The TOTO Aquia IV is the toilet for buyers who want serious water savings without dropping to a no-name brand. It pairs a dual-flush button with TOTO's Tornado Flush, a rim-jet system that swirls water around the bowl instead of dumping it through holes, and it does it in a low-profile, fully skirted body. This review breaks down its dual-flush GPF figures, MaP flush-test score, WaterSense certification, CeFiONtect glaze, install quirks and the recurring themes across thousands of aggregated owner reviews, so you can decide whether the Aquia IV fits your bathroom.
The TOTO Aquia IV is the dual-flush toilet to buy if you want real water savings backed by a premium brand. Its 0.8 and 1.28 gallon dual-flush buttons average around 0.9 gallons per flush, it carries EPA WaterSense certification, and the Tornado Flush rinses the bowl cleanly without rim holes. The trade-off is a softer 800 gram flush than a 1000 gram brute like the Drake.
Research updated June 2026.
TOTO is the most respected name in residential toilets, a Japanese manufacturer that effectively wrote the modern playbook for low-flow flushing performance. The Aquia line is where TOTO puts its dual-flush technology, and the Aquia IV is the current generation of that family. Where TOTO's single-flush Drake chases the highest possible MaP score on a fixed 1.28 or 1.6 gallons, the Aquia IV takes a different angle entirely: give the user a choice between a tiny 0.8 gallon liquid flush and a stronger 1.28 gallon solid flush, then average that down to roughly 0.9 gallons over a typical day. The result is one of the most water-efficient mainstream toilets you can buy from a premium brand, wrapped in a sleek skirted body that looks far more expensive than it is.
Before getting into the details, it helps to anchor on the one number that lets you compare any toilet on equal footing. MaP, short for Maximum Performance, is an independent flush test that measures how many grams of solid waste a toilet clears in a single flush. A score of 600 grams is workable, 800 grams is strong, and 1000 grams is the practical ceiling for a residential gravity toilet. The Aquia IV's full 1.28 gallon flush posts an 800 gram MaP score, which is strong rather than maximum, and that gap between it and a 1000 gram Drake is the central trade-off this review unpacks. The Aquia IV appears in our pillar guide to the best flushing toilets precisely because it balances that flush power against class-leading water use, and this review walks through whether that balance holds up against the published specs and the aggregated owner record.
This review is not based on lab testing in our own bathroom, and we will not pretend it is. We build it from published TOTO specifications, independent MaP flush-test data, EPA WaterSense certification status, and the consistent themes that surface across thousands of verified owner reviews. We weigh flush power against water use, then factor in trapway width, rinse coverage, ease of cleaning, install difficulty and how the design holds up after years of daily service. Where the Aquia IV has a genuine weakness, we say so plainly.
The headline numbers that define how the Aquia IV performs, drawn from TOTO's published specs and independent MaP testing.
| Toilet | Best For | MaP | GPF | Rating | Check Price |
|---|---|---|---|---|---|
| TOTO Aquia IV | Water-saving dual flush | 800 g | 0.8 / 1.28 GPF | 4.5 | Check price |
| TOTO Drake | Maximum single-flush power | 1000 g | 1.28 GPF | 4.7 | Check price |
| Kohler Cimarron Dual Flush | Brand-name dual flush | 800 g | 1.0 / 1.28 GPF | 4.4 | Check price |
| American Standard Champion 4 | Clog resistance | 1000 g | 1.6 GPF | 4.5 | Check price |
| Woodbridge T-0019 | Smart-look one piece | 800 g | 1.0 / 1.6 GPF | 4.4 | Check price |
The dual-flush mechanism is the whole point of the Aquia IV, so it is the right place to start. Two buttons sit on top of the tank lid. The smaller one triggers a 0.8 gallon partial flush meant for liquid waste, and the larger one triggers a 1.28 gallon full flush for solids. The idea is simple and effective: most toilet uses do not need a full 1.28 gallons, so giving the user a lighter option for the majority of flushes saves a meaningful amount of water over a year. TOTO rates the effective average around 0.9 gallons per flush, and that figure is what makes the Aquia IV one of the lowest real-world water users in any mainstream lineup. For comparison, a single-flush 1.28 gallon toilet uses the full amount every time, and a legacy 1.6 gallon model uses double the Aquia IV's partial flush.
