Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
You will touch your toilet every day for the next decade, so the wrong pick means years of wobbling seats, mystery leaks, and scrubbing that ugly seam where a separate tank meets the bowl. Before you buy, check three things: whether the rough-in measurement (the gap from the wall to the center of your floor drain) matches your floor, whether the seat height suits the people using it, and how well the flush actually clears the bowl.
I’m Mohammad Maruf — the founder and writer behind KitchPrep. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Every toilet below is a true one-piece design: the tank and bowl are molded as a single smooth unit, so there is no gasket between them to leak or collect grime.
Our Picks at a Glance
How To Choose The Best 1-Piece Toilet
Three numbers decide whether a toilet fits, feels right, and stays clean: the rough-in distance, the seat height, and the flush score. Get those wrong and no amount of style saves the install.
Measure the rough-in before anything else
The rough-in is the distance from the finished back wall to the center of the floor drain. Most homes use 12 inches, but small bathrooms and older builds often sit at 10 inches. A 12-inch toilet forced onto a 10-inch rough-in simply will not seat against the wall, and a 10-inch unit leaves an awkward gap on a 12-inch floor. Buyers report measuring twice pays off — the HOROW T0338W10 exists specifically for the tighter 10-inch layout.
Decide on seat height
A standard-height bowl sits around 15 to 17 inches from floor to rim, while chair-height models — often called ADA height — measure closer to 17.3 inches. That extra lift means less bending for taller adults, seniors, and anyone with knee or hip discomfort. If children or shorter users share the bathroom, the taller seat can feel less natural, so weigh who uses it most.
Understand the flush
A MaP score measures how many grams of waste a toilet clears in a single flush; 1000 grams is the top mark many models hit, while 800 grams is still solid. Dual-flush toilets let you pick a light flush for liquids and a heavier one for solids, cutting water use without giving up clearing power on the tough jobs.
Quick Comparison
| Model | Best For | Flush Type | Seat Height | MaP Score | Amazon |
|---|---|---|---|---|---|
| HOROW T0338W★ Best Overall | Small bathrooms | Dual 1.1/1.6 GPF | 17.3″ ADA | 1000g | Amazon |
| Casta Diva CD-T005Best Water Saver | Water savings | Dual 1.1/1.6 GPF | 17″ ADA | 1000g | Amazon |
| DeerValley DV-1F026Rimless Wonder | Everyday value | Dual 1.1/1.6 GPF | 16.875″ | 800g | Amazon |
| DeerValley DV-1F52807 | Tiny powder rooms | Single 1.28 GPF | Standard | — | Amazon |
| HOROW T0338W10 | 10″ rough-in spaces | Dual 1.1/1.6 GPF | 17.3″ ADA | 1000g | Amazon |
| Ivy Dual Vortex | Bold black styling | Dual 1.1/1.6 GPF | Standard | — | Amazon |
| SOTOMO MY-2133 | Compact round bowls | Dual 1.1/1.6 GPF | 16.5″ | — | Amazon |
| WOODBRIDGE T0001-MB | Matte black accents | Dual 1.28 GPF | Chair height | 1000g | Amazon |
| American Standard Champion 4 | Clog-free reliability | Single 1.6 GPF | 16.5″ | — | Amazon |
In‑Depth Reviews
1. HOROW T0338W One Piece Toilet with ADA Chair Height 17.3″, Dual Flush
Our pick — 4.5★ from 950+ verified ratings; the strongest balance of quality and price.
The compact powerhouse that squeezes full comfort into a tiny footprint.
If your bathroom is tight, this is the one to beat. The HOROW T0338W measures 26.6″D x 15″W x 26″H, a footprint small enough for a powder room yet built around a comfortable elongated bowl. The one-piece construction means no seam between tank and bowl, so there is nowhere for grime to collect and nothing to wobble loose over time.
You bend less when you sit and push up because the seat sits at 17.3 inches — chair height, a few inches higher than a standard bowl. Owners mention it was the deciding factor: “Replaced 40-year-old toilet; needed ≤26″ tall for small bathroom.” That 26-inch ceiling is why this model wins so many small-space jobs. The dual 1.1/1.6 GPF siphon flush pairs a fully-glazed 2-inch trapway with a 1000-gram MaP score, so it clears waste on the light setting without a second flush.
The installation is where expectations need calibrating. The toilet weighs 99.2 pounds, so plan for two people to lift it, and the side access holes are narrow enough that tightening the floor bolts takes patience. Several owners note that compact 1/4-turn shut-off valves behind the toilet help. It ships with the wax ring, floor bolts, and pre-installed flush valve, and the soft-close seat is screw-fixed so it will not drift. Compact height, chair comfort, and a 1000-gram flush score — this is the version of a one-piece toilet that fits real homes.
