Parts of a Bathtub: 10 Key Components

Your bathtub is more than just a tub. While some tubs have fancy jets and additional features, even your most basic bathtub still has some serious plumbing work. Otherwise, we’d all be stuck bathing in barrels with buckets like they did in medieval times. Here are some key bathtub parts to know—whether you’re planning a bathtub replacement, want to fix some leaky parts, or just have an interest.

What to Know About Bathtub Parts

All bathtub components contribute to functionality and comfort. Most bathtubs are made of acrylic, fiberglass, or enamel-coated steel. Safety features are connected to control water flow and prevent overflow.

Bathtub 

The tub is the part we typically think of when it comes to bathtubs. It’s the basin that fills with water. Of course, there are a few different types of bathtubs to choose from. A clawfoot tub is a free-standing tub supported by legs, whereas an alcove tub—the most common type in the United States—connects to the wall.

Tubs come in all kinds of materials at different price points. The cost of a bathtub made from fiberglass could be as low as $200, while a ceramic tile bathtub could cost as much as $10,000.

Tub Abutment

If your tub connects to the wall, it will have a tub abutment. This bathtub part directly attaches your tub to the wall and holds it in place, but you might know it as the place where you line up your shampoo and bodywash bottles. It’s typically sealed with silicone caulk to make it waterproof.

Water Supply

The water supply is how you can control the water that enters your tub. There are a couple main parts:

• The spout, which directs water into the tub

• The faucet, which lets you adjust the temperature

Most faucets have a hot and cold tap connected to the correlating water supply pipes. It’s a similar configuration to your kitchen or bathroom sink. In some modern systems, you use a single lever to switch from hot to cold water from the supply lines. If you have one spout, a diverter pipe will help you get the perfect mix of hot and cold water—but that’s not always true.

In places like Europe, tubs with dual spouts are common. In this case, one spout pumps out hot water, and one pumps out cold water. Your tub may also have a hand shower (or handheld showerhead) that you can detach.

Water Supply Pipes

The water supply pipes draw water from your home’s main water line to your bathtub’s water supply, which lets you control the temperature and flow of water into your tub. Each tub has two supply pipes:

• A cold water supply pipe that provides cold water

• A hot water supply pipe that provides hot water

These supply lines are typically connected to a diverter pipe that lets both lines come out of a single spout. A cartridge valve connected to the hot water line allows you to control the temperature.

Shower

Not every bathtub has a shower, but it’s actually increasingly common for homeowners to hire a local bathtub replacement pro to rip out their tub and install a walk-in shower. Bath-shower combinations are popular for families with young children. Though there are different types of showers, they’re all made up of a few key parts of the tub:

• Showerhead: This is where the water comes out. It’s either attached to your wall or attached with a flexible hose or sliding bar.

• Shower control: Also known as a diverter valve or shower handle, this device typically rests between the showerhead and the water supply. It lets you switch the flow of water between the bathtub, shower, and (if you have one) hand shower.

• Diverter pipe: This pipe carries water diverted from your bathtub spout to the showerhead.

• Shower valve: The shower valve is located behind the shower control and controls the temperature and flow of water. Some valves are also pressure-balanced and can prevent dramatic temperature changes. The typical shower valve costs between $50 to $400.

Wastewater Drain

The wastewater drain is the drain at the bottom of your tub, typically located below the spout. There are three main parts in this section of the system:

• Stopper: We typically think of this as the drain itself. It plugs the drainpipe so you can fill or drain your tub. It also prevents items that could clog the pipe from falling down the drain.

• Waste outlet: This part of the drain system pulls wastewater into the sewer.

• Trap: A trap is typically connected to the waste outlet to prevent harmful (or smelly) sewer gasses and substances from entering your home’s water supply line.

Tub Overflow Drain

The tub overflow drain prevents flooding when you overfill your bathtub. It’s usually on the side of the bathtub below the spout.

• Faceplate: This is the face of the drain. Typically, it’s a metal cylinder. 

• Overflow pipe: This pipe connects to the faceplate and diverts excess water to the pipes behind the main drain, so it doesn't end up on your bathroom floor.

Planar Cross

This is a four-cross pipe connection installed in bathtubs. It connects your water supply, the diverter pipe for your shower, and the drain, allowing water to flow from your home’s plumbing system to the different parts of your bathtub. 

Shut-Off Valve

Some bathtubs have water shut-off valves on the water supply pipes. These should let you manually stop the flow of water into your bathtub plumbing if you need to make repairs. With some bathtubs, you’ll have to shut off the main water line to your home.

Access Panel

Some tubs have an access panel that easily lets you access the bathtub plumbing. Your local plumber will open this panel to make repairs, but not all bathtubs (especially alcove tubs) will have this panel.

How Much Does It Cost to Install a Bathtub?

If you're considering replacing your bathtub, it's essential to know that the cost can vary significantly based on several factors. Space constraints, reinforcement needs for flooring, and desired finishes mean bathtub installation costs can range from $1,910 to $9,160. Then, there's the cost of the tub to consider. Basic builder-grade models start at around $200, while a high-end clawfoot can cost you $14,000.

DIY vs. Hiring a Pro

Whether to install it yourself or hire a professional bathtub installer depends on your DIY expertise level and the project's complexity. If you have some plumbing and carpentry skills, simple installations like replacing an old tub with a similar one might be manageable and help you save on labor costs. 

However, hiring a licensed professional is best if the installation requires extensive plumbing modifications, structural adjustments, or specialized tools. Doing so will help ensure proper installation and avoid potentially costly mistakes or safety hazards.

Mariel Loveland contributed to this article.