Aggregated owner reviews back up the efficiency claim, with a recurring theme of noticeably lower water bills after switching from an older 1.6 gallon or 3.5 gallon toilet. The dual-flush buttons are top-mounted and intuitive, and the wide flush valve inside the tank moves water quickly enough that even the 0.8 gallon partial flush clears liquid and light paper without hesitation. This is the reason the Aquia IV anchors our guide to the best dual-flush toilets and shows up in nearly every water-saving roundup we publish.
Quick tip. The single biggest factor in how much water a dual-flush toilet actually saves is user habit. The Aquia IV only hits its 0.9 gallon average if the household reaches for the small 0.8 gallon button on liquid flushes. If everyone always presses the full-flush button out of habit, you are effectively running a 1.28 gallon single-flush toilet and leaving the savings on the table.
The second pillar of the Aquia IV is the flush system itself. Most toilets distribute rinse water through a ring of small holes under the bowl rim. Those holes are a known weak point: they clog with mineral scale over time, they leave dry streaks where coverage is uneven, and they are awkward to clean. TOTO's Tornado Flush replaces that ring with two powerful angled nozzles that fire water tangentially into the bowl, creating a centrifugal swirling action that wraps water around the entire inner surface. The practical benefit is more complete bowl coverage per gallon, which is exactly what a low-water toilet needs, because you have less water to work with and you want every drop scrubbing the bowl rather than dropping straight down the center.
In aggregated reviews, the most consistent praise for the Aquia IV is bowl cleanliness, and Tornado Flush is the reason. Owners regularly report fewer skid marks and less frequent scrubbing compared with their previous toilet, and because there is no ring of rim holes, the under-rim area does not accumulate the grime and scale that builds up on hole-rimmed designs. TOTO pairs Tornado Flush with its CeFiONtect glaze, an ultra-smooth ceramic coating that fills the microscopic pits in the china so waste and bacteria have less to cling to. The combination is why the Aquia IV earns a place in our guide to the best self-cleaning toilets, even though no toilet is truly self-cleaning.
Flush power is the Aquia IV's most important trade-off, and it is worth being direct about it. The full 1.28 gallon flush earns an 800 gram MaP score. On the MaP scale, 800 grams is a strong, dependable result that clears the waste a normal household produces in a single flush, and it is the same score posted by many well-regarded toilets. What it is not is the 1000 gram maximum that single-flush specialists like the TOTO Drake and its flush power and specs achieve on the same 1.28 gallons. The reason is physics: a dual-flush valve and the gentler swirling action of Tornado Flush prioritize clean rinse coverage and water savings over the raw siphonic punch of a wide-open single-flush valve. You trade a slice of brute clearing power for efficiency and bowl cleanliness.
For the vast majority of households, that trade is invisible in daily use. Aggregated owner reviews rarely flag the Aquia IV as a weak flusher, and double-flushing complaints are uncommon when owners use the full button for solids as intended. The honest exception is heavy-use scenarios: a home with frequent very large loads, a household that uses a lot of thick paper, or an older drain line with a marginal slope may occasionally need a second flush. Buyers in those situations who want maximum single-flush clearing are better served by a 1000 gram model, and we point them to our guide to the strongest flushing toilets. For everyone else, 800 grams paired with class-leading water savings is the smarter balance.
Worth knowing. A common mistake is judging a dual-flush toilet by its 0.8 gallon partial flush and assuming it is weak. The partial flush is designed only for liquid and light paper. The number that matters for clearing solids is the full-flush MaP score, which for the Aquia IV is a strong 800 grams. Use the full button for solids and the toilet performs as rated.
The Aquia IV leans modern and minimalist, and its design is one of its quieter strengths. It is a two-piece toilet with a low-profile tank that sits lower than a typical model, giving it a sleek, contemporary silhouette that reads as more expensive than it is. The standout styling feature is the fully skirted trapway: instead of the exposed, contoured trapway bumps you see on the side of a conventional toilet, the Aquia IV's outer surface is a smooth, flat skirt that hides the plumbing channel entirely. That smooth skirt has two benefits, one visual and one practical. It looks clean and modern, and there are no nooks or contours to trap dust, so wiping it down is a single uninterrupted pass. That is why the Aquia IV features in our guides to the best skirted toilets and the best compact toilets.
On comfort, the Aquia IV is sold in TOTO's Universal Height, which places the bowl rim at roughly 17 inches with the seat, comparable to a standard chair and compliant with ADA requirements. That comfort height is easier on the knees than a low standard-height bowl and a better fit for seniors and taller adults, which is why it appears in our guide to the best comfort-height toilets. The bowl is elongated for everyday comfort. TOTO typically sells the Aquia IV as a bowl-and-tank combination, and the SoftClose seat is available, sometimes bundled and sometimes purchased separately depending on the SKU, so confirm what is included on the exact listing.
The skirted design that makes the Aquia IV so easy to clean introduces one install consideration worth flagging up front. Because the trapway is enclosed by the smooth skirt, the toilet does not mount over the floor flange in the conventional way. Older Aquia models used a separate bolt-down base plate that some installers found fiddly. The Aquia IV refined this with a more straightforward skirted mounting, but it still differs from a standard exposed-trapway toilet. The toilet uses a standard 12 inch rough-in, which fits the vast majority of North American bathrooms, but the skirted mounting means it is worth reading the install instructions before you start rather than assuming it bolts down exactly like your old toilet.
The second design reality is the low-profile tank. The lower tank height that gives the Aquia IV its modern look also means it has less vertical drop, and TOTO compensates with a wide, efficient flush valve to keep the flush effective. In practice this works well, but it is part of why the Aquia IV is engineered for an 800 gram strong flush rather than a 1000 gram maximum. Buyers who specifically want a tall, traditional tank with the most aggressive possible siphon should look at a single-flush Drake instead. Buyers who want the clean modern look and the water savings will find the low tank a feature rather than a flaw.
Installing the Aquia IV follows the general process of any floor-mounted toilet: set the wax ring or supplied gasket, position the bowl and skirted base over the closet bolts, level it, attach the tank, and connect the supply line. The skirted design means the mounting hardware differs slightly from a conventional toilet, so the TOTO instructions are worth following step by step rather than improvising. As a two-piece, the tank and bowl are separate during transport, which keeps each piece lighter to handle than a heavy one-piece. Aggregated owner reviews occasionally mention the skirted mounting taking a little extra attention, but rarely describe the install as genuinely difficult on a standard 12 inch rough-in.
On long-term value, the Aquia IV makes a strong case built on water savings, bowl cleanliness and TOTO's brand reliability. TOTO is widely regarded as the most dependable mass-market toilet brand, parts are readily available, and the Aquia IV is backed by TOTO's limited warranty. The everyday value is in the utility bill: a household that uses the 0.8 gallon partial flush habitually can cut water use substantially versus a single-flush or legacy toilet, and that saving compounds year after year. Add in the reduced scrubbing from Tornado Flush and CeFiONtect, and the Aquia IV earns its keep through lower running cost and less maintenance rather than the lowest sticker. Check the current price on Amazon to see how it stacks up against the alternatives below.
The Aquia IV is the toilet we recommend first to buyers who lead with water efficiency and want a premium brand behind it. The dual-flush 0.9 gallon average and the genuinely clean Tornado Flush rinse are real advantages that most owners notice every day. But be honest with yourself about flush power: the 800 gram MaP score is strong, not maximum, so if your household routinely produces heavy loads or your plumbing is marginal, step up to a 1000 gram single-flush Drake instead. For a normal home that values savings and a clean bowl, the Aquia IV is one of the smartest picks TOTO makes.
The Aquia IV is not the cheapest dual-flush toilet on the market, and buyers focused purely on upfront cost can find lower-priced dual-flush options from brands like Swiss Madison or Woodbridge. The Aquia IV's value argument is different: you are paying for TOTO's reliability, the Tornado Flush rinse, the CeFiONtect glaze and the genuinely low 0.9 gallon average, then recovering that premium over years of lower water bills and less scrubbing. For a household that flushes thousands of times a year, the difference between a 0.9 gallon average and a 1.28 or 1.6 gallon toilet adds up, and the Aquia IV pairs that saving with the dependability TOTO is known for. It fits naturally alongside the efficient performers in our WaterSense toilets guide.
The Aquia IV is the dual-flush toilet to buy when water efficiency and a clean bowl matter most. Its 0.8 and 1.28 gallon buttons average around 0.9 gallons per flush, the Tornado Flush rim jets rinse the entire bowl without rim holes, CeFiONtect glaze slows buildup, and the fully skirted body wipes clean in a single pass, all backed by TOTO's reputation for reliability.
The trade-offs are real and worth weighing. The 800 gram MaP score is strong but below the 1000 gram maximum of single-flush specialists, the skirted mounting takes a little more attention to install, and it costs more than budget dual-flush rivals. For a normal household that values savings and cleanliness, those concessions are easy to accept.
Think of the Aquia IV as the efficiency-and-cleanliness pick, not the brute-force pick. It is the toilet we recommend when someone wants to cut their water bill and stop scrubbing skid marks, and the Tornado Flush genuinely delivers on the second part. But if the buyer describes a clog problem or a household of heavy users, point them to a 1000 gram Drake or Champion 4 instead and let the Aquia IV win the homes where savings matter more than maximum power.
The Aquia IV is the right call for buyers whose top priority is cutting water use without dropping to a no-name brand: eco-minded households, homes in regions with strict water rules, and anyone tired of scrubbing a hole-rimmed bowl. It suits standard 12 inch rough-in bathrooms, rewards households that will actually use the small flush button, and its skirted body, comfort height and CeFiONtect glaze add everyday convenience on top of the savings. If water efficiency and bowl cleanliness are the numbers you would circle on a spec sheet, the Aquia IV is one of the most direct answers available.
You should look elsewhere if maximum single-flush clearing power is your top concern, if your household produces very heavy loads or your drain line is marginal, or if you want the lowest possible purchase price. In those cases a 1000 gram single-flush model or a budget dual-flush toilet makes more sense, and a few rivals are worth a look.
The Aquia IV is the premium water-saving specialist, but depending on whether you prioritize raw flush power, a one-piece look or a lower price, one of these three may suit you better.
A single-flush workhorse with the G-Max siphon and a maximum 1000 gram MaP score on 1.28 gallons, the choice when you want TOTO reliability with the strongest possible single-flush clearing rather than dual-flush savings.
Check price on Amazon
A seamless one-piece dual-flush toilet with a modern skirted body and soft-close seat included, a value alternative for buyers who want the smart, high-end look without the TOTO price.
Check price on Amazon
A comfort-height two-piece offered in a dual-flush form with Kohler's AquaPiston canister flush, a refined brand-name alternative if you prefer Kohler styling and dealer support over TOTO.
Check price on AmazonIf you want to weigh the Aquia IV against those options in detail, a few of our other reviews are worth reading. The maximum-power single-flush benchmark is covered in our TOTO Drake review and its flush power and specs, the clog-resistance specialist is broken down in our American Standard Champion 4 review, the brand-name cross-shop is detailed in our Kohler Cimarron review with its flush power and specs, and buyers drawn to a seamless modern body should read our Woodbridge T-0019 review of that smart-look one piece.
When buyers ask us to settle the Aquia IV against the field, the honest framing is this: the TOTO Drake and Champion 4 beat it on raw flush power with their 1000 gram scores, and budget rivals beat it on price. The Aquia IV wins on the axis most households actually live with day to day, the combination of genuine water savings and a clean bowl on every flush. Choose it when efficiency and cleanliness are the failures you are buying against, not maximum clearing volume.
Yes, especially if water efficiency and a clean bowl are your priorities. Its dual-flush buttons average around 0.9 gallons per flush, it posts a strong 800 gram MaP score on the full flush, Tornado Flush rinses the entire bowl without rim holes, and it earns a consistently strong aggregated owner rating around 4.5 out of 5. Its main trade-off is a softer flush than a 1000 gram single-flush brute.
The Aquia IV uses 0.8 gallons on the partial flush for liquid waste and 1.28 gallons on the full flush for solids, which averages roughly 0.9 gallons per flush in typical use. That is well below a standard 1.28 gallon single-flush toilet and far below a legacy 1.6 gallon model. It carries EPA WaterSense certification.
The Aquia IV's full 1.28 gallon flush posts an 800 gram MaP score. On the MaP scale, where 600 grams is workable and 1000 grams is the maximum for a residential gravity toilet, 800 grams is a strong result that clears normal household waste in a single flush, though it is below the maximum 1000 grams of toilets like the TOTO Drake.
Tornado Flush is TOTO's rim-jet flushing system that sends water into the bowl through two angled nozzles instead of a ring of small rim holes. The jets create a centrifugal swirl that washes the entire bowl surface, improving rinse coverage and reducing the streaking and scale buildup that affect hole-rimmed toilets. It is one of the cleaner-rinsing flush designs available.
Yes. The TOTO Aquia IV carries EPA WaterSense certification, which requires a toilet to use no more than 1.28 gallons per flush while still meeting flushing performance standards. Because the Aquia IV averages around 0.9 gallons thanks to its dual-flush design, it comfortably qualifies and is a strong pick in regions with strict water rules.
No, not in normal use. Its 800 gram MaP full flush and TOTO's efficient flush valve clear typical household waste reliably, and aggregated owner reviews rarely report clogging when the full button is used for solids. Very heavy loads or marginal drain lines may occasionally need a second flush, which is the trade-off for its low water use versus a 1000 gram single-flush model.
