Beginners Guide To Home Plumbing Pipes


Every building you go into, whether it be the post office, grocery store, movie theater, a friends house or your very own there’s going to be an existence of intricate plumbing systems.

With these intricate plumbing systems comes plumbing pipes. These are made of many different materials and serve many different functions for the overall use of the system.

So what kind of pipes should you expect to have in your home? There are pipes that deal with drainage of wastes from such fixtures as a toilet, shower and sink as well as pipes that convey water to the home and pipes that allow the plumbing system to breathe.

These pipes can come in a range of different materials, some have been outlawed over the years due to various different reasons, while others are perfectly fine but aren’t chosen in plumbing systems due to reasons like cost, weight and labor time.

If you want to find out more about the different plumbing pipes that can be found in houses all across America and Canada, then stick around.

This article will attempt to show you what the different styles of piping are used in your house, what their specific purpose is as well as teach you a bit about plumbing along the way.

Drainage & Vent Pipes

When I think of plumbing and pipes, I usually start thinking immediately about drains and vents. Drains are the the pipes that will take all of the things you don’t want in your house and send them on their maiden voyage to the pits of the sewer system, never to be seen again.

Drains and vents here in Canada are slightly different than ones found in America, but that’s only really based off of code. In Canada we primarily use a type of plastic pipe called ABS.

What is meant by drainage and venting? Drains are going to be piping attached to any fixture throughout your household that deals with waste of some sort. Some examples are the dishwasher, sink, toilet and shower. Vents are the piping that allow your plumbing system to breathe. These pipes will break airlock in the plumbing and allow waste to flow freely. I have a whole other article on plumbing vents, so if you would like to read more on why they are important you can click here to do so!

ABS (Acrylonitrile Butadiene Styrene)

ABS is a black pipe that is found in the homes of many across Canada. For residential use the sizes range anywhere from 1 1/4″ pipe size diameter all the way up to 4″.

The standard length of these pipes is 12 feet in length, and are a relatively cheap product to purchase. This type of pipe is used for drainage and venting in a home, and can also be used at times in commercial buildings.

The main draw for this type of pipe is it’s light weight and durability. The pipe can withstand any Canadian winter that’s thrown at it, as well as the overly muggy, hot and humid days we experience as well.

I personally am glad that my plumbing apprentice career primarily dealt with this style of pipe and my back is definitely thanking me for it (will get into heavier pipes later).

I often times was able to use a hacksaw to cut through this pipe, but preferred to use a sawzall for speed.

This pipe utilizes ABS glue to form the pipe to it’s fittings. The glue acts almost as a weld, and forms the fitting to the pipe.

From experience of removing a fitting off of a freshly glued pipe, you can really see how the pipe almost melts to the fitting, it looks like string cheese when you’re pulling it apart.

There is another style of pipe that’s even lighter than ABS that is becoming more and more popular in the plumbing industry and that’s Cellcore. This pipe is actually really lightweight and has a dull black surface as opposed to the shinier black surface a true ABS has.

The main drawback with the Cellcore pipe is that when it’s exposed to UV rays from the sun, it as we say in the trades: turns into a banana. The pipe will actually bend in the shape of a banana when left outdoors for too long.

This is actually true as well for ABS, although ABS doesn’t change quite as aggressively as the cell core does, and this is in part due to it’s rigid material.

The price of ABS is as follows:

Size (Inside Diameter)LengthCost (USD) (approximate)Weight (lbs) (approximate)
1 1/2″20 ft 22-257-9
2″20 ft25-3210-12
3″20 ft38-4220-22

*Cost of pipe will fluctuate over time with the market, so I felt it was best to show an approximate price based on what the pipe is priced at currently.

PVC (Poly-Vinyl Chloride)

This is going to be the main pipe found in the drain, waste and vent systems of the average American home, but you may also less commonly find ABS. The PVC is kind of like the yang to ABS’ yin, in the fact that it is purely a white pipe.

The main time I used this form of pipe was actually in commercial buildings, and primarily it was used for underground services. We used a purple PVC glue to attach the pipe to the fittings, and worked much like the ABS did.

PVC in American homes however comes in lengths of 10 feet with the standardized diameters that are much the same as the ones we have here as well as the use of primer prior to gluing is used as well in American homes.

The standard diameters are:

  • 1 1/4″
  • 1 1/2″
  • 2″
  • 3″
  • 4″

Primarily you are going to be using the 1 1/4″ pipes for places where the level of solids going down the drain is minimal eg. bathroom sink. The standard size of pipe used for the majority of the fixtures in your house is going to be in 1 1/2″. These include:

  • Kitchen sink
  • Bathroom sink
  • Shower or tub
  • Floor drain

1 1/2″ pipe is also heavily used for the venting of many fixtures in your house. Vent piping is the allowance for outside air into your plumbing system and is directly connected all the way up to and out the roof.

The next size up is 2″. This slightly larger pipe size and this is going to be used for anywhere that may have slightly more solid matter passing through it, or more space for air to pass. On a toilet drain where I live, a toilet requires a 2″ pipe to vent it.

A 2″ pipe can also be used on some shower and tub drains as well, and I personally liked to install these for people’s showers or tubs as it allowed for more room for hair among other things to pass through. The only time I wouldn’t use it is if space was more limited when working in a joist.

The bigger the pipe is always better. The reason you don’t always use the large pipes is, again because of space, and because it is less expensive.

When working with a plumbing system, you are never allowed to decrease a pipe size, only increase. So for example, if you have a 2″ vent pipe, that pipe must remain 2″ or greater the entire length of it’s run.

*Note – Your area’s code may differ from what I state here, this is a representation of what’s allowed and used where I currently live.

After 2″ comes the 3″ pipe. 3″ pipe is the standardized diameter used for all toilets. This pipe size is to ensure that the largest of the solids that will potentially get flushed down the drain, will be able to do get through without a hitch.

Also, 3″ (or 4″ pipe depending on where you live) is used to take the vent piping from inside the house, outside to open air. So no matter what size of vent pipe you end up with in the attic of your house, it will have to upgrade to the large size pipe to extend through the roof.

In Canada, our standard is 150 mm (5.9″) minimum, and in the United States as per inspectapedia:

“Vent pipes should extend to outdoors above the building roof and should terminate vertically not less than 6″ above the roof surface (nor more than 24″) and must be at least 12″ from any vertical surface (such as a nearby sidewall).”

Source: Inspectapedia
Size (Inside Diameter) Weight (lbs) (approximate) LengthCost (USD) (approximate)
1 1/2″5-710 ft7-10
2″7-910 ft11-14
3″14-1610 ft22-25

Cast Iron

The other style of drainage pipe that isn’t as popular as the two mentioned above due to weight and cost and that is Cast Iron. Cast Iron pipe is an alloy of iron and is found in a lot of older plumbing before the lighter plastics were invented.

This style is favorable for those who have a bit more money to spend on a project, and don’t like the sound coming from drains (the hard alloy acts really well as a noise insulator).

The main reasons this style isn’t being put as commonly into homes any more is because it is a lot more to work with. The overall cost of the cast iron pipe is as follows:

Size (Inside Diameter) Weight (lbs) (approximate)Cost (USD) (approximate)Length
1 1/2″28 – 3278-14010 ft
2″36 – 4079-14010 ft
3″52 – 56108-19210 ft

*Cost of pipe will fluctuate over time with the market, so I felt it was best to show an approximate price based on what the pipe is priced at currently.

Water Supply

The next main type of piping running through your home is the water supply pipes, and these range in material from the older galvanized steel pipe, to copper and all of it’s thickness’ to plastic pipes such as PEX and CPVC.

Galvanized Steel Pipe

If you live in an older home, one built before 1950, you may still have galvanized steel pipe running throughout your walls and joists to your faucets, toilets, showers and more.

This was the standard used for the time as it was a solid piece of pipe that when threaded (or screwed together) would create a nice water tight seal and would stand up to abuse thrown it’s way.

After 1950 however, they stopped using this pipe and switched over to copper pipe. The reason for this switch was because they found with copper you could still have potable (drinkable) water and rigid piping, but the pipes didn’t erode over time to cause clogging and low water pressure like the galvanized steel did.

There was also found to be trace amounts of lead inside of this style of pipe up to as much as 2%. Lead is absolutely unsafe for our consumption and may lead to illnesses and even death.

Because this pipe was dipped in zinc coating which helped elongate the lifespan of the pipes, they were also exposed to other impurities that may have been in the zinc molten mix, such as lead.

Now of days, this pipe more and more is getting replaced with the newer forms of pipes. If you still have this in your house, it may be best to consider getting it replaced.

Lead Pipe

Another form of water supply piping that was used was lead pipe. This was a popular pipe to use due to it’s malleability and strength, thus making it easy to install.

This form of pipe was used in homes up until the 1920’s until the toxicity of it had been discovered as a health risk to people. Even though the majority of buildings were being constructed with other forms of pipe, the use of lead was still found in solder.

It wasn’t until 1986 that they banned the use of lead altogether for potable water systems, and this included introducing a lead free solder.

This is a dull pipe, and when scratched the area becomes a silver grey. It’s very easy to bend, and recommended to replace it immediately, or not come in contact with it’s water supply at all.

