PVC pipes are the most commonly used pipes in residential plumbing systems. However, when you need to do plumbing or plumbing repairs, it may surprise you that a home’s plumbing system uses PVC pipes of various sizes.
This may leave many wondering what the most common size of PVC pipe is. Well, the answer is not a simple one because different pipes are used for different applications. Read on to find out more as we check out the most common sizes and give you all the information you need.
What are PVC pipes?
PVC (an acronym for polyvinyl chloride) is a plastic material used in plumbing. It is one of the five main types of sanitary pipesthe other types being ABS (acrylonitrile butadiene styrene), copper, galvanized steel and PEX (crosslinked polyethylene).
PVC pipes are lighter materials, making them easier to work with than other pipe options. PVC pipes are commonly used for sink, toilet and shower drain lines. They can handle high water pressure, making them suitable for indoor plumbing, water supply lines and high pressure pipes.
1. The advantages of PVC pipes
- SUSTAINABLE
- It can withstand high water pressure
- Resistant to rust and corrosion
- They have a smooth surface that makes water flow easily
- Easy to install (no welding required)
- Relatively cheap
2. Disadvantages of PVC pipes
- Not suitable for hot water
- Fears that PVC can introduce chemicals into drinking water
The most common PVC pipes around the house
Different sizes of PVC pipes are used in different areas of a residential health system. However, the most common around a house are 1.5″, 2″, 3″, and 4 inch pipes. So let’s take a closer look at where these pipes are used throughout the home.
1.5” pipes. – 1.5 inch PVC pipes are commonly used as drain pipes for kitchen sinks and bathroom sinks or bathtubs.
2″ pipes. – 2 inch PVC pipes are commonly used as drain pipes for washing machines and shower stalls. They are also used as vertical stacks for kitchen sinks.
3″ pipes. – 3 inch PVC pipe has many applications. Inside the house, they are commonly used for toilet pipes. Outside the home, 3-inch PVC pipe is commonly used for irrigation (carrying water to and from a garden hose).
4″ pipes. – 4-inch PVC pipes are commonly used as building drains under floors or in crawl spaces to carry wastewater from the home to sewer systems or private septic tanks. 4-inch pipes can also be used as drainage pipes in homes to collect waste water from two or more bathrooms.
As you can see, it is very difficult to answer the question about the most common size of PVC pipes, because all these sizes are used. If you need to replace the pipe and need to know the size, then it is best to measure it. Let’s see how you can do just that.
How to measure PVC pipe
Nominal scale measurement is used for PVC pipes, which means that the dimensions of these plastic pipes are based on their inside diameter (also known as bore).
So when you measure the size of a PVC pipe, you start by determining the outside diameter, but the end goal is to get to the inside diameter.
That being said, the steps to determine the size of a PVC pipe are as below.
- Hold the pipe stationary on a hard surface with one end up.
- Use a tape measure or ruler to measure the distance between the left and right outer edges of the pipe. This distance is the outside diameter (OD) of the pipe. Keep the ruler as level as possible when measuring.
- Match the measured OD with a PVC pipe size chart to determine the proper inside diameter.
You know that PVC pipes are labeled with the size and schedule. So when using a PVC size chart to determine the size of a pipe, you should use a chart that matches the pipe schedule.
A PVC schedule is the wall thickness of the PVC pipe. The different PVC schedules are 20, 40, 80 and 120, with the 40 and 80 schedules being the most common. The higher the PVC schedule, the thicker the pipe wall.
Thus, program 40 and program 80 will have PVC pipes with the same outside diameter different inner diameters. The wall of the thicker PVC Scaffolding 80 pipe is thicker from the outside to the inside, resulting in a smaller inside diameter.
The size chart for Schedule 40 PVC pipes is as follows:
PVC size (inner diameter) in inches | Outside diameter in inches | Pipe wall thickness in inches |
½» | 0.84 | 0.109 |
¾» | 1.05 | 0.113 |
1″ | 1,315 | 0.133 |
1 ¼» | 1.66 | 0.14 |
1 ½” | 1.9 | 0.145 |
2″ | 2.5 | 0.154 |
3″ | 3.5 | 0.216 |
3 ½” | 4 | 0.226 |
4″ | 4.5 | 0.237 |
5″ | 5,563 | 0.258 |
6” | 6,625 | 0.28 |
8” | 8,625 | 0.322 |
10″ | 10.75 | 0.365 |
The Schedule 80 PVC pipe size chart is as below.