Yes, the Aquia IV is sold in TOTO's Universal Height, which places the bowl rim at roughly 17 inches with the seat, comparable to a standard chair and ADA compliant. That comfort height is easier on the knees than a low standard-height bowl and a better fit for seniors and taller adults. The bowl is elongated for everyday comfort.
It depends on the SKU. TOTO offers the Aquia IV with a SoftClose seat in some configurations and as a bowl-and-tank combination requiring a separate seat in others. Confirm on the specific listing whether a seat is included, and if not, budget for a compatible elongated SoftClose seat to match the bowl.
The Aquia IV uses a standard 12 inch rough-in, the distance from the finished wall to the center of the floor drain, which fits the vast majority of North American bathrooms. Because the trapway is skirted, the mounting hardware differs slightly from a conventional toilet, so read the TOTO install instructions and confirm clearances before ordering.
It installs like a standard floor-mounted toilet, but the fully skirted trapway means the mounting hardware differs from an exposed-trapway model, so following the TOTO instructions step by step matters more than usual. Aggregated owner reviews occasionally mention the skirted mounting taking extra attention, but rarely describe the install as genuinely difficult on a standard 12 inch rough-in.
CeFiONtect is TOTO's ultra-smooth ceramic glaze that fills the microscopic pits in the bowl's china surface, giving waste, bacteria and mineral scale far less to cling to. It is not self-cleaning and you will still scrub the toilet, but combined with Tornado Flush it keeps the bowl noticeably cleaner between cleanings than a plain vitreous china finish.
The Aquia IV is a two-piece toilet with a separate tank and bowl, which keeps each piece lighter to carry and install. Its low-profile tank and fully skirted base give it a sleek, almost one-piece appearance, but the tank-to-bowl seam is present. Buyers wanting a true seamless one-piece dual-flush look may prefer a model like the Woodbridge T-0019.
The Drake is a single-flush toilet that posts a maximum 1000 gram MaP score on 1.28 gallons every flush, prioritizing raw clearing power. The Aquia IV is a dual-flush toilet that averages around 0.9 gallons and posts a strong 800 gram score, prioritizing water savings and bowl cleanliness. Choose the Drake for maximum power, the Aquia IV for efficiency.
The most common causes are a misadjusted dual-flush valve or a worn flush-valve seal. The dual-flush mechanism is slightly more complex than a single flapper, so check that the buttons and the valve return cleanly to seat after each flush. TOTO sells replacement parts for the Aquia line, and reseating or replacing the valve seal resolves most running and weak-flush complaints.
Use the large button, which releases the full 1.28 gallons, for solid waste. The small button releases 0.8 gallons and is designed for liquid and light paper only. Using the full flush for solids is what lets the toilet hit its 800 gram MaP rating, and using the small flush for liquids is what delivers the 0.9 gallon average.
Yes. Its low-profile tank and compact skirted body give it a smaller visual footprint than a tall traditional toilet, and the smooth skirt makes it easy to clean in tight spaces. The elongated bowl projects a little more than a round bowl, so measure your clearance, but overall the Aquia IV is a strong fit for compact and modern bathrooms.
No. Like other TOTO gravity toilets it is quieter than a pressure-assisted model, and the swirling Tornado Flush is a gentle, low-noise rinse rather than a sudden high-volume rush. Most owners describe it as a quiet, smooth flush, which makes it a reasonable pick for bathrooms next to bedrooms or shared living spaces.
Yes. TOTO backs the Aquia IV with its standard limited warranty, typically one year on the toilet from the date of purchase, with the brand's well-regarded parts availability and support behind it. Register your toilet, keep proof of purchase, and confirm the exact warranty terms on the specific model you buy, as coverage can vary by SKU and region.
The TOTO Aquia IV does two things better than almost any toilet in its price class: it sips water and it keeps the bowl clean. Its dual-flush 0.8 and 1.28 gallon buttons average around 0.9 gallons, the Tornado Flush rim jets rinse the whole bowl without a single rim hole, and the CeFiONtect glaze and fully skirted body make it one of the easiest toilets to wipe down, all backed by TOTO's reputation for reliability and WaterSense certification. The honest catch is flush power: its 800 gram MaP score is strong but not the 1000 gram maximum of a single-flush Drake or Champion 4, so very heavy users may occasionally double-flush. For an eco-minded household, a water-conscious region, or anyone tired of scrubbing skid marks, the Aquia IV is one of the easiest premium recommendations in the dual-flush category. Check the current price on Amazon to see where it lands today.
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