Independent research, no fluff

What Is a Rimless Toilet?

A rimless toilet removes the hollow, enclosed rim channel found inside a conventional bowl and replaces it with one or two open jets that sweep water across the entire inner surface on every flush. No hidden cavity means nowhere for limescale, mold or bacteria to hide and nowhere your cleaning brush cannot reach. This guide explains how the open-rim flush works, what it trades away, how the best rimless toilets compare by MaP score, GPF and glaze, and which certified models pair the hygiene benefit of an open rim with the flush power to back it up.

Why Trust Best Flushing Toilets

Flushing power and MaP flush-test scores
Water efficiency (GPF and EPA WaterSense)
Aggregated owner reviews
Clog resistance and trapway design
Brand reliability and warranty

Research updated June 2026.

Quick Answer

The TOTO Drake II with Tornado Flush is the best rimless toilet for most homes: its two open nozzles swirl water around the full bowl with no hidden rim channel to trap grime, and it posts a 1,000-gram MaP flush score at 1.28 GPF with CeFiONtect glaze, so the open rim delivers on both hygiene and flush power simultaneously.

A rimless toilet is defined by what it removes from the inside of the bowl. On a conventional toilet, water travels from the tank into a hollow channel that runs around the full circumference of the rim. That channel is sealed, invisible from above and pierced by small holes, the rim jets, that trickle water downward to rinse the walls. The channel collects scale, mold and bacteria where neither the flush nor a cleaning brush can reach, and clogged holes weaken the rinse over time. A rimless toilet removes the channel entirely and pushes water instead through one or two open nozzles, usually at the rear, that direct a fast swirl or sheet around the complete inner surface in a single pass. Every square centimeter of the bowl is now visible, rinsed on each flush and accessible to a brush or cloth.

The term appears on spec sheets as rimless, rim-free and open-rim. TOTO rarely uses the word, branding its open-jet system Tornado Flush, with two angled nozzles that spin water centrifugally. Older TOTO models use the Double Cyclone name for a similar two-jet approach. Kohler markets an open swirl as Revolution 360. Swiss Madison, Woodbridge, Horow and other value brands describe a 360-degree swirl without a proprietary name. The marketing language differs; the underlying principle is the same. To confirm a toilet is genuinely rimless, find a photo looking straight down into the bowl: open nozzles and a smooth, uninterrupted wall confirm it; a ring of small holes under a lip means it is a conventional rimmed design whatever the label says.

If you want the broadest ranking across all performance categories, start with the guide to the best flushing toilets, which covers rimless and rimmed models side by side. This article focuses on the rimless design specifically: what it changes, what it does not, and which models get the most from the open-rim concept when you pair it with a strong, documented flush.

What Exactly Is a Rimless Toilet and How Is It Different?

A rimless toilet has no enclosed rim channel around the inside of the bowl. A conventional toilet hides water in a sealed channel under the lip and feeds it through a ring of small holes that are impossible to scrub; a rimless toilet removes that channel and fires water from open nozzles at the back of the bowl that swirl the entire inner surface in one pass. The result is a bowl with no hidden cavity for grime, one that is fully rinsed on every flush and fully reachable when you clean. TOTO calls this Tornado Flush; Kohler calls it Revolution 360; other brands call it rim-free or open-rim.

The structural difference is smaller than the impact. A rimmed bowl has two water pathways from the tank: a large one to the rim channel and a smaller siphon-jet feed at the base. The rim channel does the bowl-wall rinse, but it divides the water among dozens of holes and the flow through each is gentle, uneven and partly blocked by scale as the toilet ages. When that channel is gone, all of the rinse water passes through one or two large open ports. The flow stays concentrated, moves faster and sweeps the bowl in a single rotation rather than a slow trickle through dozens of holes.

Recommended toilets in this guide

What rimless does not change is everything else about the toilet. It is not a separate flush mechanism: a rimless bowl can be gravity-fed, dual-flush or pressure-assisted, just like a rimmed one. It can be elongated or round, one-piece or two-piece, comfort height or standard height, and it connects to the same 12-inch rough-in with the same floor flange. Rimless is a single attribute layered on top of the rest. That means you still need to verify the rough-in, bowl shape, seat height and flush rating separately even after confirming the open-rim design. See our complete toilet buying guide for a full checklist of specs to match before you buy.

How Does a Rimless Flush Work Compared to a Normal Toilet?

A rimless flush works by releasing water from one or two open nozzles, normally at the rear of the bowl, that aim the flow in a swirling or sheeting pattern around the full inner wall in a single pass before draining through the trapway. Because there is no rim channel to split and slow the water, the open jets move faster and cover the bowl more evenly than rim holes can. TOTO's Tornado Flush uses two nozzles to create a centrifugal spin; Kohler's Revolution 360 swirls the whole bowl; cheaper open-rim designs use a single high-volume jet.

The difference in how the water moves is visible if you flush both types and watch. A rimmed toilet sends water trickling down through rows of small holes; the rinse creeps down the walls slowly and often misses patches. A rimless toilet sends a fast, visible sheet of water around the bowl from back to front, completing the circuit before much water has drained. That speed and evenness of coverage is the engineering advantage of the open-rim system, and it is why the stronger rimless designs, especially TOTO's Tornado Flush, can match the flush power of the best rimmed bowls while using the same or less water.

The MaP (Maximum Performance) score is the clearest independent measure of how well this translates into actual flush power. MaP tests how many grams of solid waste a toilet clears in a single flush, with 350 grams as the residential pass threshold and 1,000 grams as the published maximum. The TOTO Drake II with Tornado Flush reaches 1,000 grams at 1.28 gallons per flush. The TOTO UltraMax II also reaches 1,000 grams at 1.28 gallons. Both are EPA WaterSense certified. Those scores prove that eliminating the rim channel costs nothing in flush power when the nozzle geometry is engineered properly. The trap for buyers is assuming that all rimless bowls flush as well: a cheap open-rim design with poorly aimed jets can still flush weakly, which is why the MaP score remains the mandatory check even after confirming the open-rim structure.

Tip: verify open-rim design by looking into the bowl, not reading the label

Open the product listing and find a photo taken straight down into the bowl. A genuine rimless toilet shows a smooth, uninterrupted inner wall with one or two visible nozzles at the rear and no ring of small holes under the lip. A conventional bowl shows that ring of holes and a lip whose underside you cannot see. If the listing only shows the toilet from the outside, check the flush-system name: TOTO Tornado Flush, TOTO Double Cyclone and Kohler Revolution 360 confirm an open-rim design reliably, while a plain "rim-wash" or "rim-jet" description usually means a traditional enclosed rim.

Are Rimless Toilets More Hygienic and Easier to Clean?

Yes. Rimless toilets are more hygienic and easier to clean than conventional rimmed toilets because there is no hidden rim channel where bacteria, biofilm, mold and limescale accumulate beyond the reach of the flush or a cleaning brush. The worst staining on a traditional toilet almost always lives in the area just under the rim, inside the sealed channel, where neither water nor a brush ever fully penetrates. With no channel present, every surface is exposed, rinsed on each flush and reachable in a single pass with a brush. Owner reviews of Tornado Flush and similar open-jet models consistently cite reduced under-rim staining and faster cleaning as the most noticeable everyday benefit.

The hygiene case is the strongest argument for rimless and the easiest to confirm without any test. Look at the underside of the rim on any toilet that has been in service for a year or more and you will find the darkest, most persistent staining on the entire bowl, because that is where water trickles slowly through clogged holes, scale accumulates in the channel and the brush cannot reach. A rimless bowl has none of that. The inner wall is continuous and smooth, the nozzles are open and easy to inspect, and a short sweep with a brush covers the whole surface.

The benefit amplifies in hard-water homes. On a rimmed toilet, dissolved minerals in the water deposit inside the rim holes and the hidden channel over months and years, eventually blocking some holes, weakening the flush and making the scale impossible to reach with descaler. A rimless bowl avoids that entirely: the open nozzles are visible and accessible, so any scale that forms is easily removed, and the flush stays at its original strength. Pairing rimless with a slick glaze amplifies the benefit further. TOTO's CeFiONtect ion-barrier coating and American Standard's EverClean antimicrobial surface make the smooth, fully reachable bowl wall harder for scale and biofilm to grip in the first place. For hard-water households in particular, that combination of open rim plus antimicrobial glaze eliminates nearly every condition a stubborn stain needs to take hold.

Top recommendations

Three rimless and open-rim toilets that clean easily and flush hard

These three models represent what a well-executed rimless design delivers: an open bowl with no hidden channel to scrub, paired with a flush strong enough to clear the bowl every time. Each has a documented MaP score and EPA WaterSense certification, so easy cleaning is not the trade-off for performance.

Best overall

TOTO Drake II

Best for most homes 4.8

TOTO's Tornado Flush delivers a two-nozzle open swirl that fully rinses the bowl on every flush, and the CeFiONtect ion-barrier glaze makes the smooth, exposed surface nearly stain-proof. At 1,000-gram MaP and 1.28 GPF, this is the clearest proof that an open rim costs nothing in flush strength.

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Best one-piece

TOTO UltraMax II

Best seamless design 4.7

A seamless one-piece body with Tornado Flush and CeFiONtect glaze gives you no tank-to-bowl seam, no rim channel and no rough external surfaces to scrub, making the easy-clean concept complete inside and out. WaterSense certified at 1.28 GPF with a 1,000-gram MaP score.

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Best value

Swiss Madison St. Tropez

Best for modern baths 4.4

An affordable rimless one-piece with a 360-degree open swirl, a skirted glazed exterior and dual-flush at 1.1 and 1.6 gallons, delivering the full cleaning benefit of the open rim at a price point that makes the design accessible to budget-conscious buyers.

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Expert Take

The most common mistake when shopping for a rimless toilet is treating the open-rim label as a guarantee of flush power. It is not: rimless describes how water is distributed inside the bowl, not how forcefully it is expelled. A poorly designed cheap open-rim bowl can still flush weakly and still splash. The right order of checks is: confirm the open-rim design by looking into the bowl, then confirm the flush by checking the published MaP grams (800 minimum, 1,000 for heavy use), then verify the model in the EPA WaterSense database. TOTO's Tornado Flush models pass all three checks together, which is why they dominate this category despite being priced above budget alternatives.

Toilet	Best For	MaP Score	GPF	Flush System	Rating	Check Price
TOTO Drake II	Best overall rimless	1,000 g	1.28	Tornado Flush	4.8	Check price
TOTO UltraMax II	Best one-piece rimless	1,000 g	1.28	Tornado Flush	4.7	Check price
TOTO Aquia IV	Best dual-flush rimless	900 g	0.8 / 1.28	Tornado Flush	4.6	Check price
Swiss Madison St. Tropez	Best value rimless	800 g	1.1 / 1.6	360-degree swirl	4.4	Check price
Woodbridge T-0001	Best budget one-piece	800 g	1.28	Open swirl	4.3	Check price
Kohler Cimarron (Rev 360)	Best Kohler open-swirl	1,000 g	1.28	Revolution 360	4.6	Check price
Conventional rimmed bowl	Lowest upfront cost	600-1,000 g	1.28-1.6	Rim-hole rinse	4.2	Check price

Rimless vs Rimmed Toilet: Which Should You Choose?

A rimless toilet is better for cleaning and hygiene because it has no hidden rim channel where bacteria, mold and limescale accumulate out of reach of the brush or the flush. A rimmed toilet is more widely available at the budget end and is slightly cheaper in equivalent models. On flush power the two are equal when both are well designed: the best rimless and rimmed bowls each reach a 1,000-gram MaP score. For most buyers the open rim is the better long-term choice; the rimmed bowl wins only where budget and selection are the primary constraints.

The comparison is more useful framed as a question of what each design trades away rather than which is better in every dimension. A rimless toilet trades the enclosed rim, and with it the dirtiest hiding place for grime, and in its most important downgrade it occasionally costs slightly more at equivalent build quality. A rimmed toilet trades the easy-clean open bowl but offers more models, especially at lower prices, and the familiar design that plumbers and installers work with daily. The flush differences, where they exist at all, depend entirely on how well each particular bowl is engineered, not on whether the rim is open or enclosed.

Choose a rimless toilet if: hygiene and easy cleaning are priorities, you live in a hard-water area where scale blocks rim holes over time, your bathroom sees heavy use, or you are installing a toilet you expect to keep for a decade or longer and want it to clean as well at year ten as at year one. Also choose rimless if you are pairing a bidet seat, since the smooth open bowl is easier to keep hygienic alongside a seat-mounted wash nozzle. For the full decision framework that covers bowl shape, seat height and flush type alongside the rimless question, see our guide on how to choose a toilet.

Choose a rimmed toilet if: your budget is tight and you need the widest selection of models below a specific spend, or you are replacing a toilet in a rental or secondary bathroom where long-term maintenance is a lower priority, or a specific style or rough-in you need only comes in a rimmed design. The rimmed bowl is not a wrong choice; it is simply the design that has a hidden surface to scrub, and the one whose flush can weaken over years as scale builds in the rim holes.

Which Rimless Toilet Has the Best Flush Power?

The TOTO Drake II and the Kohler Cimarron with Revolution 360 flushing both reach the 1,000-gram MaP ceiling, the published maximum for independent flush testing, at 1.28 gallons per flush. Both are EPA WaterSense certified. The TOTO Drake II is the stronger overall recommendation because it combines the 1,000-gram flush with CeFiONtect glaze, a two-nozzle Tornado Flush swirl, and a consistent owner-review track record. The TOTO Aquia IV reaches 900 grams at an ultra-low 0.8 gallons on the full flush and is the best pick where water savings are the primary goal.

MaP testing is the most reliable published data for comparing flush power between models. The test uses a standardized soybean-paste media at various weights to simulate real waste and records the maximum weight cleared in a single flush. A score of 350 grams passes the residential minimum; 500 to 800 grams covers everyday household use with a margin; 1,000 grams is the maximum published score and comfortably handles the heaviest residential demand. The TOTO Drake II with Tornado Flush reaches 1,000 grams at 1.28 GPF, the same ceiling as the best rimmed gravity toilets, and it does so with an open-rim bowl that fully rinses the walls simultaneously.

The TOTO Aquia IV deserves a separate mention because it stretches the rimless concept into ultra-efficient territory: its dual-flush posts 900 grams at 0.8 gallons on the full flush and is WaterSense certified, making it one of the most efficient powerful-flushing toilets on the market. For a large household that wants to cut water consumption without sacrificing flush reliability, the Aquia IV's open-rim Tornado Flush is an unusually good combination. Gerber's Viper and Avalanche models are strong rimmed alternatives that reach high MaP scores, but they use conventional rim-hole rinses, so they lack the cleaning advantage of the open-jet designs.

Are Rimless Toilets Good for Preventing Clogs?

Rimless toilets are not inherently better at preventing clogs than rimmed ones, because clog resistance depends on trapway diameter, flush power and glaze, not on the rim design. A rimless bowl with a wide, fully glazed trapway and a high MaP score is as clog-resistant as the best rimmed models. The TOTO Drake II with its 2.125-inch glazed trapway and 1,000-gram MaP score is one of the most clog-resistant toilets available, rimless or rimmed, but the advantage comes from those specs, not from the open rim.

Clog resistance has three real drivers. First is trapway diameter: a wider, fully glazed channel passes waste with less friction. The TOTO Drake II uses a 2.125-inch trapway and coats it with CeFiONtect, which reduces adhesion at the walls. American Standard's Champion 4 uses a fully glazed 2.375-inch trapway, the widest commonly available, and reaches 1,000 grams with a conventional rimmed bowl, which demonstrates that trapway and flush power matter more than rim design for clog resistance. Second is MaP score: a higher score means more mass is cleared in a single flush with less risk of partial passage. Third is glaze quality on the trapway interior: unglazed ceramic grips waste; smooth glazed surfaces let it pass. None of these three factors are changed by removing or keeping the rim channel.

Where the rimless design does indirectly help with clogs is in hard-water homes. On a rimmed toilet, scale that builds in the rim holes reduces the flow of rinse water, which reduces the bowl water level and can make the flush less effective over time, increasing the risk of partial clears and eventual clogs. An open-rim bowl avoids that degradation: the jets stay clear, the flush delivers full power on flush number ten thousand exactly as on flush number one, and the bowl water level stays consistent. So in a hard-water house, a rimless toilet is indirectly more clog-resistant in the long term because its flush does not weaken the way a scale-blocked rimmed toilet does.

Buying advice

How to Choose the Right Rimless Toilet: Five Specs That Matter

The rimless label gets you an easy-clean open bowl, but five measurable specs separate a model that fits your bathroom and flushes reliably from one that disappoints. Check each one before you buy.

1. Confirm a true open-rim design by looking into the bowl

Not every toilet labeled rimless is genuinely rim-free, and some brands use the term loosely to describe a shallower rim rather than an absent one. Find a photo taken straight down into the bowl in the manufacturer listing. A true open-rim toilet shows a smooth, continuous inner wall with one or two open nozzles at the rear and no ring of small holes under the lip. The flush-system name is a reliable shortcut: TOTO Tornado Flush, TOTO Double Cyclone and Kohler Revolution 360 each confirm an open-rim rinse. A listing that only shows the exterior and describes a plain rim wash or rim jet is almost certainly a conventional enclosed rim.

2. Check the MaP score before trusting any flush claim

Because rimless describes the bowl rinse and not the flush mechanism, flush power is a separate question requiring a separate check. MaP scores are published at map-testing.com and in manufacturer data sheets for most major models. Use 800 grams as the floor for a household of two to four people, 1,000 grams for large families, frequent clogs or heavy use. The TOTO Drake II (1,000 g at 1.28 GPF) and TOTO Aquia IV (900 g at 0.8 GPF) set the standard. Any rimless model that does not publish a MaP score should be treated with suspicion, because the open rim alone does not guarantee strong clearing power.

3. Verify the EPA WaterSense listing by model number

WaterSense certification means the toilet uses 1.28 gallons per flush or less and passed a third-party performance test. Confirm the exact model number in the EPA database at epa.gov/watersense rather than relying on the box label alone, because not every variant in a product family carries the same certification. Most leading rimless models, including the TOTO Drake II, UltraMax II and Aquia IV, are WaterSense certified. Dual-flush rimless options like the Aquia IV and the Swiss Madison St. Tropez drop the light flush below 1.1 gallons, so you gain both the easy-clean bowl and meaningful water savings. For a full breakdown of efficiency options, see our guide to the best water saving toilets.

4. Match rough-in, bowl shape, height and body style

Rimless is one attribute: confirm the rest independently. Rough-in is the distance from the finished wall to the center of the floor-drain bolts, usually 12 inches in most US homes but sometimes 10 or 14 inches in older construction; always measure before ordering. Elongated bowls are more comfortable for most adults; round bowls save up to two inches of depth, which matters in a small bathroom. Comfort-height bowls at 16 to 18 inches from floor to seat rim make sitting and standing easier for tall adults and those with joint issues. One-piece bodies like the TOTO UltraMax II have no tank-to-bowl seam and pair naturally with the easy-clean theme of an open rim; two-piece models like the Drake II are lighter and usually cheaper to ship. See our comparisons of round vs elongated toilets and one piece vs two piece toilets for the full trade-off analysis.

5. Prioritize a documented glaze to extend the cleaning benefit

The open rim removes the worst hiding place for grime, but the rest of the bowl wall still benefits from a slick surface. TOTO's CeFiONtect is an ion-barrier glaze applied at the molecular level that reduces the electrical attraction between the ceramic and the charged particles in hard-water scale and biofilm. American Standard's EverClean is an antimicrobial coating that inhibits bacteria, mold and mildew from taking hold. Both make the smooth, fully reachable rimless bowl wall substantially harder to stain and much faster to clean. When two rimless models are otherwise close in MaP score and GPF, the one with a documented antimicrobial or ion-barrier glaze will deliver more of the easy-clean promise over a five-year or ten-year ownership period.

Expert Take

Five checks cover almost every rimless toilet purchase correctly: look into the bowl to confirm the open-rim design, check the MaP grams separately (800 minimum, 1,000 for heavy use), verify the exact model number in the EPA WaterSense database, measure your rough-in before ordering, and choose a glazed surface to extend the cleaning advantage long-term. Stick to TOTO, Kohler, Swiss Madison and Woodbridge for the rimless open-rim class; the no-name imports where splashing complaints cluster most often are where those five checks reveal problems. A rimless toilet from a reputable brand that passes all five checks will stay cleaner, flush reliably and need less maintenance than a conventional rimmed bowl across a decade of normal use.