SDR 35 vs Schedule 40: Which One Should You Use?

Making the drainage and sewage system of bathrooms is always hectic work. It’s a tough job to choose the correct equipment. Choosing between SDR 35 & Schedule 40 pipes makes the task harder.

Which one is the winner in the SDR 35 vs Schedule 40 battle?

Both SDR 35 and Schedule 40 have perks and drops. SDR 35 is cheaper and flexible. Gives good performance when used underground. On the other hand, Schedule 40 is a strong pipe. It has good pressure endurance. The price is more for this pipe. But Sch 40 will give a long-term service if used indoors.

Before taking the decision check every criterion properly. Select the best pipe according to the sewage system. 

Scroll down for more details-

SDR 35 vs Schedule 40: Short Comparison 

Choosing between SDR 35 and Schedule 40 is as difficult as choosing between 10 2 or 10 3 wires for the air conditioner. Before deciding on the pipe you want to use it is better to know all the details. But if you’re in a rush, you’ll be looking for a short suggestion. We’ve prepared a comparison box for your convenience.

Check out the comparison box and know every point you need to know at a glance!

FeaturesSDR 35Schedule 40
StrongnessLess StrongMore Strong
Flexibility HighLow
Joint TypeRubber Gasket/GlueGlue
Preferable Use Exterior PipelinesInterior Pipelines


These are the main comparisons between the SDR 35 and SCH 40 pipes. But if you’re still confused and want to know more, keep scrolling. We have discussed both pipes in detail below for a better understanding. 

SDR 35 Vs Schedule 40: Detailed Discussion

All the crucial points of difference between these two pipes are given in the above table. But there are always more details. Often not knowing the details will create problems like Larson Storm door installation problems. For that reason, we have made a detailed list of the advantages and disadvantages of SDR 35 and Schedule 40. Keep reading to learn about all these details.

SDR 35 

SDR stands for Standard Dimension Ratio. This is a method of pressure rating piping. The SDR number is the ratio of the pipe diameter to the wall thickness. 

So if you use an SDR 35 pipe, it means the outside diameter of the pipe is 35 times more than the wall thickness.  The SDR number has significance. A pipe with high SDR means it has thin walls compared to the pipe diameter. Conversely, a pipe with low SDR has a thick wall compared to the diameter. 

Moreover, a high SDR pipe will have a low-pressure rating. This means it will be able to bear less pressure before collapsing. In the same way, a low SDR pipe has a high-pressure rating. 

Advantages of SDR 35 Pipes 

The SDR 35 pipes can be used for drainage and sewage systems. These pipes are not as thick as the SCH 40 pipes. But SDR 35 pipes are very flexible. As the pipes are not very thick they have flexibility. 

SDR 35 pipes are good for outside use. You will get great benefits if you employ the SDR 35 pipes underground. The soil composition always tends to change. They are always shifting and changing. If you use a pipe with flexibility it will easily cope up with the changes. In these situations, SDR pipes are of great use.

The joint system of the SDR 35 pipes consists of gaskets. Gaskets are easy to fit. They perform better when used underground. The pressure of the soil keeps the gasket in place.

The price of SDR pipes is also less than SCH 40 pipes. The installation process is quite easy too for these pipes.

Disadvantages of SDR 35 Pipes

The SDR 35 is less strong. They are not very thick. For these reasons, SDR pipes are not suggested to use in the interior. The pipe has gasket joints that can cause problems when used vertically. The SDR 35 pipe is not capable of handling high pressures.

Schedule 40 

The Schedule 40 pipes are also known as SCH 40. The term Schedule is used to clarify the thickness of the pipe. The SCH number is the ratio of the internal working pressure of the pipe and the stress the pipe material can endure. There are different types of stresses in a pipe.

This number is non-dimensional. The pipe schedule depends on the internal pipe pressure, the materials used to make the pipe, and the nominal size of the pipe.

The relation between pipe diameter, wall thickness, and schedule number can be found in the schedule table. There are pipes of many schedule numbers. But SCH 40 and SCH 80 are most commonly used.

Advantages of SCH 40 Pipes 

As the schedule says, SCH 40 pipes are thick. These pipes are very strong. The pressure enduring power of SCH 40 pipes is very high.

For these characteristics, these pipes are used in the interior sewage and drainage systems. The thick pipes you see outside houses are generally SCH 40 pipes. When used in the interior system they give great service. 

The pipe can withhold 600 psi of pressure which is more than the SDR 35 pipe. Though the pressure sustaining capacity of SCH 80 is more, SCH 40 also gives good support.

The pipe connections are given by glue. It might sound complex but it is good for use in the interior. 

Disadvantages of SCH 40 Pipes

The SCH 40 pipes are strong because they are thick. And for the same reason, they are not flexible. The flexibility of pipes is necessary for some aspects.

When used underground the SCH 40 pipe can face problems. The soil and nature always change by shifting. In this type of situation, the SCH 40 pipe can rupture. This pipe is so rigid that it can break even if the ground settles or shifts.

The schedule 40 pipe becomes more brittle in the winter. The cold and low moisture affects the pipe and makes it brittle. So when used underground the structural integrity could be compromised.

This pipe connection is made with glue. You can use the following glues we have suggested with the SCH 40 pipe.

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These glue products will be very good to use with the pipes. We hope you will be happy after using our recommended products.

The price of the SCH 40 pipe is more compared to the SDR 40 pipe. But the price is high only because the SCH 40 pipe material is thick.

SDR 35 vs Schedule 40: Final Verdict 

Giving a final verdict is not an easy task. It’s as difficult as selecting between rubber vs foam pipe for insulation. We have tried our best to give you the rightest verdict.

From our article, you can see that both pipes have their advantages as well as disadvantages. It’s not an easy choice to choose between them. But we can give you a verdict based on our perspectives. 

The SDR 35 pipes are recommended if you are looking for flexibility. For underground drainage say, stem this pipe will be very useful. The SDR 35 will be able to withstand ground shifting. So you’ll get a long-lasting service. 

We can’t ignore the SCH 40 pipes. These pipes are recommended for their strongness and thickness. When used indoors the SCH 40ely the winner. Though the price is more, you will get a quality service from SCH 40 pipes.


How much weight can  PVC pipes take?

The answer depends on the type of pipe you are using. SCH 40 pipes with a 1.5-inch diameter can take 954 pounds. Whereas an SCH 80 with a 1.5-inch diameter can take 1225 pounds.

What is the diameter range of SDR pipes?

The SDR pipes can range from a 4inch diameter to 3 feet diameter. Nevertheless, most residential usage of SDR pipes is covered by 6-inch diameter pipes. 

Is Schedule 40 used for drainage sewage pipes?

Schedule 40 is a very popular pipe all over the world. But it is mainly used for indoor works. However, in some outdoor works, SCH 40 is used for its smooth wall. Many customers also choose this pipe for its looks if the system is exposed.


We’ve provided you with the very information you need. Now you can select the winner in the SDR 35 vs schedule 40 pipes battle. Make your decision wisely.  If you have any queries easily on this topic comment below.