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What Is the Standard Shower Drain Size?

When you expect to renovate the bathroom or replace the faucet, basin, or shower drain, most people regard aesthetics or style first. However, it is often at a loss when actually proceeding. Are there any minor distinctions about the American standard of shower drain size compared with the one under building codes? Or what is the size of trap needed for a shower drain? With a series of technical and professional questions, you may be caught in the dilemma of where to start. Therefore, in this article, we will efficiently tackle three problems. What is the standard shower drain size? What are the differences between shower drain pipe size and bathtub drain size? How to install different types of shower drains? 

The Shower Drain Pipe Size
What is the proper shower drain pipe size?
The size of the shower drainpipe is often required for home renovations or construction sites.   Normally, the size of a typical shower drainpipe is 2 inches. And, in accordance with the requirements of the building code, the size of the drainpipe should be 2 inches. Less than 2 inches, such as 1.5-inch or lower, is likely to cause overflowing and flooding in the shower room. Furthermore, long-term wastewater blocking will lead to serious problems to the flooring and subflooring, mold or structural damage is common.

What is the standard shower drain pipe size?
The standard size of most shower drain pipes is 2 inches, carrying a larger amount of water so as to maintain smooth drainage. 2 inches is also the most common size required by building codes. Although some buildings have drainage tubes that are 1.5 inches or lower, larger pipes are more conducive to efficient indoor drainage. Therefore, 2 inches can be considered the most standard shower drain pipe size.

How about smaller size?
Compared with a standard 2-inch pipe, the 1.5-inch tube has a smaller opening, so the amount of water that can be carried per unit time is not as large as 2 inches. Of course, if your local building code requires your shower drain pipe size to be 2 inches, while you prefer a smaller size, you can try to glue a reducer to realize a slight opening. Before deciding to install a smaller drain tube, consider the water usage in the shower room. A 1.5-inch drain pipe size may not be able to achieve rapid drainage, so we recommend using a 2-inch shower drain pipe.

Shower drain pipe vs. Bathtub drain pipe
The bathtub drain pipe has the same function as the shower drainpipe, both of which are intermediaries for draining wastewater in the plumbing system. The shower drain is usually independent, yet the bathtub is not. If you are planning to install a bathtub in the bathroom, it is best to contact a professional plumber for measurement, installation, and testing.

Size discrepancy between shower drain pipe and bathtub drain pipe

The connection size of the shower drain pipe and the bathtub drain pipe is different. The size of the shower drainpipe is 2 inches, while the drainpipe of the bathtub is usually 1.5 inches. Therefore, the size of the shower pipe is slightly larger than that of the bathtub drain pipe. The multi-angle spray of the shower nozzle will accumulate a large amount of water in a short time, thus a larger diameter pipe port is required in the shower space to ensure rapid drainage. The 1.5-inch drain pipe in the shower room is likely to cause overflowing or flooding on the ground. The appropriate diameter is significant for the drainage of the plumbing system, thereby different showering systems should choose the optimal drainage pipe size.

Connection discrepancy between shower drain pipe and bathtub drain pipe
The wastewater in the shower room is directly discharged into the plumbing system through the trap inside the shower drain, but an outlet is needed between the bathtub and the plumbing system. The bathtub, like a giant sink, compulsorily requires a drain connection like a siphon to discharge wastewater.

Install different types of shower drain
Tools & Materials Needed
Shower drain assembly, pencils, drillers, silicon sealant, screwdrivers, and protective goggles...
Type of drain assembly
Compression-style drains
Solvent-glued drains 
Tiled drains
Different instructions to install shower drains

How to install compression-style drains

01. Cut the drainpipe
With the support of a professional plumber, the drainpipe should be installed below three-quarters to one inch of pipe. If the size is not suitable, it is recommended to mark the height of the measured drain base with a pencil, and then cut the appropriate pipe.
02. Attach the shower drain assembly
After the flange of the drainpipe is coated with the silicone sealant, insert the shower drain assembly into the opening in sequence.
03. Place the shower base
Put the shower base in the right position, making sure it connects well with the drain assembly.
04. Insert the compression gasket
Put the compression gasket into the opening and tighten the nut with a screwdriver to form a water-sealed airtight environment.

How to install solvent-glued drains
01. Trim the drainpipe
With the support of a professional plumber, trim off the drainpipe height. It is recommended to mark the height of the measured drain base with a pencil and then cut the appropriate pipe.
02. Prepare the shower drain assembly
Confirm all the parts of the drain assembly, such as the strainer, and put the cardboard friction washer and the rubber sealing washer in one place.
03. Fix the shower drain assembly
After applying a layer of silica gel on the flange, install the shower drain assembly in sequence, from the rubber sealing gasket to the paper friction gasket. Wipe off the excess silicone after tightening the parts.
04. Glue the drain assembly
Apply a layer of solvent glue on the surface, and then fix the drainpipe immediately. Wait for at least 24 hours before taking a daily shower.

How to install tiled drains
01. Install the bottom flange
Properly clean the periphery of the shower drain, and then install the bottom flange into the drainpipe with solvent glue. It is recommended to install a waterproof membrane liner on the lower of the bottom flange before proceeding to the next step.
02. Install the middle flange
Fix the middle flange on the bottom flange with bolts, and then use water after this step to check the liner for leaks.
03. Place the strainer assembly
Connect the strainer to the drainpipe and match it to the middle flange to reach a certain height to fit the surrounding tiles.

What is the American standard shower drain size?
A standard shower drain size is 2 inches in diameter, but a standard modern bathtub drain is 1 1/2 inches in diameter and 3-inch drains are also relatively frequent.
Is the hair catcher essential for a shower drain?
The hair catcher, a.k.a strainer, is useful to prevent hair and soap stains from clogging the plumbing system.
Are the covers of all linear shower drains the same length?
No, cover length can be selected according to different displacement requirements. It is crucial to make sure specifications and get what size you want.