6 Types Of Toilet Flanges (With Photos)

Types of Toilet Flanges

If you’ve ever had a loose toilet that wiggles and/or leaks where it meets the drain, you likely have an issue with your toilet flange. These problems are common, as the flange is responsible for connecting your toilet to the floor and to the drainpipe beneath. Unfortunately, there isn’t an exactly a quick fix in this situation. In most cases, the toilet flange will need to replaced.

Toilet flanges come in six main variations and three standard sizes, with the choice of an odd fit. The types of toilet flanges are categorized based on the material that they are made out of, including copper, brass, plastic (PVC), stainless steel, cast iron, and aluminum. Meanwhile, toilet flange sizes depend on the shape and diameter.  

It’s beneficial to understand the different sizes and types of toilet flanges in order to ensure that you purchase the right replacement flange for your particular toilet. After all, choosing the correct toilet flange could mean the difference between a hassle-free toilet and one that requires intervention for a second time. Let’s dive in.

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What is a Toilet Flange?

Also referred to as a closet flange (taking after “water closet, the traditional name for a toilet), a toilet flange is a pipe fitting or mounting base that securely joins the toilet to the floor below, while also joining the drainpipe to the home’s main drain sewer line.

The word flange comes from the French word “flanchir,” which means to bend. Flanges have been used for years to connect pipes and cylinder-shaped fixtures. Although flanges are mostly used for plumbing applications, they also are seen in camera lenses and train wheels. These often-misunderstood components are incredibly helpful and essential to securing an object by connecting it to another unit.

The flat surface of a toilet flange will feature a wax ring and a section where the screws or bolts are tightly fitted. The toilet itself is mounted atop the flange, instead of directly to the bathroom floor. While you ultimately screw the toilet into the floor, using a toilet flange is a safer and more efficient way to prevent leaks.

What Is Its Purpose?

Based on the above definition, toilet flanges serve two main purposes:

  • To securely fasten the toilet to the floor.
  • To hook the toilet up to the drainpipe/sewer below.

Another reason that a toilet flange is so important is that it prevents leaks via the wax ring, which seals any gaps between the flange and the base of the toilet. Using a toilet flange will also prevent any damage from occurring to the floor during installation, as you won’t have to drill directly into the flooring.

Without a toilet flange installed, your toilet cannot securely attach to the drain pipe. In theory, the toilet could connect directly to the floor or subfloor, but this installation will only last so long before you have leaks and rotting would that has to be replaced.

Types of Toilet Flanges

There are six main types of toilet flanges to choose from, categorized based on the material that they are made out of:

1. Copper Toilet Flanges

Copper is notorious for being incredibly resistant to corrosion, which makes copper toilet flanges a very durable option. Depending on your preferences, this type of toilet flange can be soft and flexible or rigid in nature. Soft copper flanges bend easily and tend to be simpler to install than their rigid counterparts. Hard copper flanges require elbow joints for them to effectively connect to the drain pipe. These elbow joints help to match the space and achieve a perfect fit.

As copper is biostatic, meaning it’s anti-bacterial and anti-fungal, it is a popular choice for toilet flanges. Its composition makes it an unsuitable host for viruses, fungi, or bacteria. For this reason, copper toilet flanges are a safer choice for plumbing applications, as it transports potable water components better than raw metal.

2. Brass Toilet Flanges


Photo via Amazon

Brass is an alloy of both copper and zinc, meaning it is very strong. The material is also malleable, resistant to rust, and highly resistant to corrosion. Brass toilet flanges are available in two forms: simple circular flanges and those that require elbow joints to allow for effective connection to the drain pipe.

These toilet flanges also come in a variety of sizes and shapes, including regular, deep seal, and offset sizing. This material can also withstand high heat, which contributes to its durability. The drawback to brass toilet flanges is that the material is incredibly heavy and is prone to oxidization when exposed to air.

3. Plastic (PVC) Toilet Flanges

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Polyvinyl chloride (PVC) toilet flanges are the most popular type available. They can be used for both residential and commercial applications, and are the most affordable option on this list. The major advance to using PVC toilet flanges is that they very strong, rust-resistant, durable, and lightweight.

One alternative to PVC is known as ABS plastic, which is just as lightweight, but even more durable. Although ABS plastic usually costs more than PVC, it can withstand more robust waste and running water.

Some plastic flanges are made of 100% plastic, while others feature metallic tops to make the wax ring. Though, all PVC toilet flanges are designed to fit three- or four-inch drain pipes. Although plastic a great choice, they are more prone to buckle under high pressure – even in the case of ABS plastic that is more resistant to shock, water and heat.

