PPR or PVC: which pipe goes where in your house
Most articles on this are written by people who sell one of the two pipes, so they declare a winner. A house needs both. PPR belongs on the lines that carry water in, and especially hot water. PVC belongs on the lines that carry water away.
If you are re-piping or adding a line, our water line installation and repair service is where that work happens. This page is the background you need to follow what a plumber proposes.
The two pipes in one paragraph each
PPR, polypropylene
A thick-walled pipe, usually green or white, made for water supply. Its joints are fused: the pipe and fitting are heated on a tool and pushed together so they become one piece. It handles hot water at around 80 degrees Celsius.
PVC, polyvinyl chloride
Lighter and easy to work. It is used for cold water and, in far larger sizes, for drainage and sewage. It is not made for hot water.
Which line takes which pipe
- Hot water from a heater: PPR. This is the one line where the choice matters most, and the reason a multipoint water heater usually means new PPR to each outlet.
- Cold water supply inside the house: either works. PPR is the stronger pipe and its fused joints do not rely on glue. PVC is common on cold lines and does the job when it is installed well.
- Drains, the toilet line and vents: PVC. Drainage runs at large diameters and no pressure, which is the work PVC is made for.
- Old G.I. pipe: galvanised iron rusts from the inside over the years. If yours is running rusty, it is usually replaced in PPR.
What the joints mean for a repair
Drag the drawing sideways to see all of it.
Because PPR joints are fused, a leak in a PPR line is not fixed with tape and glue. The damaged piece is cut out and a new section fused in, which needs the heating tool. A PVC repair is simpler to do, and also easier to do badly.
Where an old pipe meets a new one, the two are joined through a threaded adaptor. That joint is worth a look whenever a leak appears near it.
When to change what you have
You do not need to re-pipe a house because PPR exists. Change a line when it is failing: rusty water, a section that keeps leaking, or pressure that has dropped because an old pipe has narrowed inside. And during a renovation, when the walls are open anyway and the cost of reaching the pipes is already paid.
Questions about PPR and PVC
- Is PPR better than PVC?
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For water supply, and above all for hot water, PPR is the better pipe. For drainage, PVC is the normal choice and PPR is not used. Most houses end up with both, each on the lines it suits.
- Can I connect PPR to my old PVC or G.I. pipe?
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Yes, through a threaded adaptor at the joint. What does not work is gluing PPR the way you would glue PVC. PPR joints are fused with a heated tool, so a repair needs that tool.
- Do I need to replace all my pipes at once?
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No. Most re-piping is done line by line, starting with whatever is failing: an old G.I. supply that runs rusty, or a section that keeps leaking. A renovation is a good moment to do more, because the walls are already open.
- Can PVC carry hot water from a heater?
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It should not. PVC is a cold water and drainage pipe and is not made for the heat. The line from a heater should be PPR.
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