mdpe pipe is the one you normally pick for underground water supply when you want coil form rather than rigid lengths. Size is the main call. Smaller mdpe pipe suits domestic service work. Larger diameters are there when the flow demand or main run calls for it. Blue pipe is the common choice for potable supply, and the wrong size is what usually causes grief later, not the material itself.
Polyplumb MDPE Adaptor
MDPE riser sealing ring adaptor, 355 x 7mm, black
Plasson 45° Elbow - 63mm x 63mm
45° compression elbow for 63mm MDPE water pipes
John Guest Speedfit MDPE Equal Tee - 25mm
John Guest Speedfit 25mm MDPE equal tee for water distribution branch connection…
Polypipe Polyfast 90° Elbow - 63mm
63mm MDPE 90° elbow for potable water systems
Plasson Pushfit Female Adaptor - 25mm x 3/4"
Pushfit female adaptor, black and grey, 19.05mm (3/4") size.
Polypipe Polyfast End Plug - 20mm
20mm acetal end plug for Polyfast potable water pipe
Plasson Pipe Liner - 50mm
50mm pipe liner for PE SDR 11 pipe, 16 bar rated
Polypipe MDPE Polyfast Adaptor Cold Water Only - 22mm x 32mm
MDPE push-fit adaptor for cold water, 22mm x 32mm
JG Speedfit MDPE Wall Plate Elbow - 25mm x 1/2"
JG Speedfit MDPE wall plate elbow, 25mm x 1/2 inch
Plasson Elbow Female Offtake - 25mm x 3/4"
90° elbow for 25mm MDPE to 3/4" imperial, WRAS approved
Start with the space you’ve got and how hard the line is working, then the rest falls into place. A short run with tight bends and a straightforward feed usually points you one way. A longer service run, or a job with more demand, pushes you up a size. That’s where mdpe pipe 25mm, 32mm, 50mm and 63mm stop being just numbers and start being about flow, handling and the room you have to work with. Then it comes down to form. A mdpe pipe roll is easier to pull through awkward routes, while a straighter length can sit cleaner where the layout is open.
If you’re choosing mdpe pipe, start with coils or straights. A mdpe pipe roll suits longer runs and keeps the number of joints down, so it’s the one you reach for on service work where you want a continuous line.
Straight mdpe pipes make more sense where the run is broken up or access is tighter. They’re easier to handle in shorter lengths, but you’ll make more joints.
25mm is the lighter-duty choice for smaller supplies. mdpe pipe 32mm gives you a bit more capacity without moving into the larger sizes.
50mm and mdpe pipe 63mm sit at the heavier end of the range. They suit higher demand or main runs, but they’re less forgiving to handle and route.
The first check is what the line needs to do and how you’re running it. For a straightforward underground service, mdpe pipe is usually the one you reach for.
Size still matters. 25mm is common where demand is modest. 32mm gives you more headroom. 50mm or 63mm suits longer runs or a supply that needs more capacity.
Rolls work well on continuous runs because they cut down on joints. Straight lengths can be easier where the route is broken up or access is tight.
If you’re tying into other plumbing work, check the next stage against Waste Pipe & Fittings and Access Panels before you order.
Once you’ve settled the mdpe pipe, the next call is what the run has to pass through and finish against. Access panels matter where you need future access without tearing out finishes. Waste pipe and fittings come in when the job moves from the supply line into internal drainage.
That’s the bit that gets missed on site. The pipe is only half the job if you haven’t allowed for access, terminations and the surrounding finish. Keep the surrounding spec tight and you avoid coming back to alter a wall or chase because the wrong piece was left out.










