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Quick answer from a licensed plumber: Buy the Kohler Corbelle K-3814 for most bathrooms. It flushes 1.28 gallons, MaP lists it at 1,000 g, and Kohler’s ReadyLock system mounts the skirt without drilling the floor on a 12 in. rough-in. For a dual flush, the TOTO Aquia IV. For the least water with the seat included, the American Standard Aspirations at 0.80 gallons. Before you buy any skirted toilet, check where your shutoff valve comes out of the wall, because the skirt has to clear it.
Our pick for most bathrooms: the Kohler Corbelle K-3814, with a 1,000 g MaP score on 1.28 gallons and ReadyLock skirt mounting. Check the Kohler Corbelle K-3814 on Amazon
A skirted toilet has smooth china sides that hide the trapway, so there are no trapway curves along the base to scrub around. This page covers only skirted (concealed trapway) toilets and the install details the skirt changes: rough-in, where the shutoff sits behind the skirt, and the mounting hardware. Our best toilet guide ranks toilets of every style on flush power. This one is for buyers who already want a skirted bowl. Every pick below flushes 1.28 gallons or less, is listed as meeting EPA WaterSense on its maker’s sheet, and has a MaP score.
Skirted Toilets Compared
| Toilet | Flush | MaP (Sept 24 list) | Seat | How the skirt mounts | Supply spot on the maker’s drawing |
|---|---|---|---|---|---|
| Kohler Corbelle K-3814 | 1.28 gpf | 1,000 g | Sold separately | ReadyLock: trapway piece on the flange, no floor drilling at 12 in. | 6 in. up, 8 in. left of center |
| TOTO Aquia IV CST446CEMFGN | 1.28 / 0.9 gpf dual | 800 g, Premium | Sold separately | Unifit piece plus two floor mounting blocks, side screws | 4-3/4 in. up, 5-7/8 in. left of flange center |
| American Standard Aspirations 251AA809 | 0.80 gpf | 1,000 g, Premium | Included | T-bolts with retainers, knobs and covers | 5-1/2 in. up, 2-1/4 or 8 in. left of center |
| American Standard Cadet Touchless 2989709 | 1.28 gpf, touchless | 1,000 g | Included | T-bolts with retainers and knobs | 5-1/2 in. up, 2-1/4 or 8 in. left of center |
From the Kohler, TOTO and American Standard documents and the MaP list linked below, read on September 30, 2026. MaP scores are grams of test waste removed in one flush. Every linked listing was sold by Amazon.com and in stock that day.
How to Choose a Skirted Toilet
Measure the rough-in first
Rough-in is the distance from the finished wall to the center of the flange bolts. All four picks are built for 12 in. American Standard’s sheets say the combination is designed to rough-in at a minimum of 12 in. from the finished wall. TOTO adds that mounting the flange at a nominal 12 in. keeps the right gap between the tank and the wall. For a 10 in. or 14 in. rough-in, Kohler sells skirted trap kits (K-5383 for 10 in., K-5381 for 14 in.) and TOTO sells Unifit adapters (TSU48.10 and TSU48.14). We did not find a 10 in. or 14 in. option on the American Standard sheets. Measuring steps are in how to measure toilet rough-in.
Check where the shutoff comes out of the wall
This is the detail that trips up skirted installs. On a standard toilet the supply line drops down beside an open trapway. On a skirted bowl the china runs close to the floor, so the stop valve and supply line have to clear the skirt. Each maker draws a different spot. Kohler draws the Corbelle’s 3/8 in. NPT supply 6 in. up and 8 in. left of center. TOTO recommends 4-3/4 in. up and 5-7/8 in. left of the flange center, and says the angle stop must stick out less than 3 in. from the wall. American Standard suggests 5-1/2 in. up, at either 2-1/4 in. or 8 in. left of center, and marks those spots as suggested. Plumber’s note: before you buy, measure your stop from the floor and from the flange center and compare it with the sheet. A stop a few inches off can usually be handled with a different angle stop or supply line. One far off means moving the stub-out, and that means opening the wall. Stop types by pipe are in supply stop valves by pipe type.
Hook up the supply line in the right order
American Standard says that on a skirted bowl, connect the water supply line before you mount the tank. TOTO says the same: the hose goes on the fill valve before the tank goes on the bowl. Kohler’s guide lists a 7/8 in. supply hose and says not to use a cone supply. American Standard says to hand-tighten the supply nut, use no sealant on it, and replace the supply line if it still leaks. Supply line sizing is in toilet supply line size, and our picks are in best toilet supply lines.
