7 Different Types of Home Plumbing Pipes and How to Choose One

PEX Pipe

• Best for: Water supply lines

PEX (cross-linked polyethylene) is a durable plastic piping that's used to supply water. It is rigid enough to withstand the pressures of water supply but flexible enough to weave throughout walls, ceilings, basements, and crawlspaces. It is also far less expensive compared to many other piping materials.

The tubes commonly come in 1/2-inch and 3/4-inch diameters, and they're easy to cut and join. Plus, they're typically color-coded red for hot water and blue for cold water.

PVC Pipe

• Best for: Drain and vent lines

PVC (polyvinyl chloride) pipe is a white plastic pipe material that's commonly used for waste lines. It initially gained popularity because it was lighter and easier to work with than traditional galvanized steel pipe. It's also inexpensive and fairly durable.

PVC pipe is moderately easy to install and requires little more than a hacksaw and a miter box to cut. It glues together with solvents.

Rigid Copper Pipe

• Best for: Water supply lines

Copper pipes are primarily pure copper as evidenced by their shiny reddish-brown appearance. Rigid copper is often used for water supply lines within the home. It is valued because it does not come with health risks unlike other pipe materials, such as plastics, that can leach chemicals.

Rigid copper also is quite durable, and it can be cut easily with a tubing cutter or hacksaw. However, it is fairly expensive.

ABS Pipe

• Best for: Drain and vent lines

ABS (acrylonitrile butadiene styrene) pipe is made of a thermoplastic resin and looks very much like PVC pipe except it is black and slightly softer. It's mainly used as a vent and drain line.

This pipe is fairly durable, though sun exposure can warp and degrade it, and it's a cost-effective choice. But like PVC, it isn't to code everywhere, so check your local regulations.

Flexi Pipe

• Best for: Connections

Flexible pipe, often called flexi for short, is flexible tubing typically made of stainless steel. It's commonly used for final piping connections to appliances, such as water heaters, toilets, and sinks. It's generally not permitted for use inside walls or floors. 

Flexi pipe comes in many lengths and sizes. It's somewhat durable, though it's not uncommon for it to fail after years of wear and tear. It also is expensive, though you typically don't need much of it for a project.

Galvanized Steel Pipe and Cast Iron

• Best for: Water supply lines, drain and vent lines

Two additional types of pipe are sometimes found in older homes and are infrequently installed, especially by DIYers: galvanized steel and cast iron pipe.

Galvanized steel is rigid, corrosion-resistant steel piping that was used for decades for drainage, water supply, gas supply, and several other purposes. While galvanized steel pipe is still around (particularly for gas supply), it is far less common and not used for water supply in new construction or remodel projects. While it has good durability, it's also pricey to install. Each end of the pipe is threaded, and individual pipes are screwed into each other with connecting fittings.

Cast iron is rigid, dark gray piping that was often used for sewer and other drainage purposes. It is still found in many homes and is used today in some commercial and high-rise building applications. Cast iron is expensive but durable with good longevity. It's viable until the point that it rusts completely through. It's also very heavy and difficult to cut. Retrofits tend to replace cast iron pipe with rigid plastic pipes, such as ABS.