How Do You Know What Size Shower Drain to Buy? [Solved]

Last updated on October 8, 2023

Want to replace an old shower drain? Here’s how to know what size shower drain you should buy. Read on!

In a nutshell, here are 2 ways how to be sure:

  • Take your old drain apart and measure the drainpipe’s diameter.
  • Buy an adjustable size shower drain.

There are other ways to find out your drain size and we set them out below.

Many people find it difficult to determine what drain size is necessary because a 2-inch or 1.5-inch pipe can be used for different applications.

If you are looking for an overview of the difference, you will want to know that a 2-inch pipe is usually found on showers, while the 1.5 inches are generally found in bathtubs and lavatory drain pipes that function as part of sink plumbing. The shower size is generally bigger than a 1.5-inch one has to do with the requirement for better drainage (more water is coming through.)

How to Choose the Size by the Type of Shower Drain?

shower drain size

There are three main types of shower drains by installation:

  • Tiled drains
  • Compression-style drains
  • Solvent-glued drains

Compression-style drains. If installing a shower base and drainage pipe, measure the height of the drain. Your measurement should be between ¾ to 1 inch from the edge of the hole in which you will be placing your shower drain. You may have to test-fit then remove your shower base for this step.

Solvent-glued drains. A shower drain typically comes in parts. Some resort to gluing them together. All stocked models come with predetermined measurements, but some tips can make it easier to decide on the right one.

Drain assemblies for custom-tiled showers are three-piece units, with each part installed at a different stage of the tile installation. Once the waterproof membrane liner for the shower is sandwiched between two lower flanges (sometimes there’s a third middle flange), these pieces are bolted together. They will form the lowest layer of water resistance in case any water gets underneath. The final piece is installed later on, which secures all parts and makes them visible during completed work. Your measurements have to match exactly.

What is the Size of Drain Pipe for a Shower?

During a bathroom remodel or home construction, installing a new shower is common. Many people are asking what size pipes should go into the drain of this shower they’re building. Before we get into the exact specifics of which pipes and structures will be added, it’s important to understand why these sizes need to be bigger than normal.

Most contractors try to get away with using a small pipe size of 1.5″ for their shower drainage, but it may not be sufficient to keep the shower from flooding and overflowing onto the bathroom floor. A couple of instances will spell major problems for your flooring and subflooring, so you want to do everything possible to prevent this.

Ensure you use a larger shower drain pipe size to keep the water from flooding the floor. 2 inches is common for shower drain pipes.

What is a standard-size pipe? Most shower pans will be fitted with a two-inch pipe. Standard building codes require this size of pipe for every shower. Various things make up the plumbing system, including pipes for water and sewage disposal. In the past, brass or lead pipes were common materials used to make drains and water mains. The typical size dimensions for these pipes today usually range between 1/2 inches in diameter or 3 inches in diameter.

If a two-inch drain pipe size code is desired for your shower or you’re unsure what to do, you should check the local building code for your state and city first. State and local codes may vary in drain pipe sizes, so it’s best to find out what works before installing. When installed properly, a shower pan size will accommodate either 1 ½ or 2-inch pipes. Two-inch pipes are often only needed when there is significant demand for plumbing.

Drain Pipe Size Discrepancies

You may run into the problem of having a 2-inch shower drain, but your drainpipe is 3 inches. Even though these cases are rare (check your local codes), it’s best to prepare for them. Adjustable size drains are available, and they can work on 2 or 3-inch drainpipes just as well.

How to Determine the Length of the Linear Shower Drain?

The size of the shower and the location of the drain will determine what length linear shower drains you should install. Together, these two factors must be considered so that the end is installed at a uniform distance from both walls and covers less than eight to ten centimeters on either side.

When installing it wall to wall, a linear shower drain needs to be the same length as the distance between walls, with at least 4 inches on all sides. The required length of a linear shower drain should not be longer than the distance between two adjacent walls.

You can find the specifications for linear shower drain installation at the website of the manufacturer. It would help if you read before you install to do it safely without damaging anything on your property.


Are all shower drain covers the same size?

Shower drain covers come in different sizes to fit different types of drains and their dimensions. Always check the specifications.

What is a standard shower drain size?

The standard shower drain size is 2 inches. But 3-inch drains are also common.

Is it OK to cover a shower drain?

It is OK to cover a drain with a designated drain cover (a.k.a. a hair catcher.) It serves the purpose to keep hair and other debris away from the parts of the drain. But it should never obstruct the water flow.


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