Know the mounting hardware
A skirt hides the usual bolt spots, so each maker solves the hold-down its own way. Kohler’s ReadyLock bolts a trapway piece to the floor flange, and Kohler says it needs no floor drilling at a 12 in. rough-in. TOTO’s Unifit piece sits on the flange, two mounting blocks screw to the floor, and side screws hold the bowl. TOTO lists a drill bit for concrete or tile floors. American Standard ships T-bolts with retainers and bowl-to-floor knobs. Its Aspirations instructions say to secure a concealed-trap bowl with the supplied triangular nuts and snap the covers in place. TOTO and American Standard list the wax ring as not included, and Kohler lists a wax ring and hardware kit as a recommended accessory. Plumber’s note: lay out the hardware before you pull the old toilet, and set a new wax ring every time. More in how to replace a toilet wax ring.
Flush volume and MaP
All four picks flush 1.28 gallons or less. Our best toilet guide covers the states that cap toilets at 1.28 gallons. For flush power, use the MaP list. It shows the Corbelle, Aspirations and Cadet Touchless at 1,000 g and the Aquia IV at 800 g. MaP Premium is a separate tier. MaP says Premium models need a score of at least 600 g and an effective flush volume no more than 1.1 gallons, with dual flush full flushes capped at 1.28 gallons. The Aquia IV and Aspirations are Premium. Dual flush trade-offs are in single flush vs dual flush.
Seat height
All four are the taller chair-height style. Kohler draws the Corbelle at 16-1/2 in. to the rim, and American Standard lists 16-1/2 in. for the Aspirations. TOTO calls the Aquia IV Universal Height. If you want a lower bowl, see comfort height vs standard toilets.
Kohler Corbelle K-3814 Skirted Two-Piece Toilet
1.28 gpf, EPA WaterSense · Revolution 360 rim + AquaPiston canister · 2-1/8 in. glazed trapway · MaP 1,000 g · 12 in. rough-in (10 in. and 14 in. kits sold separately) · Comfort Height, 16-1/2 in. to the rim on Kohler’s drawing · ReadyLock skirt mounting · seat and supply line sold separately · lifetime limited warranty on the china, 10 years on mechanical parts (Kohler toilet warranty, home use)
Kohler’s sheet calls the Corbelle a “two-piece elongated toilet with skirted trapway” and says the skirted trapway “simplifies cleaning.” The reason it is the top pick is the mounting. Kohler says its ReadyLock system is “a simple solution for skirted toilets” that “eliminates the need to drill into the floor” on a standard 12 in. rough-in. Kohler’s skirted-trapway installation guide (1302029-2) shows how: a trapway piece bolts to the floor flange with tee bolts, brackets mount to it, and the bowl sets over it and fastens through the sides of the skirt, with caps pressed over the holes. The flush is a Revolution 360 rim with Kohler’s AquaPiston canister in the tank, and MaP lists the K-3814 at 1,000 g on 1.28 gallons.
Kohler’s drawing puts the 3/8 in. NPT supply 6 in. above the floor and 8 in. left of the toilet’s centerline, and lists 15 to 80 psi static pressure. Kohler sells separate 10 in. (K-5383) and 14 in. (K-5381) “Full Skirt Trap and Attachment” systems for other rough-ins. The seat and supply line are not in the box. Kohler’s spec sheet puts the Corbelle under its Toilets and Seats Limited Warranty, which covers the vitreous china for life and mechanical parts for ten years in a home, for toilets made after January 1, 2020. The older 1302029-2 install guide still prints a one-year warranty; the warranty sheet is the current document. The linked listing is the K-3814-RA, which has the trip lever on the right; Kohler’s base K-3814 sheet shows a left-hand lever. If this listing is short, the Kohler Cimarron K-5310 uses the same ReadyLock mounting and AquaPiston canister and is also 1,000 g on MaP; Kohler’s Cimarron sheet lists AquaPiston only, not the Revolution 360 rim. For a seat 2-1/2 in. higher than Comfort Height, Kohler makes the Corbelle Tall K-33814, which adds Kohler’s ContinuousClean dispenser. We did not find a MaP score for the K-33814 on the September 24 list.
