Can you tell the difference in the plumbing pipes in your home? Let’s explore Water Pipes vs. Waste Pipes

When you are trying to identify whether a pipe inside your home is a water pipe or a waste pipe, the easiest way to do so is by size. The waste system pipes are generally larger in size. Even waste pipes coming from smaller fixtures are quite a bit bigger than water pipes. Most of the water pipes have an inside diameter of ½” to 1”. In a home it is rare for a water pipe to be larger than 1”. The waste pipes are usually at least 1 ½” to 2”, which allows waste to be conveyed away from the house.

In houses that have hot water heating, it gets a little more confusing because hot water heating pipes can be either of those sizes. Often when St Paul Pipeworks plumbers go into homes they find that people are confused about which pipe does what, because they have hot water heating pipes, water pipes and waste pipes for plumbing, and gas pipes, too. Sometimes the plumber will label the exposed pipes to help the customer know what each pipe does and in what direction each is conveying water or waste.

Many of the pipes that are part of the waste drainage system are vent pipes that are hidden inside of the walls. Vent pipes provide air to the waste piping system and without them, odors are not getting carried outside. They help equalize the pressure inside of the piping, assisting the draining function. Vent pipes vary in sizes between 1 ¼” to 4”. You need to have air provided to each plumbing fixture Code for the vent piping is more complicated than for the other piping systems.

Another thing that can be confusing about some of these pipes is now there are many different things that pipes can be made of. Before 1960, all of the water piping was usually threaded, galvanized steel. The old waste piping system was mostly black cast iron pipes with some galvanized steel. Around 1965, most of the pipes for water distribution were beginning to be made of copper. There was also a short period of time where some copper was used for waste and vent piping as well.

Today there is plastic pipe available for waste, vent, and water piping. Cross-linked polyethylene, (abbreviated to PEX) is used for most of the water distribution pipes. St Paul Pipeworks plumbers use the color-coding that is available in water distribution piping because it is easy for customers to recognize. Blue pipe indicates cold water, red pipe indicates hot water.

On the waste and vent side, there are plastic pipes that are white or black and are made of different plastic materials. The white pipes are Polyvinyl Chloride (PVC) and the black are Acrylonitrile-Butadiene-Styrene (ABS). St Paul Pipeworks plumbers generally use the black ABS pipes for waste and vent over the white PVC pipes because the properties of the ABS offer slightly better quality for the customer.

If you have questions about any of your plumbing pipes 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

Water Pipes vs. Waste Pipes: What’s the difference? Ask A Plumber