PVC size (inner diameter) in inches | Outside diameter in inches | Pipe wall thickness in inches |
½” | 0.84 | 0.147 |
¾» | 1.05 | 0.154 |
1″ | 1,315 | 0.179 |
1 ¼» | 1.66 | 0.191 |
1 ½» | 1.9 | 0.2 |
2″ | 2.5 | 0.218 |
3″ | 3.5 | 0.3 |
3 ½» | 4 | 0.318 |
4″ | 4.5 | 0.337 |
5″ | 5,563 | 0.375 |
6” | 6,625 | 0.432 |
8” | 8,625 | 0.5 |
10″ | 10.75 | 0.594 |
Schedule 40 vs Schedule 80 PVC Pipe
Schedule 40 and 80 are the most common PVC pipes. Schedule 40 finds application in drainage and low pressure water flow systems, while the thicker program 80 pipes find application in pressure pumps that require stronger PVC pipes.
Schedule 40 and 80 PVC pipes have similar outside diameters so they can use the same fittings. However, because a Schema 80 pipe has thicker walls, its inside diameter is smaller than that of a similarly sized Sche 40 pipe.
Frequent questions
1. Is PVC pipe measured by ID or OD?
Using nominal scale measurement, PVC pipe sizes are named by their inside diameters (ID) and not their outside diameter (OD). That is, for a 2-inch PVC pipe, the hole is 2 inches wide.
The PVC pipe measurement «inside diameter» is known as the nominal size. The name «nominal» is appropriate because the measurement is in name only. If you measure the outside diameter of a PVC pipe, you will get a number larger than the given size (with the wall thickness of the pipe accounting for the larger reading).
2. What is the outside diameter of a 1.5” PVC pipe?
The outside diameter of a 1.5″ PVC pipe depends on pipeline schedule (or wall thickness). For example, due to wall thickness, a 1.5-inch schedule 40 PVC pipe used in drainage around the house has outside diameters of 1.9 inches.
From one edge to the other, a 1.5-inch PVC pipe measures 1.9 inches, not 1.5 inches.
3. How do I know what size PVC pipe I have?
There are two ways to know the size of PVC pipe. First, read the manufacturer’s markings on the side of the pipe. Second, measure the outside diameter (OD) of the pipe and match the reading to a PVC pipe sizing chart to determine the nominal size.
For the first method, look at the side of the pipe to find out his size. Most PVC pipes sold in hardware stores have markings on their sides indicating their dimensions. You will find them in decimals or fractions (such as 1.25” or 1 ¼”).
For unmarked PVC pipe, you need to measure the pipe to know what size you have. Use a ruler to measure the outside diameter (the distance from one edge of the pipe to the other), then look up a PVC size chart for the nominal size that corresponds to the OD.
4. What is the difference between PVC and CPVC and which is better?
PVC (polyvinyl chloride) is the plastic pipe widely used in plumbing systems. CPVC (chlorinated polyvinyl chloride) is a variant of PVC produced by chlorinating PVC.
CPVC pipes have a higher chlorine content, increasing their high temperature threshold. While PVC pipes can withstand temperatures above 140 F, CPVC can withstand temperatures down to 200 F, making them the preferred pipes for transporting hot water in HVAC (heating, ventilation and cooling) systems.
That being said, CPVC pipes are improved versions of PVC pipes.
Final thoughts
PVC pipes are the most common plastic pipes. Being durable and having a smooth inner surface that helps water flow easily, you often find PVC pipes in sewers, water mains and irrigation systems. The nominal system measures PVC pipes, with pipe sizes indicated by their internal diameters.
The most common sizes of PVC pipes are 1 ½ inches (used as drain pipes for kitchen sinks, bathroom sinks and bathtubs), 2 inches (used as drain pipes for washing machines and shower stalls), 3 inches (used in piped toilets) and 4 inches (used to connect homes to the sewer system).
It is vital that you select the right PVC pipe for your needs. We hope this guide will provide you with all the information you need if you are planning to repair or upgrade your plumbing system.