The best one-piece toilets
No tank bolts, no gap between tank and bowl, nothing to clean around. One of these is not quite what it seems.
By Sawyer V. · · How we research
The short answer
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Quick picks
Tap any row for the full write-up. Prices are checked against Amazon rather than remembered — where we have no verified figure the button says so.
| # | Product | Best for | Renter | Price |
|---|---|---|---|---|
| 1 | No photo yet Santa Rosa One-Piece Compact Elongated Toilet, 1.28 gpf Compact elongated, Comfort Height and 1.28 gpf, with the largest published water surface of the three, in the footprint of a round bowl. | Most bathrooms with a 12 in. rough-in | Owner-only | |
| 2 |  Adair One-Piece Elongated Toilet, 1.28 gpf A full elongated bowl with an 11 by 7-3/4 in. water surface, Comfort Height, and a Cachet Quiet-Close seat that unlatches for cleaning. | Larger bathrooms and taller adults | Owner-only | |
| 3 |  Memoirs Stately One-Piece Compact Elongated Toilet with Skirted Trapway, 1.28 gpf A skirted one-piece — no trapway curves on the outside — with a ReadyLock install that avoids drilling the floor. | Smooth sides that wipe clean in one pass | Owner-only | |
| — |  Veil One-Piece Compact Elongated Smart Toilet, Dual-Flush One-piece in name, a smart toilet in practice: tankless, pump-assisted, and it needs a dedicated GFCI circuit and 6 gpm of supply. | Skip this one | Owner-only | No buy link |
What one-piece actually buys you
A two-piece toilet is a tank bolted onto a bowl, with a gasket between them. A one-piece is a single casting. Kohler’s description is that one-piece toilets “integrate the tank and bowl into a seamless, easy-to-clean design”.
In daily life, that means no gap between tank and bowl for dust and splashes to collect in, and no tank bolts to corrode or tank gasket to replace years down the line. It is a cleaning and longevity argument, not a flushing one. The full comparison is here.
Compact elongated is the quiet win
Two of our three picks are compact elongated. That shape exists to solve the usual dilemma between comfort and floor space, and it is the reason the Santa Rosa is our first pick rather than the full-elongated Adair. Round against elongated is covered in detail here.
The numbers worth comparing
- Rough-in: 12 in. on all three conventional picks. The Memoirs Stately has 10 in. and 14 in. kits.
- Rim height: 16-1/2 in. from floor to rim on all three drawings, before the seat. All three are Comfort Height.
- Water surface: Santa Rosa 11 x 8-1/8 in.; Adair 11 x 7-3/4 in.; Memoirs Stately 9-5/8 x 7-3/8 in.
- Rim to water: Santa Rosa 6-1/4 in.; Adair 6-1/16 in.; Memoirs Stately 5-3/8 in.
- Depth from the wall: Santa Rosa and Memoirs Stately 27-3/4 in.; Adair 28-9/16 in.
None of the three publishes a MaP score, the independent flush test many buyers look for. That is a gap in Kohler’s sheets, not a sign of weakness, but it means we cannot rank them on flush performance and we will not pretend to.
Check the rough-in before anything else
Rough-in is the distance from the finished wall to the center of the drain, and it is fixed by the floor. Measure it before you fall for a toilet. If yours is 10 in., the three Kohler models here need the Memoirs Stately’s kit or a different toilet, and the 10 in. rough-in toilets are on the small-bathroom page.
Height
All three are what Kohler calls Comfort Height, its term for chair-height seating that “makes sitting down and standing up easier for most adults”. Whether that is right for everyone in your house is a real question, particularly with children. Comfort height against standard height is covered here.
Before install day
A one-piece arrives as a single casting rather than two parts, so plan on two people to carry it in and set it. Kohler does not publish shipping weights on these sheets.
Every toilet here rates Owner-only on our install rating. Replacing a toilet means a new wax ring on the drain and a new supply connection. If you rent, the part you can change is the seat.
Every pick in full
3 we would buy, and one we would not. Each carries its Renter-Safe Install Rating, the published specs behind it, and the honest gap in what we know.