Why owners stick with it
- 26-inch height fits tight spaces, matching listings like the American Standard Champion 4’s 29.5-inch height problem for small rooms
- 17.3-inch ADA chair height eases sitting and standing for seniors and taller adults
- MAP 1000g dual flush clears waste without wasting water
The reality check
- At 99.2 pounds, plan on two people and budget extra time for bolt access
- The narrow side holes make tightening the floor nuts fiddly without a deep socket
Grab this if: your bathroom is under 30 inches front-to-back and you want chair-height seating, a 1000g flush, and a smooth one-piece body without moving to a full-time flip.
Measure first: confirm your rough-in is 12 inches, because a 10-inch layout will need the T0338W10 version instead.
2. Casta Diva Elongated One Piece Toilet with 17″ Comfort Chair Height Seat
A CUPC-certified one-piece that flushes 1000 grams while sipping 1.1 gallons.
Where the HOROW T0338W leans compact, the Casta Diva leans luxurious. It is a skirted one-piece built around an elongated bowl, with the tank integrated so there is no separate tank-to-bowl gasket to leak. The skirt hides the plumbing and smooths the exterior — you simply wipe it down without hunting crevices. For a bathroom where guests notice the fixture, this presents quietly well.
The flush carries real weight: it holds a MAP 1000-gram rating (a lab measure of waste cleared in one flush) with a fully-glazed trapway (the smooth internal waste channel), and the dual-flush sets up at 1.1 GPF for liquids and 1.6 GPF for solids — a combination that earns the WaterSense label (an EPA marker for water efficiency). Customers note it as: “Strong flush on both 1.1/1.6 GPF settings, clears bowl effectively; sleek one-piece, 17″ ADA comfort height, solid.” The seat sits at 17 inches, softer on shorter users than the DeerValley DV-1F0437’s 17.5-inch height, and the soft-close lid comes off with a quick-release button for deep cleaning.
The catch is installation patience. The drain layout sits close to the wall, so a standard long-handled shut-off valve can foul the tank — a compact 1/4-turn valve is the fix several installers reach for. One dissenting owner struggled with recurring clogs, but that sits against a body of feedback where flush power is the consensus strength. It ships as a standard 12-inch rough-in with a pre-installed fill and flush valve, wax seal, and all hardware. If water bills matter and you want a 1000g flush in a clean skirt, this does it gracefully.
Where it shines: The WaterSense dual-flush and 1000-gram MaP score pair water savings with reliable clearing — the version of a one-piece most likely to lower a utility bill.
The install note: When swapping in this model, choose a compact 1/4-turn shut-off valve to fit the tight rear clearance instead of a standard lever valve.
Reach for this if: you want a CUPC-certified, WaterSense one-piece that flushes hard and saves water, and you value a fast-release seat for cleaning.
Look elsewhere if: your rear wall clearance is genuinely cramped or you need a 10-inch rough-in — a 12-inch model simply clamps to the wall.
3. DeerValley Elongated One-Piece Toilet with ADA Chair Height Seat, DV-1F0437
A standard-height skirted one-piece that dozens of owners call a straight upgrade.
This one runs a step shorter than the chair-height crowd. The DeerValley DV-1F026 sits at 16 7/8 inches, so it fits under a window or low shelf that a 17.5-inch bowl would not. It is a skirted one-piece, and its two big side openings make hiding the floor bolts simple — the smooth exterior wipes clean without chasing hidden corners. It ships with a pre-installed soft-close seat and a slow-close lid.
Its dual 1.1/1.6 GPF flush pushes through a fully-glazed 2-inch trapway but scores 800 grams on MaP, below the 1000-gram models above. That is a step under the 1000g jobs at the top of this list, so if clogs are a daily battle at home, a higher MaP model is the safer move. For an averaged household it flushes cleanly, and owners note it uses minimal water. Chair-height conversions from the standard 15- to 17-inch range — like this one — often become an upgrade story: reviewers point out it as a definite step up from builder-grade fixtures.
Weigh it against the HOROW T0338W and you trade a taller seat for a lower profile. The internal fill and flush components are integrated rather than exposed, so a repair means service access rather than a quick tank swap — worth knowing before you commit. But for a reasonably sized bathroom where a standard seat fits the family better than chair height, this is the calm, sensible choice that just works.
