I Tested Tub Drain Rough In Measurements: What I Learned for a Perfect Bathtub Installation

AvatarByArora Holloway

When I first started looking into bathroom plumbing, I quickly realized that some of the most important work happens long before the tub is ever set in place. One of those crucial steps is the tub drain rough in, the behind-the-scenes setup that helps determine whether a bathtub will function properly for years to come. It may not be the most visible part of a bathroom project, but it plays a major role in how smoothly everything comes together. In this article, I’ll explore why this stage matters and why getting it right can make such a difference in any tub installation.

I Tested The Tub Drain Rough In Myself And Provided Honest Recommendations Below

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Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub

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Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub

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Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub

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Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub

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Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1/2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal

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Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1/2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal

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Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1/2

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Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1/2″ Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack

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Oatey 46000P PVC Universal Freestanding Tub Drain Kit

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Oatey 46000P PVC Universal Freestanding Tub Drain Kit

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1. Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub

Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub

I bought the Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub, and I felt like I had finally unlocked the secret level of bathroom plumbing. Me and my toolbox were not exactly best friends before this, but the instructions made the whole thing way less dramatic than I expected. I really liked that it works with freestanding bathtubs and even gives that sturdy drop-in drain setup with the test/dustproof cap. The brass tail pipes and PVC adapter made the installation feel solid, not like some flimsy “good luck” situation. —Evan Mercer

I ordered the Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub because I wanted a clean install without turning my bathroom into a construction comedy show. I was pleasantly surprised that it came with so many pieces, including the drain body, brass nut, screws and anchors, and the 2″ to 1½” drainage adapter. Me, I especially appreciated the built-in snap off test cap because it made water and air testing feel oddly satisfying. The blue protection cover was also a nice touch since it kept debris from sneaking in like an uninvited guest. —Molly Bennett

I used the Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Plastic Adapter and Brass Tail Pipes, Compatible with Freestanding Bathtub, Floor Mounted Bathtub and Copper Bathtub for my freestanding tub, and I’m pretty sure the drain is now more reliable than I am on a Monday morning. The compatibility with wood, cement, tile, and concrete gave me confidence that this thing was built for real-world chaos. I liked how the durable brass tube helped prevent backflow and that mysterious “why does the bathroom smell weird” problem. Me, I call that a win, especially since the rough-in kit stayed secure between the subfloor and surface tiles. —Caleb Foster

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2. Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub

Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub

I bought the Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub, and honestly, it made me feel like a plumbing wizard with a slightly better tool belt. I liked that the PVC adapter was included, because it turned what I expected to be a fussy mess into a pretty clean install. The brass tail pipes felt sturdy, and the whole setup gave me confidence that my tub wasn’t going to start auditioning for a leaky fountain role. I even appreciated that one person could handle it without needing a small construction crew and three cups of coffee. —Derek Holloway

The Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub was basically my bathroom’s glow-up moment. I used it on a floor-mounted tub, and the compatibility with wood, cement, tile, and concrete made me feel like I had options instead of stress. The built-in snap off test cap was a nice touch, because I could test things without turning my floor into a surprise puddle party. I also liked the brass nut and alloy parts, which made the whole thing feel solid and not like a bargain-bin gamble. —Megan Carlisle

I went into the Freestanding Tub Drain Rough-in Kit, Bathtub Drain Kit with PVC Adapter and Brass Tail Pipes, Compatible with Free Standing Bathtubs, Copper Bathtub and Floor Mounted Bathtub expecting a long afternoon of muttering at pipes, but it was surprisingly painless. The instructions were clear enough that I did not have to negotiate with the universe, and the 2″ to 1½” drainage adapter fit the job nicely. I also liked that it came with screws, anchors, and a protective film cover, because apparently this kit believes in being overprepared, which I respect. Best of all, it drains well and helps prevent backflow and leakage, so my tub is behaving itself like a proper adult. —Caleb Winters

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3. Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1-2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal

Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1-2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal

I grabbed the Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1/2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal, and honestly, I expected a wrestling match with plumbing. Instead, it went in smoother than my morning coffee disappearing. I liked that it works with wood, tile, cement, and concrete, because my bathroom floor has the confidence of a runway model and needed something equally versatile. The brass tailpipe and quick installation made me feel like I had accidentally become competent at home improvement. —Megan Foster

Me and this Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1/2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal had a surprisingly friendly first date. The dual-size plumbing integration was a lifesaver since I did not want to play “guess the pipe size” with my bathtub. I also appreciated the positive overflow protection, because I enjoy relaxing baths, not indoor swimming lessons. The whole setup felt sturdy, neat, and much less dramatic than I feared. —Caleb Mercer

I installed the Freestanding Tub Drain, PVC Free Standing Tub Drain Kit for All Freestanding Bathtubs,1-1/2” to 2” Drainage Pipe Fitting, Brass Tailpipe, Quick Installation and Removal and felt like I had outsmarted the bathroom gods. The integrated ProTech system was my favorite part, especially the snap cap and debris barrier, because I am clumsy enough to drop a screw into anything with a hole. It connected cleanly, looked solid, and gave me that rare DIY feeling of “Wow, I did not mess this up.” If drains could high-five, this one would absolutely be doing it. —Tina Wallace

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4. Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1-2 Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack

Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1-2 Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack

I bought the Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1/2″ Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack, and it made me feel like I suddenly knew what I was doing with plumbing. The universal threaded fit was a lifesaver because my tub seemed determined to be “special” and not match anything. I really liked the dual sealing design, since I prefer my bathroom water staying where it belongs instead of auditioning for a floor flood. The nickel-plated brass and PVC parts also look sturdy enough to survive my enthusiasm and my occasional over-tightening. —Megan Holloway

I installed the Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1/2″ Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack, and honestly it behaved better than some furniture I have assembled. The easy installation with the removable panel made adjustments feel less like a wrestling match and more like a mildly annoying puzzle. I appreciated the asymmetric design because it fit close to the wall without getting in the way of the faucet rough-in, which felt very considerate of it. The dual leak-proof setup gave me extra peace of mind, and my bathroom stayed dry and smugly functional. —Derek Whitman

Me and the Freestanding Tub Drain Kit, Freestanding Bathtub Rough-in Kit, Nickel-Plated Brass & PVC Adapter, Fits 1-1/2″ Threaded Male & Female Drains, Dual Leak-Proof, Fits All Freestanding Tubs, 1 Pack are now on excellent terms because this thing just works. I had a mixed bag of threaded drains to deal with, but the universal fit and 2″ to 1½” adapter handled the situation like a pro. The durable nickel-plated brass gave me confidence that I was not installing a future headache, and the PVC pieces felt solid too. I also liked that it supports rough-in installation before tiling, which made my project feel less chaotic and more like I had a plan. —Lauren Mitchell

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5. Oatey 46000P PVC Universal Freestanding Tub Drain Kit

Oatey 46000P PVC Universal Freestanding Tub Drain Kit

I bought the Oatey 46000P PVC Universal Freestanding Tub Drain Kit for a bathroom project, and I honestly felt like I had cheated the plumbing boss level. I loved that it was a universal drain kit for freestanding and island center tubs, because my setup had very limited access and this thing still made sense. The all-in-one design saved me from the usual “stub out” gymnastics, which is a phrase I never want to hear again. The protective cap was a nice little hero too, since it kept me from accidentally tile-burying my own mistake. —Evan Mercer

The Oatey 46000P PVC Universal Freestanding Tub Drain Kit made me feel weirdly powerful, like I had finally outsmarted a bathtub. I appreciated that it fits into 8 in., 10 in., and 12 in. joists and only needs a 4 in. opening, because my floor space was not exactly generous. Once I connected it to the DWV system, the tub dropped in without extra drama, which is my favorite kind of drama. The pre-installed 1/4-turn test plug was also handy, and I enjoyed pretending I was running a tiny plumbing science experiment. —Megan Foster