Copper Pipe

After the galvanized pipe came the copper pipe, and is still used today in new construction. The different wall thicknesses are represented by letters. There’s type M, type L and type K, with type M being the thinnest, type K being the thickest but Type L being the most commonly used.

In a house you may find type M water lines run throughout the home, and in many places that is perfectly fine and up to code. Type M pipes traditionally will have red lettering on the side of the pipe to help you identify quickly the type of pipe.

There are area’s, such as commercial buildings however that deal with higher water pressures or untreated water, and that would require a thicker wall. So many places type M is not to code at all.

Type L is used in many different applications and doesn’t have as many restrictions as type M does. Many homes are being constructed today with the type L pipe. Type L is colored with blue lettering on the side of the pipe and type K has green lettering.

This form of pipe utilizes lead free solder for it’s assembly along with flux and comes in either 10 feet lengths or 20 feet.

To solder pipe, the end where the fitting goes on (such as a 90 degree elbow) gets sanded down with sand paper until it’s visibly shiny and clean looking. Next flux is added to the pipe, and all flux really is is a paste that allows flames from a torch to get attracted into the fitting.

Sand paper and flux are also required for the inside of the fitting as well. Because solder has a low melting point, a torch is all that’s needed to do the job. Once the fitting and pipe are heated up, a line of solder is placed where the end of the fitting and pipe meet, creating a water tight seal.

When hanging these pipes, it is best practice to use hangers that have a coating around the steel, or just copper supports. This is because of a scientific-y term called galvanic action.

When copper and steel are at a close proximity, an electrical charge can take place. When this charge happens it will weaken the strength of the copper, leaving it vulnerable for things like leaks and ruptures. Sometimes, duct tape is your best friend to protect the copper from metal.

Copper comes in two forms as well; soft drawn and hard. Soft drawn is really bendable and can be used for things like water supply to a refrigerator. Hard drawn is what will most commonly be found throughout a household due to it’s rigidity and is what water is used for potable water supply. You may also see soft drawn copper in your HVAC systems.

Over time, this type of pipe will experience another type of science-y thing called oxidation. Essentially the pipe will turn green in some parts due to extended exposure to moisture and air. Over time, many different chemical reactions will take place to form a layer of what’s known as “patina” which is the green substance on your pipe. This patina does not actually damage the copper.

Ninja tip: To differentiate between hot and cold water supply lines in your home without feeling the pipes, you can simply look at the darkness. The darker copper pipe is going to be your cold side, while the more regular looking copper is your hot.

Video on how to prevent copper pipe corrosion

PEX (Cross Linked Polyethylene)

The cheapest forn of water supply piping available to you is PEX. PEX has taken the plumbing world by storm for it’s ease of installation, durability and low cost point.

PEX started out in plumbing as the piping used for radiant in floor heating. This was because the material of pipe that was created for the purpose was flexible, could withstand the hotter temperatures, but wasn’t yet safe for human consumption.

PEX comes in coils that can range from 25 ft, 50 ft, 100 ft, 250 ft and above or even straight lengths of 10 ft (the straight lengths can provide a more aesthetic look in installation as they don’t come bent).

This type of pipe is usually white, but can come in either blue or red and will range in diameters from 1/2″, 3/4″, 1″, 2″, 3″ and 4″ with the 1/2″ and 3/4″ as the sizes found in most homes (the same can be said about other pipe materials as well).

Likely though, you’ll never see past 1″ water supply in a home at all unless it’s the main water line coming in from the street.

PEX uses rings to create water tight connections among pipe and fittings. You can do this by inserting the correct sized fitting into the pipe, placing a ring over top of the fitting and then using a PEX crimper to clamp down over top.

CPVC (Chlorinated Poly-Vinyl Chloride)

CPVC is another form of water piping that is commonly used in homes due to it’s light weight, ease of use and cheap material. This material can also be used for drains. I commonly see CPVC as drains for condensation pumps and hot water tanks.

CPVC utilizes glue to create a water tight seal between pipe and fittings. Just like PVC, first a primer is used, and then the glue is applied.

Where PVC is not a safe material for potable water supply, the extra layer of chlorine allows CPVC to be safe. CPVC can withstand hotter temperatures than PVC and won’t melt (so we won’t be getting bits of pipe coming out of our tap).

resources:

https://www.cdc.gov/nceh/publications/books/housing/cha09.htm

https://americanvintagehome.com/advice-for-older-homes/need-swap-galvanized-pipes/

https://www.bobvila.com/articles/pex-pipe/

Tyler Takacs

My name is Tyler, I live in Ontario Canada and enjoy learning about common plumbing issues in the household. I have spent just over three years in the trades as a plumbers apprentice, but am now onto a less physical job. I still enjoy studying and learning about my own house's plumbing as well as finding ways to help others with their issues.

Recent Content