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Bathtub Parts Everyone Should Know

While bathtubs may appear simple, there are many moving parts to consider when making a tub. Each part plays an important role in how your bathtub functions and more importantly, it is crucial to know what to look for in the event that something goes wrong. Here are all the parts of a bathtub:

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Water Supply

First and foremost is the water supply. The water supply provides water to your faucets and shower head peripherals, filling your bathtub with water. It is important to check your water supply periodically for any damages or pollutants, although typically, turning on your water can give you a clear indicator of its overall purity. Cold water is provided typically through your utilities either through a condenser or a tower, whereas warm water is usually distributed from your water heater.

Also, lack of cold water from your shower is related to your water cartridge in your shower, and similarly, lack of hot water is caused by issues with your water heater. If you live in an apartment complex, this will usually be controlled for each individual unit in your building. On the other hand, if you live in a home, the water supply will be buried underground or placed in your basement or crawlspace as to not disrupt you in any way.


Directly connected to your water supply is your shower, which provides an aerial stream of water for bathing. Most homes have a shower mounted on a higher angle combined with a bathtub below that serves as the drain. You can change the size of your shower heads, replacing them with more water efficient ones, but the tradeoff would be less water flow overall. Conversely, you can also change them to provide better water flow, but this will increase your water bill significantly. Your shower is controlled by a set of control valves that determine both hot and cold water independently. In older models, you should take care not to burn yourself as there is no temperature control for the water, whereas newer models have thermostat mixing valves that ensure no such incidents like scalding can occur.

When going through parts of a shower, it’s a good idea to inform yourself of their prices as well:

Shower partPrice
Shower control$100-$300
Diverter pipe$30-$200
Shower valve$50-$400


Similar to your shower, the bathtub provides a vessel for holding water for the purposes of bathing. While the shower is more for upright bathing, the bathtub is designed for bathing from a seated position. Typically rectangular or oval in design, all bathtubs have a central drain located at the base of the tub, which can be plugged for regulating water flow. As most bathtubs are shower combinations, water is controlled by similar valves-one for cold water, the other for hot with newer models containing thermostat mixing valves to ensure more safety concerning higher temperatures.

Tub price range: $400 – $2,000+

Shutoff Valves

Allowing control of the water supply to your home, there are two primary types of shutoff valves-fixture valves and primary valves. In newer homes or those built within the past 40 years, fixtures will have a separate stop valve running from the supply tube to your fixture. If it does not, then water will need to be cut off to your entire home, which would be the main shut-off valve. The main shut-off valve controls water flow to your entire house. If you do not have separate stop-valves, consider installing them for the purposes of an emergency.

Shutoff valves price range: $50 – $100+

Diverter Pipe

A diverter pipe is a piece of plumbing equipment used to divert or centralize the flow of water to a single area, or in other words, if you want hot and cold water to flow out from one faucet. They are commonly used in nearly all appliances such as bathtubs, freestanding sinks, and showers so that both flows of water can be joined together into a singular opening. The easiest way to notice whether you need to replace a diverter pipe is general low water pressure.

Diverter pipe price range: $30 – $100+

Planar Cross

Usually only installed in a bathtub, a planar cross is a four cross connection of pipes that control water flow. In this case, the planar cross connects to the diverter pipe as well as your cold, hot water supply and the rim of your drain, allowing for water to flow directly out from your bathroom. The reason it isn’t prevalent in other parts of your home is that with cross section arrangements, you risk having municipal water mixing in with your own.


The rim is defined by the upper edge of your tub or the lip of it. The lip is meant to both provide a secure base for your bathtub to rest on as well a way to catch water that may spill out from the top of your bathtub if full. Often times, however, the rim will get wet and the sealant underneath will start to wear thin, so it is best to caulk the area every once in a while.

Rim price range: $1,000+


The drain allows water to leave your bathtub or sink, specifically through the drain pipe. It is identified by a circular hole at the base of your bathtub or the bottom of your sink. If water does not flow directly out, it means that your drain is clogged, (a common problem) and you need to check the drain pipe for the direct problem. Often times, it is usually the byproduct of hair build up, which will clog the pipe and restrict water flow-installing a strainer to catch hair will save future headaches down the road.

The right drain depends on the type of bathtub you have. These are the factors you will need to keep in mind when choosing the drain for your bathtub:  

  • The pipe assembly material 
  • The actuator type 
  • The drain location measurements 
  • The drain stopper type 

Flexible Connector

A flexible connector is a pipe that shores up any connector problems that may exist in your plumbing. If, for instance, your pipes don’t fully connect to each other, a connector pipe, usually made from braided steel, is used for connecting your appliances to the water supply. They come in a large variety of sizes and bolt styles, allowing for easy adjustment into about just any home. Most common with newly installed sinks or a freestanding bathtub, flex connectors can help align your plumbing with that of your appliances.

