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

Main Types of Residential Plumbing Pipes

The Spruce / Michela Buttignol

There are several common types of home plumbing pipes used to carry water to and away from fixtures and appliances. And regardless of whether you're hiring a plumber or taking on a DIY home plumbing project, the experience can be confusing because of all the pipe material options.

What's the right pipe for water supply, drainage, sewer, and even the exterior? The answer is not as clear as it was in the past when the main pipe choices were just galvanized steel or cast iron. Below, we'll break down common pipe materials to help you choose which is best for your space and application.

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.

Tip

Check your local codes before installing PEX pipe. While it is commonly used across the United States, it is not permitted everywhere. It must be well supported, and the fittings must be installed properly and tested, especially when installed behind walls.

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.

Tip

Like PEX pipe, PVC pipe is not permitted everywhere. So check your local regulations before installing.

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Watch Now: Best Ways to Repair a Leaky PVC Pipe

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.

Tip

Among the multiple options for connections, the best is the solder-type connection. The solder connection requires experience coupled with safety protocols.

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.

Choosing Plumbing Pipes

When choosing the right pipe for your plumbing job, the most important factors to consider are both the function the pipe needs to perform as well as the layout of the space you're working with. For instance, you might need a more flexible pipe for tight areas.

Cost also will be a factor in your decision. In general, a perk of more expensive piping is it tends to last longer. So ultimately you might save money in the long run. Plus, you'll have to know your local building codes to make sure you're using a permitted type of piping.

Speaking with a contractor or other plumbing expert can help you make an informed decision for your project. Sometimes you might not know exactly what you'll need until walls come down and you see the space you're working with.

FAQ
  • What is the most common pipe used in houses?

    Copper and PEX are the most common pipe materials used in homes. Copper pipes are durable, corrosion-resistant, and can be used for hot and cold water. PEX seems to be replacing copper pipes at a high rate since it is less expensive, more flexible, and easier to install.

  • What are the different types of water plumbing systems in a home?

    Plumbing piping is used for three primary reasons: toilet sewage, stormwater drainage, and drinking water. In each case, these systems bring and remove water into and from the home.

  • What is the safest type of pipe for drinking water?

    According to the Environmental Working Group, copper pipes with lead-free joint materials are the best choice for water pipes. They are long-lasting and won't leach chemicals into your drinking water. The group also cites polypropylene (PEX) pipes as a suitable alternative to copper that is less likely to leach chemicals into the water than other types of plastic piping.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Plumbing and Pipes: Healthier Choices. Environmental Working Group.

  2. Plumbing and pipes. Environmental Working Group.