Plumbing is invisible until it fails. Upon inspection, it’s a morass of different pipes and arachnoid fittings. Use this handy guide to avoid confusion and prevent grisly plumbing disasters.



Galvanised Steel Copper Polyvinyl Chloride (PVC) Cross-linked Polyethylene (PEX) Poly-propylene (PP)
Advantages Inexpensive, durable Lightweight, corrosion-resistant Inexpensive, lightweight, easy to use Flexible, easy to join, lower propensity to leak Durable, minimal risk of chemical exposure
Disadvantages Develops lime deposits in alkaline water Expensive, may require brazing tools, may get stolen Limited to uses that stay below 60 degrees, like drainage and wastewater Damaged by UV light Expensive, requires special tools
Joining Pipe is threaded, and joints are sealed with pipe-joint compound or tape. Copper pipe is traditionally brazed, but compression fittings create brazeless joints, though they sometimes require special tools. Cut pipe to length with a saw, then join to fittings with adhesive. Also accepts compression fittings, like copper. After a fitting has been inserted into the pipe, a special crimping tool clamps a ring around it, forming a seal. A heating tool is used to semi-liquefy the ends of the pipe to be joined. They are then hand-pressed together.




90-degree elbow 45-degree elbow tee P-trap plug
90-degree street elbow 45-degree street elbow reducing coupling wye union cap

Originally published in the November 2015 issue of Popular Mechanics. Email your shop notes to