- ReadyLock mounting with no floor drilling at a 12 in. rough-in, per Kohler
- MaP 1,000 g on 1.28 gallons
- Kohler sells 10 in. and 14 in. skirted rough-in kits
- CleanCoat surface treatment against water scale, per Kohler
- Seat and supply line sold separately
- Kohler’s parts, not a universal flapper, when the canister seal wears
- Linked listing is the right-hand lever version
- Not MaP Premium: a single 1.28-gallon flush is over Premium’s 1.1-gallon effective flush cap
Verdict: The skirted toilet to buy for most bathrooms: full flush power on 1.28 gallons and a mounting system built for the skirt.
TOTO Aquia IV CST446CEMFGN Skirted Dual Flush Toilet
Dual flush 1.28 / 0.9 gpf, EPA WaterSense · Dynamax Tornado Flush · 2-1/4 in. trap diameter · MaP 800 g, MaP Premium · 12 in. rough-in (10 in. and 14 in. Unifit adapters sold separately) · Universal Height · completely skirted · push button on the lid · seat sold separately · one-year limited warranty
TOTO’s sheet says the Aquia IV has a “completely skirted design for a sleek and understated look that’s easier to clean.” It is dual flush: TOTO lists 1.28 gallons for a full flush and 0.9 gallons for a half flush, picked with a chrome push button on the tank lid. TOTO’s CEFIONTECT glaze is meant to keep waste from sticking to the china. MaP lists it at 800 g and rates it MaP Premium. MaP’s Premium criteria cap a dual flush model’s full flush at 1.28 gallons and require a score of at least 600 g.
TOTO’s manual is the most specific of the four on skirted plumbing. It recommends a shutoff 4-3/4 in. above the floor and 5-7/8 in. left of the floor flange’s center. It recommends an angle stop with the outlet facing up, in or down, says the stop must stick out less than 3 in. from the wall, and does not recommend a straight stop or a front-facing outlet. The bowl mounts on TOTO’s Unifit rough-in piece with two mounting blocks screwed to the floor, then side screws with caps. TOTO says to connect the supply hose to the fill valve before the tank goes on the bowl, and it asks for a hose bent no tighter than a 50 mm radius. Optional TSU48.10 and TSU48.14 Unifit adapters cover 10 in. and 14 in. rough-ins.
- Half flush of 0.9 gallons for liquids
- MaP Premium rated, per MaP
- TOTO publishes exact shutoff valve location for the skirt
- 10 in. and 14 in. Unifit adapters, per TOTO
- MaP 800 g, below the 1,000 g picks here
- Seat sold separately
- Mounting blocks are screwed to the floor
- One-year limited warranty, original buyer only
Verdict: The pick if you want a half flush and the smoothest-sided bowl, and you can put the shutoff where TOTO asks.
American Standard Aspirations EcoStrength 251AA809 Skirted Toilet
0.80 gpf ultra-high efficiency, vacuum assisted · 2-1/8 in. trapway · MaP 1,000 g, MaP Premium · 12 in. minimum rough-in · chair height, 16-1/2 in. rim · smooth-sided concealed trapway · elongated seat included (slow-close, per the listing) · lifetime chinaware, 10-year mechanical, 1-year seat warranty
American Standard calls this a “chair height elongated bowl with smooth-sided, concealed trapway,” and the Amazon listing says the skirted sides “eliminate the hard-to-reach crevices where dirt and grime can collect.” It is the low-water pick: 0.80 gallons per flush, which American Standard credits to its EcoStrength vacuum assisted technology. MaP lists the 251AA809 at 1,000 g and MaP Premium. The seat comes in the box. American Standard’s warranty matches Kohler’s on the china and mechanical parts, lifetime and 10 years, and adds 1 year on the included seat.
American Standard’s drawing gives two suggested supply spots, both 5-1/2 in. above the floor: 2-1/4 in. left of center or 8 in. left of center. The same drawing shows the skirt 11-3/16 in. wide at the floor, so the 2-1/4 in. spot sits behind the skirt (our reading of the drawing). The instructions say that on a skirted bowl you connect the water supply line before you mount the tank. They also say to hand-tighten the supply nut with no plumber’s putty, pipe dope or other sealant, which American Standard says voids the warranty. Normal supply pressure must be at least 20 psi, and the toilet may need 1 to 5 flushes to prime after install. The linked 251AA809 has the lever on the left; American Standard lists the 251AA808 for a right-hand lever.