1. Best overall
Santa Rosa One-Piece Compact Elongated Toilet, 1.28 gpf
Kohler · K-3810 · best for most bathrooms with a 12 in. rough-in
Compact elongated, Comfort Height and 1.28 gpf, with the largest published water surface of the three, in the footprint of a round bowl.
The Kohler Santa Rosa gets the one thing most people want from a new toilet — the comfort of an elongated bowl — without the thing that usually comes with it. Kohler’s compact elongated bowl “offers added comfort while occupying the same space as a round-front bowl”, and the drawing puts the whole toilet at 27-3/4 in. deep.
The bowl numbers are good: an 11 by 8-1/8 in. water surface and 6-1/4 in. from rim to water. The trapway is a 2-1/8 in. fully glazed passage, and the flush is 1.28 gpf through Kohler’s AquaPiston canister, which Kohler says “requires less force to actuate than a 3″ (76 mm) flapper”.
A Quiet-Close seat with Quick-Release is part of the toilet. The supply line is sold separately.
Renter-Safe Install Rating
- Drilling
- None
- Tools
- Not published
- Time to fit
- Not published
- Power
- None
- Reversible on move-out
- No
Why: Replacing a toilet means removing the old one, seating a new wax ring on the flange and reconnecting the supply. It is work on the property's drainage and never a tenant's change.
Read from published documentation, not from fitting one. Kohler — Santa Rosa K-3810 specification sheet. How the verdict is derived: renter-safe ratings explained.
What’s wrong with it
A left-hand trip lever only, and the supply line is not included.
What we can’t tell you
Kohler's sheet publishes no MaP flush-performance score, and it sends you to the website for the warranty terms.
Published specifications
| Type | One-piece, floor-mount |
|---|---|
| Bowl | Compact elongated — “occupying the same space as a round-front bowl” |
| Height | Comfort Height; 16-1/2 in. from floor to rim on Kohler's drawing |
| Flush | 1.28 gpf (4.8 lpf), AquaPiston canister |
| Trapway | 2-1/8 in. fully glazed |
| Water surface | 11 in. x 8-1/8 in.; rim to water surface 6-1/4 in. |
| Rough-in | 12 in. |
| Footprint | 27-3/4 in. deep, 18-3/4 in. wide, 28-3/16 in. tall |
| Seat | Quiet-Close elongated seat with Quick-Release |
| Standards | EPA WaterSense; ADA when installed to its requirements |
| Warranty | KOHLER Toilets and Seats Limited Warranty — terms are on Kohler's website, not the sheet |
| MaP rating | Not published on the specification sheet |
#ad We have no verified live price for this one right now, so we are not showing a number. How we’re funded.
2. Best full elongated
Adair One-Piece Elongated Toilet, 1.28 gpf
Kohler · K-3946 · best for larger bathrooms and taller adults
A full elongated bowl with an 11 by 7-3/4 in. water surface, Comfort Height, and a Cachet Quiet-Close seat that unlatches for cleaning.
The Kohler Adair is the choice when the room has space to give. Its full elongated bowl “offers added room and comfort”, and it projects 28-9/16 in. from the wall on Kohler’s drawing — 13/16 in. more than the Santa Rosa.
The water surface is 11 by 7-3/4 in., with 6-1/16 in. from rim to water, on the same 2-1/8 in. glazed trapway and 1.28 gpf AquaPiston flush. It carries WaterSense and California Energy Commission listings.
The seat is a Cachet Quiet-Close that Kohler says “quickly unlatches from the toilet for easy removal and convenient cleaning”. That is a bigger deal than it sounds: the hinge area is the part of a toilet nobody cleans properly, because nobody can reach it.
Renter-Safe Install Rating
- Drilling
- None
- Tools
- Not published
- Time to fit
- Not published
- Power
- None
- Reversible on move-out
- No
Why: A full toilet replacement on the property's drainage: out with the old one, new wax ring, new supply connection. An owner's job.
Read from published documentation, not from fitting one. Kohler — Adair K-3946 specification sheet. How the verdict is derived: renter-safe ratings explained.
What’s wrong with it
At 28-9/16 in. deep it is the longest of the conventional toilets here.
What we can’t tell you
No MaP score on the sheet, and the warranty terms are on Kohler's website, not the sheet.