Flexible connector price range: $30 – $60

Overflow Pipe

Located between your connections and the drain, the overflow pipe serves to catch all the excess water build up and direct it to your drain through a separate pipe. The general idea behind an overflow pipe is to lessen the load or general water flow to your drain, otherwise, it may stress the piping if a separate channel isn’t created for excess water to move through.

Overflow pipe price range: $30 – $100


A trap, or otherwise referred to as an ‘S-Bend’ is a specific type of piping that is designed in the shape of a sideways S. This design allows for the water to be trapped so that harmful substances and gases cannot pass through from outside into your home, while simultaneously allowing for waste to pass from your home to the outside. In most homes, traps are used to control the inflow of dangerous gasses into your water system, so expect to find a small number of them within your piping systems.

Trap price range: $20 – $100

Waste Outlet

A waste outlet or a drain-waste-vent is a system most commonly installed in and around your toilet. It uses gravity to pull waste down to the sewer, providing a clear channel for your waste to be disposed of. The outlet will usually be connected by a trap which will ultimately prevent any harmful substances from affecting your own water supply while maintaining a constant neutral air pressure that helps to move water through the system.

When it comes to the waste outlet, these are the common material types to choose from:

  • ABS, or Acrylonitrile, Butadiene, Styrene 
  • Brass 
  • PP, or Polypropylene 
  • PVC, or Polyvinyl Chloride 

Retaining Nut

The retaining nuts are the locking nuts that fasten your fixtures to the wall. In the case of your bathroom, they are the nuts that hold your bathtub or faucet in place. Usually installed on a shaft or elongated piece, the retaining nut prevents any further movement of your bathtub or sink even when tremendous force is applied.

Retaining nut price range: $50 – $20

Decorative Panel

Typically flush with your wall, the decorative panel is an outer layer of a wall that covers all the interior pipe make up of your bathroom. Generally, this takes the appearance of tile or natural stone, but it is also sold in a variety of materials such as acrylic which is much cheaper. The panel’s job is to hide many of the inner workings of the bathtub or sink from public view, providing a much cleaner bathroom aesthetic. They also need to be waterproof as well to prevent buildup and deterioration down the line.

Decorative panel price range: $10 – $300

tile grey variant


The lining refers to the area where your bathtub meets the joined wall, securing it. Problems with the lining usually arise from water seeping into the crevices along the side, causing it to deteriorate over time if untreated. The cure for this is to either install new lining, which consists of multiple layers of PVC plastic or acrylic which is then glued on top of your old bathtub then secure it with sealant. Or, you may need to replace your bathtub altogether.


There are many different faucets to choose from, but your choice will mostly depend on the type of bathtub you have.

Lever and Handle

The lever and handles determine your overall water pressure from your shower or bathtub. In many homes, the lever action is integrated into the handles, requiring you to pull outwards for there to be an inflow of water, which is useful for controlling your water levels. The other function these serve is to control the temperature of the water that comes out of your shower/bathtub.


The dome is the cover to your shower, allowing for a more controlled burst of water rather than a high pressure stream. Usually, a dome will have several holes dotted along its surface, which allow it to strain incoming water into a more manageable area.


A faucet cartridge is a type of valve that is located inside of your faucet that regulates water flow and temperature when you turn the handle. Located in many showers, it provides higher control of temperature and is usually the first thing to check when temperatures aren’t working optimally in your shower/faucet.

Faucet Spout

The faucet spout is the area where water flows from, or more specifically, where all the water pressure and piping directs your water to flow out of. So when you turn your faucet or sink handles, water will come out so long as your piping is hooked up properly. The spout also functions as a way of controlling outflow water as it’s angular and higher design means that the water pressure will be lessened having to travel upwards than if it was closer to the ground.

Now that you understand all the parts of a bathtub, you can better diagnose and resolve any issues that may arise in the future.

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Mateo Kennedy
4 years ago


I will like to place orders for some of your products, I will like to know if i can place orders with my credit card and if i can arrange pick up from your store/warehouse by a private freight company.

Get back to me at:
I will be looking forward to your quick response soon.

Mateo Kennedy

2 years ago

Thanks for this great article.

Stone Resin bathtubs starting at $2,940

Free material samples and tub templates

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