- 0.80 gallons per flush with a MaP 1,000 g score
- Seat included
- Lifetime chinaware and 10-year mechanical warranty, per American Standard
- Two suggested supply positions on the drawing
- Needs at least 20 psi, per the instructions
- May take 1 to 5 flushes to prime after install
- 12 in. rough-in only on the sheet
- Supply line sold separately
Verdict: The skirted toilet for the lowest water bill without giving up a top MaP score, with the seat in the box.
American Standard Cadet Touchless 2989709 Concealed Trapway Toilet
1.28 gpf, EPA WaterSense · touchless sensor flush with manual override · 3 in. flush valve · 2-1/8 in. trapway · MaP 1,000 g · 12 in. rough-in · chair height elongated bowl · smooth-sided concealed trapway · slow-close seat included · batteries included (3 AAA sensor, 4 AA control module)
This is the skirted toilet for a hands-free flush. American Standard says a hand held within 1-1/2 in. of the sensor face for about two seconds triggers the flush. The 2-1/2 in. sensor can mount on the wall within 3 feet of the toilet or on top of the tank. The sheet lists the bowl as a “siphon action jetted bowl with smooth-sided, concealed trapway” with a 3 in. flush valve, 1.28 gallons per flush and a 1,000 g MaP score. The seat comes with it.
Plan on batteries: 3 AAA in the sensor and 4 AA in the control module in the tank, all included. The instructions say the sensor flashes slowly 12 times when the tank module needs batteries and quickly 5 times when the sensor does. A push button on the left side of the tank flushes it by hand if the batteries die. The supply spots on the drawing are the same as the Aspirations: 5-1/2 in. up, 2-1/4 in. or 8 in. left of center. The concealed-trap install note says to connect the supply hose to the supply valve during setup, and the bolt caps are not used on concealed-trap bowls. Warranty: lifetime on chinaware, 5 years on mechanical parts and 1 year on electronic parts and the seat.
- Touchless flush with a manual button backup
- MaP 1,000 g at 1.28 gallons
- Seat and batteries included
- Sensor mounts on the wall or the tank lid
- Batteries to change in two places
- Electronics carry a one-year warranty
- 12 in. rough-in only on the sheet
- Supply line and wax ring sold separately
Verdict: The pick for a hands-free flush on a smooth-sided bowl, if you are fine changing batteries.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
Cleaning a Skirted Toilet
The skirt is the reason to buy one: smooth sides with no trapway curves to scrub. Clean it the way the makers say. TOTO says to use a detergent or non-abrasive toilet cleaner and a soft plastic brush. For hard water stains, TOTO says to use vinegar or a lime-dissolving cleaner and a non-scratch pad made for porcelain. American Standard says to wash with mild, soapy water, rinse with clear water and dry with a soft cloth. All three makers warn against in-tank cleaners. Kohler says products with chlorine (calcium hypochlorite) can seriously damage tank fittings, and that in-tank cleaners void its warranty. TOTO and American Standard give the same warning. Plumber’s note: the skirt leaves the floor joint as the one seam to keep clean. A bead of caulk around the base keeps mop water out from under the bowl, and American Standard’s instructions mention caulking the base when the floor is not level.
Before You Buy
- Measure the rough-in. 12 in. fits all four picks. For 10 in. or 14 in., look at Kohler’s skirted kits or TOTO’s Unifit adapters.
- Measure the stop valve. Note its height above the floor and its distance left of the flange center, then compare it with the maker’s drawing in the table.
- Check the stop valve itself. TOTO recommends an angle stop with the outlet up, in or down, and says it must sit less than 3 in. off the wall. A stop that will not close fully should be replaced before the new toilet goes in.
- Count the parts you still need. The Kohler and TOTO toilets need a seat. All four need a supply line and a wax ring.
- Check your pressure. Kohler lists 15 to 80 psi static, TOTO 8 psi flowing minimum, and the Aspirations at least 20 psi.
Installing a Skirted Toilet
The steps follow a standard toilet swap: shut off the water, flush and sponge out the bowl, pull the old toilet, scrape the flange and plug it with a rag so sewer gas does not escape. Kohler and American Standard both give that rag or cover warning. The skirt changes three things. First, the hold-down hardware goes on the flange or floor before the bowl, per each maker’s guide. Second, the supply line has to be connected before the tank goes on, per American Standard and TOTO. Third, you cannot see the wax seal from the side once the bowl is down, so set the bowl straight down and do not rock it. American Standard says not to move the bowl after placement, or the seal may break. TOTO says to check for rocking and shim it if needed. Our toilet replacement guide covers the full job.
