Common Toilet Buying Mistakes You Need to Avoid
Buying a new toilet sounds simple until you start shopping. Dozens of models look more or less the same, but small differences in size, shape, and design decide whether a toilet fits perfectly or has to be returned, or worse, installed anyway and lived with for years.
Ben, a plumber with One Tom Plumber, walks through the most common mistakes homeowners make when buying a toilet. Here is what to check before you buy. For more bathroom guides, see our bathroom remodeling guide.
Mistake #1: Getting the Wrong Rough-In Size
The most common mistake is overlooking rough-in size: the distance from the wall behind the toilet to the center of the drain, marked by the bolts that anchor the toilet to the floor. It is set by your bathroom’s existing plumbing, not by the toilet you pick.
Before shopping, measure from the wall to the center of one of the closet bolts holding your current toilet down, and compare it with the rough-in listed for the new toilet. If the new toilet’s base is shorter than the distance from the rear bolt holes to the wall, it should fit.
The standard rough-in in most homes is 12 inches, but older homes may have a 10-inch or 14-inch rough-in. Buying a 12-inch toilet for a 10- or 14-inch setup is one of the fastest ways to end up with a toilet that won’t install correctly. Moving the drain to change the rough-in is a plumbing job; our bathroom plumbing cost guide covers what moving a toilet costs.
Mistake #2: Choosing the Wrong Bowl Shape
Toilets come in two bowl shapes. Elongated bowls are longer and egg-shaped, and most people find them more comfortable. Round bowls take up less space, which makes them practical in small bathrooms and tight installations.
There is no universally correct choice; match the bowl to the space you have and your own comfort before committing to a model.
Mistake #3: Ignoring Seat Height
Standard toilets have a seat height of about 14.5 to 15 inches. Comfort-height models are taller, which helps taller adults and anyone with knee, hip, or balance issues; Ben describes them as about 16 to 17 inches, and ADA-compliant comfort height is 17 to 19 inches to the top of the seat.
Think about who uses the bathroom most and which height will be comfortable for them. It is one of the easiest specs to check and one of the easiest to overlook. Our aging-in-place bathroom remodel guide covers comfort-height toilets alongside grab bars and other safety features.
Mistake #4: Picking the Wrong Design Style
There are three common toilet configurations, each with trade-offs in cost, installation, and appearance:
Style | Cost | Installation | Cleaning and look |
|---|
Two-piece (separate tank and bowl) | Typically the most affordable | Standard | By far the most common; a seam between tank and bowl collects grime |
One-piece | Usually costs more | Standard | Seamless, so easier to clean |
Wall-mounted | Usually the most expensive | Hardest: needs a drain and reinforced support built into the wall | Doesn’t touch the floor; many consider it the most striking look |
Beyond looks and installation, there is no major functional difference among the three, so choose based on your budget, your plumbing, and the look you want.
Mistake #5: Skipping a Quality Toilet Seat
The seat is one of the most frequently used surfaces in the home, so it is worth choosing a well-made one rather than whatever is cheapest or comes bundled. Match it to the bowl shape (round or elongated) and to the color and style of the bathroom.
Mistake #6: Buying an Off-Brand Toilet
Saving money is a reasonable goal, but an unfamiliar off-brand toilet can cost more in the long run. Name-brand toilets tend to be better built, and replacement parts for major brands are far easier to find.
Well-established brands include Toto, American Standard, and Kohler. Choosing an established brand doesn’t mean spending the most; it means a track record and accessible replacement parts. Our guide to buying bathroom plumbing fixtures covers how quality varies between stores and models.
Mistake #7: Not Considering a Water-Saving Toilet
Toilets can account for up to roughly 30 percent of a household’s indoor water use, so efficiency is worth weighing alongside size and style. Newer flushing technology, especially dual-flush systems, can cut water use substantially compared with older single-flush models without sacrificing performance.
Final Thoughts
Buying a toilet involves more decisions than it first appears: rough-in size, bowl shape, seat height, style, seat quality, brand, and water efficiency all decide whether you are happy with it or dealing with a return, an awkward fit, or repair headaches. Measure your existing setup and compare these seven factors before you buy.
If the toilet is part of a larger update, our look at bathroom trends for 2027 covers where fixtures and finishes are heading.
When you are ready to get estimates from licensed contractors in your area, contact Home Upgrade Pros or call: (725) 677-8878 to connect with professionals who offer free no-obligation assessments.
Frequently Asked Questions
What is toilet rough-in size, and why does it matter?
Rough-in size is the distance from the wall behind the toilet to the center of the drain, marked by the closet bolts. It matters because it is set by your existing plumbing, not by the toilet you choose; buying for the wrong rough-in is one of the most common reasons a new toilet won’t install properly.
What is the standard toilet rough-in size?
Most homes have a 12-inch rough-in, though older homes sometimes have 10 or 14 inches. Always measure your existing toilet before shopping.
Round or elongated toilet bowl — which is better?
Neither is universally better. Elongated bowls are generally considered more comfortable, while round bowls take up less space and suit smaller bathrooms.
What is a comfort height toilet?
A taller toilet that makes sitting and standing easier. ADA-compliant comfort height is 17 to 19 inches to the top of the seat, compared with about 14.5 to 15 inches for a standard toilet; some models marketed as comfort height are about 16 to 17 inches.
Is a one-piece or two-piece toilet better?
It depends on your priorities. Two-piece toilets are the most common and usually the most affordable. One-piece toilets cost more but are seamless and easier to clean. Beyond cost and cleaning, there is no major functional difference.
Are wall-mounted toilets worth it?
They usually cost the most and are the hardest to install, because they need a drain and reinforced support in the wall. They are worth it mainly if the look and the floor space they free up matter to you.
Does toilet brand actually matter?
Yes. Established brands tend to be better built, and their replacement parts are far easier to find. Off-brand toilets can be cheaper up front but harder and slower to repair.
How much water can a dual-flush toilet actually save?
Toilets can account for up to roughly 30 percent of indoor water use, and dual-flush systems can meaningfully reduce that compared with older single-flush models. Exact savings depend on the model and what you are replacing.
What toilet seat should I choose?
Choose a seat that matches the bowl shape and coordinates with the bathroom’s color and style. Because it is used so often, a quality seat is worth the small extra cost.
What is the biggest mistake people make when buying a toilet?
Overlooking rough-in size. It is the one measurement that decides whether a new toilet will fit your plumbing, so measure your current toilet before you shop.
