Which Is Better, a One-Piece or a Two-Piece Toilet?
Neither is better outright — a one-piece toilet wins on cleaning and appearance, and a two-piece wins on handling and range. In a one-piece the tank and bowl are fused into a single seamless unit, so there is no visible connection between them and no bolted seam to work a cloth around. A two-piece keeps them separate and joins them during installation, which is why it is lighter to carry and why you can replace one part without touching the other.
Everything else follows from that. One-piece models are often used in modern bathroom designs, while two-piece models cover a wider variety of configurations and price points. For the full comparison, read our one piece vs two piece toilet guide or look at the two-piece toilets we carry.
What the elongated bowl adds
Elongated means the bowl is oval and measures about 18.5 inches from the seat bolts to the front rim, against about 16.5 inches for a round bowl. Those two inches buy more seating support and cost you two inches of floor space. Building guidance generally calls for around 21 inches of clear space in front of the bowl, so measure from the flange to the wall, vanity or door swing before you commit. In a powder room or a tight alcove, a round bowl toilet is the sensible call.
The bowl shape also settles your bidet seat. Elongated and round seats are not interchangeable, and round is the less widely made of the two, so an elongated bowl leaves you far more to choose from if you plan to add an elongated bidet seat later.
What is in this collection
Every toilet here is TOTO. That covers the classic ceramic one-piece lines — UltraMax, UltraMax II, Nexus, Aquia IV, Carlyle II, Aimes, Legato, Aurora, Redington, Supreme II and Carolina II — and the integrated smart toilets that share the elongated shape, including the WASHLET G5A, the G5A Lite and the NEOREST range. The G5A Lite is a one-piece skirted design running TORNADO FLUSH at 1.2 or 1.0 GPF at Universal Height; the NEOREST NX1, NX2, RS, AS and LS are dual flush at 1.0 and 0.8 GPF. Three models in the list — the NEOREST WX1, the NEOREST WX2 and the RP with WASHLET RW — are wall-hung rather than floor-mounted, so they mount on an in-wall carrier and have no floor rough-in at all.
Two technologies come up repeatedly across these listings. TORNADO FLUSH uses two powerful nozzles that create a centrifugal, cyclonic rinsing action which reduces waste buildup and keeps the bowl cleaner. CEFIONTECT is TOTO's extraordinarily smooth glaze, which prevents particulates from adhering to porous ceramic surfaces.
How to Choose the Right One-Piece Elongated Toilet
Choosing the right one-piece elongated toilet comes down to four checks, in order: rough-in, seat height, flush volume, and whether the WASHLET comes with it. Get the first one wrong and nothing else matters, because the toilet will not sit on your drain.
1. Measure your rough-in before anything else
Rough-in is the distance from the finished wall to the center of the closet bolts at the base of the toilet. Three sizes exist — 10, 12 and 14 inches — and 12 inches is the standard. Measure to the finished wall rather than the baseboard, and use the back pair of bolts if your toilet has four. If the number lands within half an inch of 10, 12 or 14, that is your rough-in. Our toilet rough-in size guide covers the odd readings.
This narrows the field more than most buyers expect. Among the TOTO lines here, Aquia IV, Aimes, Legato, Aurora, Carlyle II, Carolina II and Redington reach 10 and 14 inch through TOTO's Unifit adapter, ordered with the toilet. Nexus offers 12 and 14 inch only — there is no 10-inch Nexus. UltraMax, UltraMax II and Supreme II are 12 inch only. If your bathroom measures 10 inch, start with the 10 inch rough-in models.
2. Choose a seat height
TOTO builds most one-piece lines in two heights. Standard Height puts the seat about 15 inches from the floor; Universal Height puts it about 17 to 19 inches and meets the ADA seat height. TOTO encodes it in the model number, where an F in the SKU means Universal Height — MW7763346CEFG is the taller version of MW7763346CEG. Check the SKU; the two often sit side by side on a listing. Anyone who finds a low seat awkward to stand up from tends to prefer Universal Height toilets.
3. Decide on flush volume
GPF is gallons per flush. Federal law caps it at 1.6 gallons, and WaterSense certification requires 1.28 or less. Several states, California, Texas, Colorado and Georgia among them, have adopted 1.28 as the legal maximum for new installations, so check your local requirement first. A 1.6 model does not flush better than a modern 1.28 — TOTO's TORNADO FLUSH, DYNAMAX TORNADO FLUSH and G-Max systems were engineered around the lower volume, and performance varies between series, not between volumes within one.
4. Skirted or classic, and the WASHLET question
A skirted one-piece has a smooth ceramic panel covering the trapway, leaving nothing to wipe around at the base. Nexus is one of TOTO's most popular skirted ranges, and TOTO's skirted one-piece ranges are largely the same ones that use the Unifit adapter, so styling and rough-in are one decision. Several models here are listed twice: once as the bare bowl, once as a WASHLET+ set with the seat already matched to it.
Why One-Piece Toilets Are Harder to Install
One-piece toilets are harder to install because the tank and bowl arrive fused as a single unit, so the whole fixture has to be lifted and set on the flange in one movement. A two-piece is carried in parts and assembled in place, which is what makes it easier to handle. The plumbing is no different — same flange, same closet bolts, same supply connection — so this is an argument for a second pair of hands.
Two things are worth planning around. A Unifit adapter goes on during installation and cannot be added later without lifting the toilet, and the part numbers differ by series — a Carlyle II adapter will not fit an Aquia IV. And if you are buying an integrated smart toilet or a WASHLET+ set, confirm there is a grounded outlet within reach before the fixture goes down.