Plumber’s note: if the flange sits below the finished floor, fix that before setting any toilet; see toilet flange too low. Back-to-back toilets on one stack need the fitting the makers name: Kohler says a 45° double wye and not a double sanitary tee, and TOTO and American Standard also call for a wye-type fitting rather than a double sanitary tee or cross. If the closet bend, the flange or the stop valve needs work, that is a job for a licensed plumber, and many towns require a permit for it.
FAQ
What is a skirted toilet?
A skirted toilet has smooth china sides that hide the trapway, the S-shaped channel on the side of a standard bowl. Makers also call it a concealed trapway. Kohler says the skirted trapway simplifies cleaning, and TOTO says its completely skirted design is easier to clean. The flush works the same way; the difference is the outside of the bowl and how it mounts to the floor.
Are skirted toilets harder to install?
They mount differently. The skirt covers the usual bolt spots, so each maker uses its own hardware: Kohler’s ReadyLock bolts a trapway piece to the flange, TOTO screws mounting blocks to the floor, and American Standard uses T-bolts with knobs and covers. Both American Standard and TOTO say to hook up the supply line before the tank goes on. Read the maker’s guide before you pull the old toilet.
Can I get a skirted toilet for a 10-inch or 14-inch rough-in?
Some. Kohler sells 10 in. and 14 in. Full Skirt Trap and Attachment systems (K-5383 and K-5381) for its skirted toilets, and TOTO sells 10 in. and 14 in. Unifit adapters (TSU48.10 and TSU48.14) for the Aquia IV. The American Standard sheets here list a 12 in. rough-in only. Measure from the finished wall to the center of the flange bolts first; our rough-in guide shows how.
Where should the shutoff valve be for a skirted toilet?
Follow the toilet’s sheet. TOTO recommends an angle stop 4-3/4 in. above the floor, 5-7/8 in. left of the flange center, sticking out less than 3 in. American Standard suggests 5-1/2 in. above the floor at 2-1/4 in. or 8 in. left of center. Kohler draws the Corbelle supply 6 in. up and 8 in. left of center. If your stop is far from that spot, the skirt can hit it.
Is a skirted toilet the same as a one-piece toilet?
No. One-piece means the tank and bowl are one casting. Skirted describes the sides of the bowl. All four picks here are two-piece toilets with skirted bowls. See one-piece vs two-piece toilets for that choice.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber. Every spec here comes from the maker documents and the MaP list linked below, or from the Amazon listings we link; nothing comes from hands-on testing. On September 30, 2026, every linked listing was sold by Amazon.com and in stock. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- Kohler: Corbelle K-3814 specification sheet (6-8-2024), K-3814-RA (right-hand lever) sheet
- Kohler: Cimarron K-5310 specification sheet (6-20-2024), Corbelle Tall K-33814 specification sheet
- Kohler: installation guide 1302029-2-B (skirted trapway attachment; listed on Kohler’s K-3814 product page), KOHLER Toilets and Seats Limited Warranty (1420362-12)
- TOTO: Aquia IV CST446CEMFGN spec sheet SS-02061, Installation and Owner’s Manual 0GU179 (CST446), product page
- American Standard: Aspirations EcoStrength 251AA809 spec sheet (6/25), installation instructions 7302538-100
- American Standard: Concealed Trapway Cadet Touchless 2989.709 spec sheet, installation instructions 7302484-100
- MaP Toilet Testing: tank-type toilet list dated September 24, 2026, MaP PREMIUM criteria
- Amazon listings for the Kohler K-3814-RA, K-5310 and K-33814, TOTO CST446CEMFGN, American Standard 251AA809 and 2989709 (linked above)
Bottom Line
A skirted toilet trades a little install planning for a bowl that wipes clean. The Kohler Corbelle K-3814 is the one to buy for most bathrooms, and the Cimarron K-5310 is a close Kohler alternative. The TOTO Aquia IV adds a half flush, the American Standard Aspirations uses 0.80 gallons with the seat included, and the Cadet Touchless flushes with a wave. Measure the rough-in and the stop valve against the maker’s drawing, and connect the supply line before the tank goes on.