regular calls to fix Dux Qest leaks and to refit entire home plumbing systems.

dux qest pipe

If you are already a homeowner and have noticed areas of swollen skirting or areas of flaking paintwork or paint that has discoloured or you can smell damp, it might be time to give us a call to discuss replacing existing pipes or inspecting your home for Dux Qest plumbing.

Call Colette on 027 234 5454 or

Our plumbers can inspect your piping and provide a free quote to replace any Dux Qest piping. Yes, we appreciate it is a major job, but it is definitely a worthwhile investment. We can re-pipe your home, providing a solid guarantee on all the new piping and connections as well as a 7-point guarantee on our plumbing work.


For a free, no-obligation quote for Dux Quest plumbing checks and replacement in Warkworth, Orewa and the Hibiscus Coast, please call us on 027 265 4949.