What buyers latch onto: The smooth one-piece look at a modest profile — a fully skirted exterior (a smooth cover that hides the trapway) that stays clean and a soft-close seat included in the box.
The honest limit: MAP 800 grams means heavy loads may take a second flush, so households that heavy-use a single toilet should compare against a 1000g model.
Reach for this if: you want a standard-height, skirted one-piece that fits under a shelf, flushes quietly, and comes with the seat and slow-close lid ready to go.
Look elsewhere if: your family needs a 1000-gram MaP flush — this model’s 800-gram rating leaves a little less headroom on the tough jobs.
4. DeerValley Compact One-Piece Toilet 1.28 GPF Single Flush Fully Skirted Bowl
When four inches of floor space is the whole difference, this is the one.
The motto for this DeerValley is blunt: it takes the least room of anything here. At 23.5 inches from back to front, it is the shallowest one-piece in this roundup, which matters in a half bath where the door swing or the tub edge crowds the bowl. One reviewer noted it gained 4 inches of space to the tub, effectively converting a cramped corner into a usable bit of floor. The single 1.28 GPF siphon flush qualifies for many local utility rebate programs that reward high-efficiency toilets.
Beyond the number, it does the awkward job well. The fully-glazed 2 3/8-inch trapway reduces clog risk and the skirted design wipes clean in one pass. It ships as a standard-height fixture with a soft-close seat and quick-release hinges so you can pop the seat off for deep cleaning. The single-flush format means there is no lighter setting to fuss over, which some buyers prefer for simplicity.
The real trade-off is water. At 1.28 GPF and standard height, it clears everyday waste without drama but leaves a little less margin than a dual 1.6 GPF model when the load is heavy — it is a space-saver first. There is also no built-in bidet, and owners with a separate bidet seat report the bowl shape needs a slim-fit unit. If your bathroom is measured in inches rather than feet, this is the toilet that finally fits.
Where it wins: The shortest back-to-front depth of anything in this list — a standard-height bowl that reclaims floor in a tiny half bath and qualifies for efficiency rebates.
The space-rate trade-off: A single 1.28 GPF flush is gentler on heavy loads than a dual-flush 1.6 GPF, so this is a room-first choice rather than a flush-power champion.
Reach for this if: your half bath is so tight that depth is the deciding spec, and you want a single-flush one-piece that earns efficiency rebates.
Look elsewhere if: you need maximum flush margin on heavy loads — the single 1.28 GPF setting has no heavier backup.
5. HOROW T0338W10 One Piece Toilet with ADA Chair Height 17.3″, Dual Flush
The 10-inch rough-in model that saves a bathroom the rest of the line cannot fit.
This is the same body as the Best Overall HOROW, retuned for the tightest layout in the house. The HOROW T0338W10 measures 26.6″D x 15″W x 26″H — a compact elongated body with a 10-inch rough-in, meaning the drain sits two inches closer to the wall than standard. If your existing toilet has a gap behind it or a 10-inch flange, this is the model built for you, and the 17.3-inch ADA chair-height seat keeps the same low-strain sit as its 12-inch sibling.
The same 1000-gram MaP dual flush at 1.1 and 1.6 GPF clears waste without a second pass. The trapway is fully glazed at 2 inches, and the soft-close seat is screw-fixed so it stays firmly planted rather than drifting sideways with use. That combination makes this a serious choice for anyone whose bathroom was built before the 12-inch standard, or for a 5-by-7 bath where every inch counts.
Installation requires the same patience as any heavy one-piece — it weighs 99.2 pounds and the side access holes are tight, so line up a helper and a deep socket. The bigger reality is that 10-inch rough-ins are less common, which is exactly why this unit is worth knowing about: it solves a fit problem most of the list cannot. If your floor drain is 10 inches from the wall, this is the one your bathroom has been waiting for.
Why this exists: A 10-inch rough-in with the same 1000-gram dual flush and 17.3-inch chair height as the top pick — made specifically for tight or older bathrooms.
What to expect: The compact 26.6-inch depth still needs two people to lift, and the side bolt access is a tight squeeze.
Reach for this if: your floor drain sits 10 inches from the wall and you want chair-height seating plus a 1000-gram dual flush without moving to a two-piece.
Look elsewhere if: your rough-in is 12 inches — the 12-inch HOROW T0338W fits that layout and installs with less margin to hit.
6. Ivy One Piece Toilet Dual Vortex Flush in Glossy Black 1.1/1.6 gpf
The glossy black statement piece that turns a bathroom fixture into a design cue.
