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The bathtub is the centerpiece of the bathroom, but buying one during bathroom renovations can be stressful. With a seemingly infinite number of style options and material types, worrying about the hardware that comes with a bathtub is the last thing you want to do. So, when you purchase a bathtub, does it come with a drain? Do all bathtubs use the same type of drain? We've done the research and have the answers to help you make the best bathtub purchases.
Generally, bathtubs are sold without drains and faucets but include pre-cut holes for both. Fortunately, most standard bathtubs have the same size drains, which are 1.5 inches wide.
That's the surface-level information on bathtubs and bathtub drains, but there are many factors to consider when purchasing and installing a drain. In the rest of the post, we will discuss the nature of drains, the cost associated with drain installation, and when you might want to install them.
Bathtubs And Their Drains
Most bathtubs sold on the market are pipeless and drainless tubs. However, there are some kits available that include the tub plus all necessary piping. These kits sometimes include doors for shower and bathtub combination units. Even though these kits include everything, they still need to be put together manually.
For example, the bathtub without a drain in the image below is being sold on Amazon. Lowes, Home Depot, and other hardware stores also have bathtubs like this available.
Are there different size bathtub drains?
Even though you'll most likely have to purchase the drain separately from the tub, rest assured knowing that all bathtub drains are made to fit the industry-standard size bathtub drain holes. The drain pipe width is standard in the manufacturing and plumbing industry, making installation and maintenance easier for all parties.
The width of the drain has to match the width of the hole of the bathtub, it also has to fit into the section of pipe beneath the tub that connects the bathtub with the rest of the household plumbing. The industry standard size is 1.5 inches wide on all regular bathtubs.
Hardware stores and online marketplaces commonly sell replacement drains that are universal and fit the standard-size bathtub.
Can a bathtub drain be replaced?
There are two situations when you will run into having to purchase a drain for a bathtub. You will be either installing a bathtub into a brand new bathroom or replacing an old bathtub in an existing bathroom. But can you replace a drain without having to replace the entire bathtub?
There are situations where a drain needs to be replaced, and the bathtub does not. The silicon or rubber seal in the part that connects to the bathtub may fail, or leaking might start in the joints. In the case of faulty piping or a poor-quality drain, your bathtub might outlive your drain, inspiring replacement. Please remember to always consult a professional before altering pipes or drywall in your bathroom.
How much does a bathtub drain cost?
When specifically purchasing the drain for your bathtub installation, expect a price of around $35. There are various affordable options available, most of them being plastic with chrome or brass screws and accents. Here are a few available drain kits:
The first is the Danco Lift and Turn Bath Drain Kit, which has the standard 1.5-inch wide drain piping and will fit nearly any bathtub. This replacement kit includes everything needed to replace an old drain pipe in your bathtub.
The next drain is the Westbrass Tubular Tip Toe Bath Waste Drain Kit, which also includes everything needed for a drain replacement. This kit features insert assembly, making installation relatively easy.
Each of these kits may require cutting pipes to fit a tub vertically to ensure the overflow drain at the top is in the correct position. But they are both universal and will fit the standard bathtub.
The drain is only part of the whole bathtub system, which is a lot more expensive to install than $35. To replace an entire bathtub and piping, it will cost around $1,000, excluding professional labor from a plumber. That being said, this doesn't mean you can't improve their current bathtub with small upgrades like a drain replacement.
For more information on replacing an entire bathtub, please read our post titled "How Much Does it Cost to Replace a Bathtub?"
Parts of a Bathtub Drain System
The drains pictured above are only the above-ground, or bathtub level, sections of the complete drain system. It is important to understand the other parts that go into removing water from the bathtub, and consequently the house, before proceeding with any work.
The part of the drain that we are most familiar with is the hole in the bathtub that opens down into the drain shoe. From there, a short, horizontal pipe leads to another vertical pipe, called the overflow pipe. The overflow pipe is in the upward direction from that connection point. Next, a second drain comes out of the overflow pipe in the upper part of the tub.
In the opposite, downward direction from the connection point, you will find the curved pipe called the trap. This portion of pipes leads the drained water out of the bathroom and into the sewage system.
Do all bathtubs have an overflow drain?
Most standard bathtubs have an overflow drain. Depending on where you live, some building codes even require bathtubs to have overflow drains. Bathtub overflow drains are similar to the overflow drains found in most sinks and even inside toilets. The overflow pipe is the secondary drain that will allow excess water to flow down the vertical pipe. This is necessary if the main drain shoe opening is covered and the water level gets too high from a slow flow of water from the faucet.
What kind of trap do you use for a bathtub?
As mentioned above, bathtub drains contain a U-shaped curve in their piping that leads to the sewer lines. The specific trap in a bathtub is called a P-trap, and its primary function is to prevent any gases from escaping the lower pipes into your bathroom. Sinks and toilets also contain trap pipes.
The trap pipe serves other purposes aside from keeping potentially toxic sewer gas from getting into your bathroom. The bathtub P-trap helps keep clogs centralized, making them easier to be cleaned. On the other hand, if you were to drop something like a ring in the drain, it will get stuck in the P-trap and won't make its way into your city's sewer network. P-traps serve the same function in sinks.
Most bathtubs do not come with pre-installed drains, but that's okay because drains themselves are very affordable. You may have reason to replace your drain for some immediate improvements to your bathtub. If you do, the standard size will make it much easier, and the knowledge gained here may help you diagnose any other bathtub problems. If you do need to buy a completely new bathtub, make sure you purchase a drain as well.
Lastly, please check out our other bathtub related posts while you're here: