Components of a Typical Bathtub
Whether soaking in a relaxing bubble bath or quickly rinsing off after a long day, most of us use our bathtubs frequently without giving much thought to how they actually work. Bathtubs may seem simple, but they contain many parts that work together to deliver an effective bathing experience.
When we step into a bathtub and turn on the faucet, water comes pouring out, fills up the tub, and then drains away when we're done. But what's happening behind the scenes to make this possible? Let's explore the key components that make up a typical bathtub.
Bathtub Shell
The outer shell or casing of the bathtub is the main visible part and holds the water. Tub shells come in several materials, shapes, and sizes.
Materials
The most common materials for bathtub shells are:
- Acrylic - plastic composites that are lightweight, scratch-resistant, and inexpensive.
- Fiberglass - a composite of fiberglass cloth and plastic resin that is durable but can scratch over time.
- Porcelain enamel steel - a steel tub with a glossy, porcelain enamel coating that is very durable but heavy.
- Cast iron - a very durable but extremely heavy old-fashioned tub material.
Acrylic and fiberglass are the most popular choices today for their affordability, lightweight yet durable construction.
Shapes
Some typical bathtub shapes include:
- Rectangular - a classic straight-sided tub that fits against three walls.
- Corner tub - fits into a corner of the bathroom.
- Oval - an elliptical-shaped tub with rounded edges.
- Freestanding - a standalone tub not connected to walls.
Rectangular and oval tubs are most common, but corner tubs save space and freestanding tubs create a spa-like statement.
Sizes
Standard bathtubs are usually 60" long, but sizes can range from small 48" alcove tubs to large 72" models. Extra deep or wide air jet bathtubs are also available for a more immersive soaking experience.
Drain Assembly
One of the most important parts of a bathtub is the drain assembly which allows water to exit the tub. Key components include:
Drain
The drain opening at the bottom of the tub where water flows out.
Drain Pop-Up Plug
A movable stopper that seals the drain closed until the user is ready to let the water out.
Overflow
An opening a few inches higher than the main drain that acts as a overflow relief to prevent tub overfilling.
Trip Lever
A lever on the tub's side that lifts the pop-up plug to open the drain and let water out.
P-Trap
A curved section of drain pipe designed to hold water and prevent sewer gas from entering through the drain.
Proper installation of drain components and watertight seals are needed to prevent leaks.
Piping
supply pipes and drain pipes are required to convey water into and out of the bathtub.
Supply Pipes
Hot and cold water supply pipes, usually copper or PEX tubing, deliver water to the tub's faucet. Shutoff valves on the supply pipes can turn off water to the tub.
Drain Pipes
Larger diameter PVC pipes are used to drain wastewater from the tub and connect to the home's main drainage system.
Traps
P-traps or S-traps hold water to prevent sewer gases from entering through drain pipes. Regular cleaning is needed to prevent buildup.
Fixtures and Features
Various plumbing fixtures and accessories are installed with most bathtubs:
Faucets
Faucets control the flow and mixing of hot and cold water into the tub. Single-handle or dual-handle designs are common.
Showerheads
Most tubs have integrated shower systems with overhead rain showerheads or handheld showerheads.
Diverter Valves
Diverter valves route water flow between the tub's faucet and the connected showerhead.
Soap Dish
Built-in or removable soap dishes provide convenient storage for bathing essentials.
Grab Bars
Safety grab bars provide stability and prevent slips and falls in the tub.
Jets
Hydromassage jets blast streams of water for a spa-like soaking experience.
Lights
Soothing LED lights create a relaxing ambiance while bathing.
The right combination of fixtures and accessories can enhance your ideal bathing experience.
Advanced Features
Today's bathtubs offer advanced features like:
Digital Controls
Electronic controls allow users to digitally set their perfect tub filling temperature.
Bathing Modes
Preset bathing experiences like whirlpool massage, variable jet pressure, and sequenced lighting effects.
Bluetooth Connectivity
Wirelessly play music through built-in tub speakers for an immersive audio bathing experience.
Sanitization Systems
UV light or ozone sanitization can eliminate germs and bacteria from tub water and surfaces.
Smart Home Integration
Voice activation, mobile app control, and smart home connectivity for total tub automation.
With advanced electronics and programming, today's bathtubs provide luxury features to enhance relaxation and convenience.
Bathtub Plumbing System
For a bathtub to function properly, all of its components must connect together into a comprehensive plumbing system.
Water Supply
Hot and cold water supply lines use 1/2" or 3/4" copper pipes or PEX tubing to deliver water to the tub's faucet valve. Supply lines connect to the home's main water supply lines and are controlled by shutoff valves.
Drain/Waste System
The tub's drain outlet ties into a larger-diameter PVC waste pipe, around 1.5" to 3" in diameter. This waste pipe has a downward slope to allow water to drain by gravity into the main sewer line.
Vent System
Small vent pipes connect to drain pipes to equalize air pressure and siphon water out of the tub. Vents prevent gurgling drains and allow waste water to flow freely.
Understanding how these systems connect is useful when installing a new tub or troubleshooting issues.
Bathtub Valves
Valves control the flow of water into, within, and out of the bathtub:
Shutoff Valves
Let users manually turn on or shut off hot and cold water supply lines leading to the tub.
Mix hot and cold water to the desired temperature and control flow volume out of the tub's faucet.