MDPE pipe
In plumbing
Medium-density polyethylene pipe, the flexible plastic pipe commonly used for underground cold water supplies. Blue MDPE carries drinking water. It is laid deep enough to protect it from frost and damage, and it is joined with fittings designed for it rather than those meant for indoor pipework.
Using MDPE pipe in a plumbing system
Updated
A distinction worth remembering
Water temperature, pressure, water quality, exposure and the jointing system affect material selection. A pipe's outside diameter alone does not prove compatibility with a fitting. Use the maker's specification for the complete system and learn to recognise markings before practising selection questions.
Questions to take further
- Can any plastic pipe and push-fit fitting be mixed?
- No. Compatibility depends on the system and the manufacturer's requirements, including pipe dimensions and support inserts where specified. Similar appearance is not evidence of compatibility.
Sources
- Skills England: plumbing and domestic heating technician — The systems, materials, planning and customer responsibilities in the England occupational standard.
Where MDPE pipe fits in the learning path
The Pipework & Jointing section covers these topics:
- Pipe Materials
- Pipe Joints and Fixings
Read, practise, return
1. Read it in context
- Pipe MaterialsPipework & Jointing
- The Incoming Water SupplyCold Water Basics
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Recall a related term
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The pipe that carries mains water from the boundary of a property, usually from the outside stop tap, into the building. The property owner is normally responsible for it, and the water supplier for the pipe from the main up to the boundary. Who looks after which length can differ by nation and supplier, so it is worth checking locally.
Supply pipe
Read the Supply pipe entryCompare related terms
Open a meaning to compare its role with MDPE pipe, or follow its full entry.
Supply pipe
The pipe that carries mains water from the boundary of a property, usually from the outside stop tap, into the building. The property owner is normally responsible for it, and the water supplier for the pipe from the main up to the boundary. Who looks after which length can differ by nation and supplier, so it is worth checking locally.
Read the Supply pipe entryBefore you start: some plumbing work is regulated or notifiable
Some water fittings work needs notice to, and consent from, the water supplier before it starts. Check the rules where you live.
Gas work is for competent workers covered by a Gas Safe registered business in Great Britain. Northern Ireland has separate gas regulations. Do not work on gas pipes or appliances yourself.
In England, installing an unvented hot-water system over 15 litres is notifiable building work: use a competent installer registered with a competent-person scheme, or tell building control before work starts. Leave this work to a suitably skilled person.
Wales, Scotland and Northern Ireland have their own water and building rules; check which apply before work starts. Electrical connections belong with an electrician.
This guide does not qualify you or make you competent, approved or registered for plumbing, gas or unvented work.
A definition is a start. Using it in a real question is where it sticks.