Most one-piece toilets are white and want to disappear. This Swiss Madison Ivy does the opposite. The glossy black scratch-resistant ceramic is non-porous, so it wipes clean without staining, and the fully skirted trapway hides the plumbing behind a smooth shell for a look you do not normally see in this category. It measures 26.8″D x 13.4″W x 28.5″H, so it slips into narrow spots, and the elongated bowl gives adults extra room over a round seat.
“It is compact and functions well.” The button and trapway are fully glazed and the trapway is skirted, which means less surface for residue to catch.
The honest catch is the seat. Because the bowl is a standard height between 15 and 17 inches and the shape is shorter than a classic, some users report splash issues where the stream strikes the front — fine for some, not for others. The manufacturer does not include a bidet, so budget for a slim seat if you want one. As a design-forward centerpiece in a guest bath, it stands out precisely because it does not look like every other toilet.
The style anchor: A non-porous scratch-resistant glossy black one-piece with a skirted, fully-glazed trapway — the rare toilet chosen for how it looks as much as how it flushes.
The one caveat: The shorter bowl shape can cause splash for some users, so this is not the pick if you want a classic elongated contour.
Reach for this if: you are styling a modern bathroom and want a glossy black one-piece with dual flush, a skirted trapway, and 3-inch access holes for easier install.
Look elsewhere if: you prefer a classic taller profile — this standard-height bowl sits lower than the chair-height models at the top of this list.
7. SOTOMO MY-2133 Compact One-Piece Toilet, Space-Saving Round Bowl
A compact round bowl with a seat that feels a grade above its price point.
You can spot the difference the moment you touch the seat. Where many small toilets use a basic PP seat (polypropylene, a lighter plastic), the SOTOMO MY-2133 upgrades to a UF seat (urea-formaldehyde, a denser plastic) that is heavier, more scratch-resistant, and slower to yellow — a small detail that matters if you plan to keep the fixture for years. It pairs with a compact round bowl measuring 25″D x 13.4″W x 28.4″H, and the round shape shortens the reach, which helps in a powder room or under a low window.
Its dual flush pairs a 1.6 GPF full setting with a 1.1 GPF partial, averaging under 1.28 GPF. A 2-inch fully-glazed trapway reduces clog risk in older plumbing, and the Siphon Jet action clears normal waste without drama. The bowl sits at 16.5 inches, between a true standard and full chair height, and the quick-release seat hinges let you lift the lid off in a second for deep cleaning around the mount.
The catch is the round bowl itself. It is more compact than an elongated oval, so heavier users or anyone used to a long bowl will feel the difference in seating room. On the flip side, that round shape is why it tucks into spaces that a full-length model cannot. If you want a small-footprint toilet that does not feel cheap when you sit on it, the upgraded UF seat is the reason to look here.
The seat is the story: A durable scratch-resistant UF seat on a compact one-piece — a heavier, slower-yellowing grade of plastic that many small toilets skip.
The round-bowl note: A round bowl is shorter than the elongated bowls on most of this list, so buyers who want extra seating length should look at the elongated DeerValley models instead.
Reach for this if: you want a genuinely compact round-bowl one-piece with a premium UF seat and a dual-flush that saves water.
Look elsewhere if: you need the extended seating of an elongated bowl — this model trades bowl length for its tight footprint.
8. WOODBRIDGE T0001-MB One Piece Toilet with Soft Closing Seat, Chair Height
A 1000-gram flusher wearing a matte black button and ADA chair height.
If your bathroom already has matte black fixtures, the WOODBRIDGE T0001-MB matches the story. It is a skirted one-piece with a matte black-plated top button that pairs with brass or matte black hardware, and the bowl is set at chair height to meet ADA standards for easier sitting and standing. Its 1000-gram MaP score — matching the HOROW T0338W — runs through a fully-glazed skirted trapway, so it clears waste in one flush.
It also brings real certifications: it meets US UPC and Canada CSA standards and is WaterSense certified, meeting or exceeding ANSI Z124.1 and ANSI A112-19.7, and meeting the Massachusetts Plumbing & Gas Code. That is the paperwork some jurisdictions and inspectors actually check, so it matters if you are pulling a permit. It arrives all-in-one with the pre-installed soft-close seat, water fitting, wax ring, floor bolts, and even a special hand wrench for tight spaces.
There is one design quirk worth flagging: only the button is matte black. The seat hinges are a different finish, so if you are matching every detail to a matte black bathroom, the contrast is noticeable. Installation also requires a bit of planning — the toilet needs roughly 10 inches of side clearance, and one owner had to relocate the water line because the body is wider than a standard toilet. But for buyers who want a 1000-gram flush and a chair-height seat with a design accent, this is a strong pick.