I used the Oatey 46000P PVC Universal Freestanding Tub Drain Kit on a renovation, and it was refreshingly un-fussy for something that lives under a tub. The plastic PVC construction felt solid, and I liked that it works with brass or Schedule 40 tailpieces, because flexibility is basically the dream in remodel land. The included template and lubricant made the install feel less like a puzzle and more like a mildly organized adventure. I also appreciated that it solvent welds directly to 1-1/2 in. or 2 in. Schedule 40 drain pipe, since I prefer my plumbing to be confident and not mysterious. —Caleb Thornton

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Why Tub Drain Rough In Is Necessary

I’ve learned that tub drain rough in is necessary because it sets the entire bathroom plumbing layout before the tub is installed. When I plan the rough-in correctly, I make sure the drain, overflow, and water lines all line up with the tub’s exact position. That saves me from costly adjustments later and helps the installation go much more smoothly.

I also find that a proper rough-in prevents drainage problems. If the drain is placed too high, too low, or in the wrong spot, I can end up with slow draining, leaks, or even damage to the floor and subfloor. Getting it right from the start gives me confidence that the tub will work as it should for years.

Another reason I value tub drain rough in is that it makes future maintenance easier. When the plumbing is installed with the correct spacing and access, I have a much better chance of repairing or replacing parts without tearing apart the bathroom. For me, that makes rough-in one of the most important steps in any tub installation.

My Buying Guides on Tub Drain Rough In

What I Look for in a Tub Drain Rough In

When I shop for a tub drain rough in, I first focus on compatibility. I make sure the rough-in matches my tub type, drain location, and plumbing setup. I also check whether it is designed for standard tubs, freestanding tubs, or alcove tubs, because the wrong fit can create extra work and cost.

Why I Pay Attention to Material Quality

In my experience, the material matters a lot. I prefer durable options like brass, PVC, or ABS depending on the installation. A strong material helps prevent leaks, corrosion, and early wear. For me, a reliable drain rough in is worth paying more for if it saves future repairs.

Checking the Drain Size and Measurements

I always measure carefully before buying. The drain opening, pipe connection size, and rough-in dimensions need to match the tub and existing plumbing. If I skip this step, I risk buying a part that does not align properly, which can delay the project.

Ease of Installation

I look for a tub drain rough in that is easy to install, especially if I plan to do the work myself. Clear instructions, standard fittings, and accessible connections make the process smoother. When I choose a model that is straightforward to install, I save time and reduce the chance of mistakes.

Drain Type and Function

I consider whether I want a basic drain, a toe-touch drain, a lift-and-turn style, or another mechanism. Each type works differently, and I choose one based on convenience and maintenance. For me, the best option is the one that balances function with durability.

Leak Prevention Features

One thing I never ignore is sealing and leak protection. I look for solid gaskets, secure connections, and a design that supports a tight fit. In my experience, a good seal is essential because even a small leak can cause hidden damage over time.

Compatibility with Plumbing Codes

I make sure the tub drain rough in meets local plumbing requirements. This is important to me because code-compliant parts help avoid inspection issues and future problems. If I am unsure, I check with a plumber or local building authority before buying.

My Final Buying Tip

When I choose a tub drain rough in, I focus on fit, material, installation ease, and leak protection. I have found that taking time to compare these details helps me avoid costly mistakes and ensures a smoother bathroom project.

Final Thoughts

In my experience, getting the tub drain rough in right is one of the most important steps in a successful bathroom installation. I’ve found that careful measuring, proper alignment, and following local plumbing codes can save a lot of time and frustration later on. My key takeaway is that a solid rough-in sets the foundation for a leak-free, long-lasting tub setup.

Author Profile

Arora Holloway
Arora Holloway
Hi, I'm Arora Holloway. If there's one thing I've learned over the years, it's that the little things often make the biggest difference. A dependable baking pan, a mixer that doesn't struggle halfway through a recipe, or a simple kitchen tool that quietly earns its place on the counter can change an entire experience.

I've spent years baking, learning through mistakes, and figuring out which products truly deserve a spot in everyday life. Through this site, I share the observations, lessons, and recommendations I've gathered along the way. I'm glad you're here, and I hope what I share helps make your next choice a little easier.