Published specifications
| Type | One-piece, floor-mount |
|---|---|
| Bowl | Elongated — “offers added room and comfort” |
| Height | Comfort Height; 16-1/2 in. from floor to rim on Kohler's drawing |
| Flush | 1.28 gpf (4.8 lpf), AquaPiston canister |
| Trapway | 2-1/8 in. fully glazed |
| Water surface | 11 in. x 7-3/4 in.; rim to water surface 6-1/16 in. |
| Rough-in | 12 in. |
| Footprint | 28-9/16 in. deep, 16-5/16 in. wide at the tank, 28-7/16 in. tall |
| Seat | Cachet Quiet-Close seat that “quickly unlatches from the toilet for easy removal” |
| Standards | EPA WaterSense; California Energy Commission; ADA when installed to its requirements |
| Warranty | KOHLER Toilets and Seats Limited Warranty — terms are on Kohler's website, not the sheet |
| MaP rating | Not published on the specification sheet |
#ad Price $759.26 as of October 18, 2026. Prices change; Amazon’s listing is the one that counts. How we’re funded.
3. Best skirted
Memoirs Stately One-Piece Compact Elongated Toilet with Skirted Trapway, 1.28 gpf
Kohler · K-6428 · best for smooth sides that wipe clean in one pass
A skirted one-piece — no trapway curves on the outside — with a ReadyLock install that avoids drilling the floor.
The Kohler Memoirs Stately takes the one-piece argument a step further. Its “Skirted trapway simplifies cleaning”: the sides of the base are smooth and flat instead of following the curves of the trapway, so the worst part of cleaning a toilet simply is not there.
Skirted toilets can be awkward to fit, which is what Kohler’s ReadyLock system is for. Kohler says it “eliminates the need to drill into the floor for standard 12″ (305 mm) rough-in”, and it offers 10 in. and 14 in. rough-in kits for other drains.
It is compact elongated, Comfort Height and 1.28 gpf, and 27-3/4 in. deep on the drawing.
Renter-Safe Install Rating
- Drilling
- None
- Tools
- Not published
- Time to fit
- Not published
- Power
- None
- Reversible on move-out
- No
Why: Kohler's ReadyLock system removes the floor drilling, but it is still a toilet replacement on the property's drainage.
Read from published documentation, not from fitting one. Kohler — Memoirs Stately K-6428 specification sheet. How the verdict is derived: renter-safe ratings explained.
What’s wrong with it
The smallest water surface here at 9-5/8 by 7-3/8 in., with 5-3/8 in. from rim to water, which leaves more of the bowl above the waterline.
What we can’t tell you
No MaP score on the sheet, and the warranty terms live on Kohler's website.
Published specifications
| Type | One-piece, floor-mount, “Skirted trapway simplifies cleaning” |
|---|---|
| Bowl | Compact elongated |
| Height | Comfort Height; 16-1/2 in. from floor to rim on Kohler's drawing |
| Flush | 1.28 gpf (4.8 lpf), AquaPiston canister |
| Trapway | 2-1/8 in. |
| Water surface | 9-5/8 in. x 7-3/8 in.; rim to water surface 5-3/8 in. |
| Rough-in | 12 in. standard; 10 in. and 14 in. rough-in kits “also available” (K-5383, K-5381) |
| Installation system | ReadyLock, which “eliminates the need to drill into the floor for standard 12" (305 mm) rough-in” |
| Footprint | 27-3/4 in. deep, 18-1/4 in. wide, 28-1/4 in. tall |
| Seat | Quiet-Close compact elongated seat with Quick-Release |
| Standards | EPA WaterSense; California Energy Commission; ADA when installed to its requirements |
| Warranty | KOHLER Toilets and Seats Limited Warranty — terms are on Kohler's website, not the sheet |
| MaP rating | Not published on the specification sheet |
#ad We have no verified live price for this one right now, so we are not showing a number. How we’re funded.
The one to skip
Veil One-Piece Compact Elongated Smart Toilet, Dual-Flush
Kohler · K-5401-PA · best for only if you want a smart toilet anyway
One-piece in name, a smart toilet in practice: tankless, pump-assisted, and it needs a dedicated GFCI circuit and 6 gpm of supply.
