If you have searched “what does Dux Quest look like”, you have probably just found a black or grey plastic pipe under your house and want to know if it is the one people warn about. These are photos from West Harbour homes we have been called to, and what each one tells you.
West Harbour has a lot of it. Since mid-2023 we have repaired Dux Quest at seven different West Harbour addresses, and two of those houses called us back within weeks for a second burst. That pattern is the most useful thing to understand about this pipe, so it gets its own section below.
What Dux Quest looks like in a ceiling
The photo at the top of this page is the first thing we saw at one of those homes: a hole cut in the ceiling, two runs of dark grey pipe, and water beading on the outside of one of them. The pipe is about the thickness of a finger, 15 to 16mm across. It is flexible plastic, not metal, so it sags and curves between clips where copper would run straight.
The colour varies more than people expect. Dux Quest was supplied in black and in grey, and after forty years in a ceiling space the grey often looks charcoal. The reliable check is not the colour. It is the name printed along the side of the pipe, which you can usually find if you follow a run with a torch.
What it looks like under the floor
Black Dux Quest under the floor of a West Harbour home, leaking at the joint. The brown stain on the insulation is where the water had been running.
Under the house is where most owners first see it. In the photo above the pipe is black, it runs just below the floor insulation, and the failure is at a joint fitting rather than in the middle of the pipe. That is common. The fittings on this system are a weak point in their own right, and chlorine in the town supply works on them and on the pipe over decades until neither can flex under pressure.
Look for:
- Black or grey plastic pipe, roughly finger-thick, often in long curving runs
- The Dux name printed along it, every so often
- Plastic joint fittings rather than the copper crimp joiners used on modern pipe
- Water staining on insulation or timber next to a joint, which means it has already started
If what you have found is cream, white or a lighter grey with a newer printed name on it, it may be a modern replacement pipe instead. If you are not sure, a photo of the printing is usually enough for us to tell you.
Why the second burst follows the first
At one West Harbour home the ceiling went in late November. We cut out the failed section and replaced it. At the end of January the same house called again: this time the leak was inside a wall.
At another, the first failure was under the floor beneath the hot water cylinder in early February. About five weeks later it was in the ceiling beside the shower. A third family had theirs go under the subfloor on Christmas Eve.
None of that is bad luck. Every metre of Dux Quest in a house is the same age and has had the same water through it, so when one section fails, the rest is close behind. Turning the water back on after a repair also puts a pressure surge through pipe that has lost its flex, which is why the next failure often comes in weeks rather than years. We go into the full reasons, and what it means for insurance, in our main Dux Quest guide.
What a repaired section looks like
A repaired section in the same West Harbour ceiling. The lighter grey pipe is new; it joins the old dark Dux Quest with copper crimp joiners.
This is what a repair looks like once it is done: the failed length is cut out and a new section is joined in with copper crimp joiners. It stops tonight’s leak properly. What it cannot do is change the age of the pipe on either side of it, which is why we say on every one of these invoices that the rest of the house is still plumbed in the same pipe.
Common questions
Is the black pipe under my house Dux Quest?
It might be. Black plastic pipe under a house built or re-plumbed in the 1980s is a strong sign, but check for the printed name before assuming. Grey runs can be Dux Quest too.
How do I tell Dux Quest from modern plastic pipe?
Read the printing on the pipe and look at the joints. Dux Quest joins with plastic (acetal) fittings; modern systems use crimped metal joiners and print a current brand name along the pipe.
Does Dux Quest leak slowly before it bursts?
Usually not. It tends to split or let go at a joint with no warning stage. A house that has never leaked is not a safe house, just one where the first failure has not happened yet.
How much does it cost to replace Dux Quest?
It depends on how many bathrooms there are, whether the pipe runs through walls or only under the floor, and how much lining has to come off. Staging the work, starting with the hot lines and the cylinder cupboard, can spread the cost. Our rates page shows how we charge, and we can quote once we have seen the house.
Should I fix the burst or replace the whole system?
Fix the burst so the house is usable, then plan the replacement. Repeated repairs on the same house are how owners end up with water through two ceilings in one summer. Our re-piping guide covers how that is done.
Related reading
- Dux Quest: why the same house keeps flooding, and when insurance stops paying
- Re-piping a house: when repairs have stopped being the answer
- How plumbers find a hidden leak
- Is your leak covered? The insurance mistake to avoid
- A pipe has burst: what to do in the first ten minutes
- West Harbour: sewage in the driveway, and the shared chamber underneath it
We are in West Harbour most weeks. If you have found pipe like this or water is coming through a ceiling now, our leak detection service finds the failure and we will tell you straight whether repairing it again makes sense. Call 021 837 775.