In basic plumbing, there are three different kinds of plumbing pipes. To most homeowners, it can be confusing and a bit daunting when you go down to the basement or other locations in the house. It is not always clear what each of the pipes are used for and why they are located in that specific location.

There are waste pipes that lead wastewater out of the house, vent pipes that are tied to the waste system that provide air to the waste system to lead odor out of the house, and water pipes that lead fresh water into the house. There are also pipes that convey gas and heating to the house.

For a homeowner, the number one thing to know is where the water main shutoff valve is to the house because if suddenly something goes wrong and the shutoff valve is open, there will be gushing water making a large mess before there is a chance to call a professional plumber for help.

Often, there are more shutoffs than just the main water main. In many cases, there are individual water shutoffs for each individual fixture, but when in a rush and there is flowing water, sometimes it makes sense to know where the main shutoff is and to go turn it off.

To add to the confusion, the types of pipes used have changed over the years as there has been improved technology and better manufacturing techniques.

Waste and Vent Plumbing Pipes

On the waste and vent side of plumbing pipes, those pipes have been traditionally made of cast iron, with some of the pipes occasionally being made of galvanized steel. The cast iron pipes are large, thick, dark metal-looking pipes that you see in the basement.

One of the big changes over recent years is that plumbers can use a plastic version of those pipes. In the plumbing industry, they have to verify what ingredients are safe to use in those plastic pipes, so when professional plumbers use a plastic pipe or fitting, each pipe will have a designation number stamped on it that will assure that it has met certain standards.

It is an American Society for Testing and Materials (ASTM) verified number, so plumbers cannot use any plastic pipe or fitting; it must have been tested and approved for that use. Within those plastic waste and vent pipe choices, there are two basic kinds.

There is a white plastic version called Polyvinyl Chloride (PVC), and the C stands for a type of chloride, so those pipes are grouped into a family of pipes made of chlorides.

There is also a black plastic version where every pipe and fitting looks identical if you hold the pipes and fittings side by side, but it will be black called Acrylonitrile Butadiene Styrene (ABS), and those contain a type of butyl.

Both types of plastic piping are up to code in almost all plumbing codes that St Paul Pipeworks plumbing professionals are proficient in.

When installing plastic waste and vent piping, a few things are different from installing metal piping. Plumbers have to support plastic piping more often so it does not sag due to the weight of the water.

The plastic also needs to be installed in an area without exposure to any ultraviolet lighting. Also, there are sometimes smaller clear tubing lines used to convey condensate from furnaces or air conditioners made of plastic.

Water Pipes

On the water side of plumbing, in the pipes that convey water throughout the home, there was still a fair amount of pipe carrying water made of lead at the turn of the century. Most of that lead pipe has been taken out of service now.

There are potential health hazards with lead piping. The most significant risk from lead is to infants, young children, and pregnant women. In most of the remaining homes containing lead pipes, the pipes have eventually gotten so coated with scale on the inside of the pipe that the coating has insulated the pipe, and health hazards are unlikely.

But gradually, over time, all water utilities have programs encouraging people to replace all lead piping. Another gray metal threaded pipe that many people mistake for lead piping is made of steel. The gray material is a galvanizing that they have added to the pipe to keep the water away so that the steel will not rust.

About fifty years ago, professional plumbers started using more copper pipe instead of threaded galvanized steel pipe for water pipes in the house. Copper is a more expensive material, but because it installs much faster, it ultimately winds up being a little bit cheaper because the homeowner is saving on labor costs in the installation.

In the 1980s, plumbers started to use more plastic pipes for water distribution, not just waste and vent piping. Some plumbers in the St. Paul and Minneapolis metro area had tried plastic water pipes.

They did not like it for its lack of durability. Shortly after, there was a plastic pipe developed in Europe called PEX. It is a cross-link polymer pipe, and over time, St Paul Pipeworks plumbers have discovered that it is in most ways better than copper. It is stronger than copper and installs faster.

Many other properties are better, so today, at least in this geography, if you look at a job installed by a plumber, almost all the time PEX will be used for water piping.

If you are interested in replacing some of the older piping in your home or are just looking for a quality plumber in the St. Paul and Minneapolis metro area, give St Paul Pipeworks a call today.

Yours Truly,

Matthew Dettwiler

Social Media Manager


Q: What are the different types of plumbing pipes commonly used in homes?

A: In basic plumbing, there are three primary types of plumbing pipes used in homes:

  • Water Pipes: These pipes are responsible for carrying fresh water into your home.
  • Waste Pipes: Waste pipes lead wastewater out of your house.
  • Vent Pipes: These pipes are connected to the waste system and provide air to help eliminate odors from the waste system.

Q: Can you explain the changes in plumbing pipe materials over the years?

A: Certainly! Plumbing pipes have evolved over time due to improved technology and manufacturing techniques. Traditionally, waste and vent pipes were made of cast iron or galvanized steel. However, modern options include plastic pipes, such as Polyvinyl Chloride (PVC) and Acrylonitrile Butadiene Styrene (ABS). These plastic pipes must meet specific ASTM standards to ensure safety and compliance with plumbing codes.

Q: Are plastic waste and vent pipes safe and up to code?

A: Yes, plastic waste and vent pipes, including PVC and ABS, are generally up to code in most plumbing regulations. They undergo rigorous testing and are assigned ASTM designation numbers to ensure their suitability for plumbing applications. Professional plumbers ensure that only approved plastic pipes and fittings are used.

Q: What are the key differences when installing plastic piping compared to metal piping?

A: When installing plastic piping, plumbers need to provide more support to prevent sagging under the weight of water. Additionally, plastic pipes should be installed in areas without exposure to ultraviolet lighting. Clear plastic tubing may also be used to convey condensate from furnaces or air conditioners.

Q: Why is lead piping a concern, and what has been done about it?

A: Lead piping poses potential health hazards, especially to infants, young children, and pregnant women. Most lead pipes in homes have been replaced over time, but there are still some in service. Water utilities encourage the replacement of lead piping. Galvanized steel piping, often mistaken for lead, has a gray material added to prevent rust. Copper and plastic pipes have become more popular alternatives due to their durability and ease of installation.

Know The Difference Between Your Pipes: Ask A Plumber…