The Kohler Veil is, technically, a one-piece toilet — Kohler’s own title is “One-piece compact elongated smart toilet, dual-flush”. It turns up in one-piece searches for exactly that reason.
But it is a different purchase. It is tankless, with a direct water supply and pump-assisted flushing, and the sheet asks for two things an ordinary toilet does not: a minimum supply flow of 6 gpm, and “One dedicated circuit required, protected with Class A Ground-Fault Circuit-Interrupter (GFCI)” at 120 V and 15 A.
If what you want from a one-piece is an easy-clean toilet with a tidy profile, those requirements are a lot to take on. If what you actually want is the bidet, that is a different question, and it is answered here.
Renter-Safe Install Rating
- Drilling
- None
- Tools
- Not published
- Time to fit
- Not published
- Power
- Dedicated GFCI circuit (120 V, 15 A)
- Reversible on move-out
- No
Why: A toilet replacement plus a dedicated, GFCI-protected circuit beside the toilet, which most bathrooms do not have. Plumber and electrician.
Read from published documentation, not from fitting one. Kohler — Veil K-5401-PA specification sheet. How the verdict is derived: renter-safe ratings explained.
What’s wrong with it
A dedicated GFCI circuit and a 6 gpm supply requirement that an ordinary toilet does not ask for.
What we can’t tell you
No MaP score published, and a three-year warranty covering a lot of electronics.
Published specifications
| Type | One-piece smart toilet “with integrated personal cleansing”; tankless, direct water supply |
|---|---|
| Flush | “Dual flush offers a choice of 0.8 or 1.28 gpf”; pump-assisted |
| Supply requirement | Minimum flow rate 6 gpm (22.7 lpm) |
| Cleansing | Stainless steel wand with adjustable spray shape, position, pressure, temperature, pulsate and oscillate; front and rear warm-water wash |
| Self-cleaning | UV light and electrolyzed water clean the wand surfaces |
| Comfort | Heated seat and warm-air dryer, both adjustable; automatic deodorization; bowl nightlight |
| Lid | Motion-activated, hands-free opening and closing |
| Power outage | “Emergency flush supports up to 100 flushes during power outage” |
| Electrical | “One dedicated circuit required, protected with Class A Ground-Fault Circuit-Interrupter (GFCI)” — 120 V, 15 A |
| Rough-in | 12 in. |
| Footprint | 26-1/8 in. deep, 17-1/4 in. wide on Kohler's drawing |
| Water surface | 7-15/16 in. x 5-5/8 in.; trapway 1-15/16 in. |
| Warranty | “KOHLER Intelligent Toilet and C3 Cleansing Seat Three-Year Limited Warranty” |
There is no buy button on this one. It is easy enough to find if you want it anyway — we would rather point you at something that is still on the wall in a year.
Where to buy
Everything recommended on this page, in one place. Each link is an Amazon Associates link — we earn a commission at no extra cost to you, and it never decides a pick.
- Check price on Amazon
Santa Rosa One-Piece Compact Elongated Toilet, 1.28 gpf
Kohler · K-3810 · Renter verdict: Owner-only
- $759.26View on Amazon
Adair One-Piece Elongated Toilet, 1.28 gpf
Kohler · K-3946 · Renter verdict: Owner-only
- Check price on Amazon
Memoirs Stately One-Piece Compact Elongated Toilet with Skirted Trapway, 1.28 gpf
Kohler · K-6428 · Renter verdict: Owner-only
#ad Prices are not shown because we only publish figures we have verified on the day. How we’re funded.
Questions people actually ask
are one piece toilets better
For cleaning, yes: there is no gap between tank and bowl and no tank bolts or gasket. They are not better at flushing because they are one piece — the flush comes from the valve and trapway design.
do one piece toilets come with a seat
The three Kohler one-piece toilets here all list a Quiet-Close seat as part of the toilet. The supply line is sold separately on each.
what is a compact elongated toilet
An elongated bowl shaped to fit a round-front footprint. Kohler says its compact elongated bowl offers added comfort 'while occupying the same space as a round-front bowl'.
what rough in do one piece toilets need
The Kohler one-piece toilets here are 12 inch rough-in. The Memoirs Stately also offers 10 and 14 inch rough-in kits. Measure from the finished wall to the center of the drain before you buy.
Sources
Read next
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