4. Stainless Steel Toilet Flanges

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Next on our list is the stainless steel toilet flange, which also boasts rust and corrosion resistance. This type of flange is more durable and offers a better seal than alternatives. It also is lighter than other metal types. When it comes to stainless steel flanges, the stainless steel usually only refers to the wax ring material. Meanwhile, the rest of the flange can be made of plastic, copper, or cast iron.

As there are numerous types of stainless steel out there, the most common one is 304 that consists of roughly 8% nickel and 18% chromium. More advanced options feature added silicon to reduce the risk of oxidization.

5. Cast Iron Toilet Flanges

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Cast iron toilet flanges are specifically manufactured to only pair with cast iron pipes. They are incredibly strong, durable, and available in numerous sizes. Though these flanges have a different shape, with an elongated pipe that is designed to fit deeper into the drain pipe. This is known as a deep-body cast iron flange.

This type of toilet flange is best suited for drain pipes that are located beneath the subfloor. Like stainless steel, cast iron also comes in many forms. The drawback to cast iron toilet flanges is that the material tends to rust faster than other types of metals.

6. Aluminum Toilet Flanges

Last, but certainly not least, is aluminum toilet flanges. This material is lightweight, resistant to corrosion, and durable. While it is most often used to make the wax metal ring, aluminum may also be used in the construction of the entire toilet flange. Aluminum comes in many types, with the best being unadulterated aluminum. Though, an alloy with manganese, zinc, copper, or magnesium can add more durable to the flange.

Toilet Flange Sizes

In addition to material, toilet flanges can also be categorized based on size. The size depends on their shape and diameter. Let’s take a look.

Toilet Flange Shapes

The three primary shapes that are used in the design of a toilet flange are as follows:

  • Regular: These flanges are designed to fit around and inside the opening of a drain pipe. They have the smallest depth, only going into the pipe approximately five inches, or so.
  • Deep Seal: As the name suggests, deep seal flanges extend into the pipe deeper than their regular counterparts – roughly 12 inches deeper.
  • Offset: These shaped flanges are ideal for oddly positioned openings like when the pipe opening is too close to the wall or far from the floor. They include an elbow for easy installation and adjustment of the flange, which is located inches away.

Toilet Flange Diameters

Toilet flanges can be installed into or over the drain pipe. For this reason, there are only two toilet flange diameters to choose from: four- and three-inch.

Standard 4×3 Flanges

Standard 4×3 toilet flanges are a common size that fits most toilets and are widely available in most plumbing, hardware, or home improvement stores. The 4×3 describes two diameters, the component that connects to the toilet (four inches) and the bottom diameter that fits to the drain pipe (three inches). The difference is where the three-inch base diameter is designed to pair with a 40 pipe, used in most homes as the standard size for drain pipes.

3-inch Flanges

These types of flanges simply indicate that the diameter of the top and bottom area is both three inches. Although these are the easiest option to install, you want to ensure that your piping is sized correctly. If you don’t have a three-inch pipe, consider opting for a different toilet flange is a three-inch flange may offset the alignment of the plumbing.

You can also find four-inch flanges that have four-inch diameters on the top and bottom. Though, these are much rarer compared to the three-inch toilet flanges.

Odd Sized Flanges

Aside from the two main flange diameters, there are oddly sized flanges that measure smaller or bigger than the standard 4×3 toilet flange. A common example is an ABS plastic flange that has a seven-inch top diameter and a 3 1/2-inch base diameter. These flanges will require extension kits to raise the height of the flange enough to fit the requirements of the installation.

Other oddly sized flanges feature a diagonal set offering extra space, particularly for elongated toilets that replace a round toilet. This requires an extension.

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How to Know When Your Toilet Flange Needs to Be Replaced

It can be hard to tell if your toilet flange is broken, as it is out of view underneath the toilet. However, there are some signs and symptoms that may indicate a problem with your flange. Here are the symptoms that you should keep an eye out for:

  1. Leaking from the bottom of your toilet. If your toilet starts to leak from the base, this is likely caused by an issue with the flange. It may be either a crack in the flange or the flange may be the wrong size for your toilet.
  2. Your toilet moves back and forth. If your toilet wiggles or rocks back and forth, this is a strong indication of a problem with the flange.
  3. Your bathroom has a sewer smell. Rotten or sulfuric odors in your bathroom without a leak may mean that the flange is broken just enough to allow the smell to enter your bathroom.

Familiarizing yourself with these common symptoms can help you stay on top of problems and replace your toilet flange accordingly.

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Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

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