The flush and the code: A MAP 1000-gram flush meets US UPC and Canada CSA standards, WaterSense certified, and meets ANSI Z124.1 and ANSI A112-19.7 — useful if the install needs to pass inspection.
Match the finish: Only the top button is matte black; the seat hinges are not, so plan around the contrast rather than fight it.
Reach for this if: you want a chair-height one-piece with a top-tier 1000-gram flush, code-compliant certifications, and a matte black accent that suits modern hardware.
Look elsewhere if: you want every visible fitting to share one finish, or your bathroom lacks 10 inches of side clearance.
9. American Standard Champion 4 One Piece Elongated Toilet, 1.6 GPF
A large 4-inch flush valve and a 10-year warranty built for one job: no plunging.
If clogging is the complaint your old toilet has earned, this is the American Standard building its case around it. The Champion 4 pairs a 4-inch (102 mm) flush valve (the opening that releases water) with a 2 3/8-inch (60 mm) fully-glazed trapway (the smooth internal waste channel) — a wide path that helps waste pass through without catching. It carries a single 1.6 GPF flush and the smooth one-piece body skips the crevices where dirt hides, with an EverClean finish that resists stain and odor-causing buildup.
The chair-height bowl sits at 16 1/2 inches, so it is a touch lower than the 17.3-inch ADA models but still eases sitting and standing for most adults. The soft-close seat takes a slow hinge so it never slams, and the fixture includes a chrome trip lever and bolt caps. The standout spec might be the warranty: 10 years, against the 1-year coverage almost everything else on this list offers.
The trade-off is weight and price. It tips the scale at 115 pounds — close to the heaviest here — and at the top of the pricing range, so it is the premium call in this roundup. For a household that has spent years fighting clogs with a plunger, that larger valve and trapway are exactly what they pay a premium for, backed by the longest warranty on the list.
Built to end the plunger: A 4-inch flush valve and 2 3/8-inch fully-glazed trapway push waste through with force single-flush toilets rarely match.
The premium you are paying for: At 115 pounds and 10-year warranty coverage, this is the heaviest, most long-term-protected fixture here.
Reach for this if: clogging has plagued your household and you want a large-valve one-piece with the longest warranty available in this roundup.
Look elsewhere if: you need a lighter install or want dual-flush water savings — this is a single 1.6 GPF model built for flush force.
Understanding the Specs
Rough-In Distance
Rough-in is the gap from the wall to the center of your floor drain, and it is the one measurement that can make a great toilet simply not fit. A 12-inch rough-in is the common standard in most homes, while a 10-inch model like the HOROW T0338W10 is made for tighter or older bathrooms. Measure from the finished wall to the center of the two flange bolts before you order, then match the number exactly — a 12-inch toilet pushed against a 10-inch drain leaves a visible gap, and a 10-inch unit on a 12-inch floor sits too far forward.
MaP Score and GPF
A MaP score rates how many grams of waste a toilet removes in one flush, with 1000 grams being the top mark many models reach and 800 grams still a solid everyday number. GPF stands for gallons per flush: a dual-flush toilet usually pairs a light 1.1 GPF setting for liquid waste with a heavier 1.6 GPF setting for solids. Lower GPF means a lower water bill, but the MaP score is what tells you whether it still clears the bowl in one pass.
FAQ
Willa 10-inch rough-in toilet fit where a 12-inch one cannot?
How do I measure my rough-in before buying a one-piece toilet?
What is a good MaP score for a one-piece toilet?
Is a chair-height toilet better than a standard-height one?
Do one-piece toilets use less water than two-piece models?
How heavy is a one-piece toilet to install?
What is the difference between a PP seat and a UF seat?
Can I replace the seat on a one-piece toilet later?
Do dual-flush toilets actually save water compared to a single 1.6 GPF flush?
How long should a one-piece toilet last?
Final Thoughts: The Verdict
If you want one dependable pick, the 1-piece toilet winner is the HOROW T0338W because it packs a 1000-gram dual flush and a 17.3-inch chair-height seat into a 26-inch-deep body that fits small bathrooms. If saving water and going green matters most, grab the Casta Diva CD-T005 with its WaterSense label. And for a family tired of reaching for the plunger, the American Standard Champion 4 is the one to reach for, thanks to its huge 4-inch flush valve and long warranty. Whichever you pick, measure your rough-in first and confirm the seat height suits the people who will actually use it — those two checks matter more than any styling choice on this list.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, KitchPrep earns from qualifying purchases. This does not affect which products we feature.
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