Choosing between the TOTO Aquia IV and the TOTO Nexus is one of the trickiest decisions you’ll face when upgrading your bathroom.
Both toilets are built to impress, but they serve slightly different buyers — and this guide helps you figure out which one is right for you.
| Feature | TOTO Aquia IV Two-Piece | TOTO Nexus Two-Piece |
|---|---|---|
| Image | [Image loads via plugin] |  |
| Dimensions (D x W x H) | 27.6″ x 15.6″ x 29.6″ | 28.6″ x 18.5″ x 28.7″ |
| Flush System | DYNAMAX TORNADO FLUSH (360°) | TORNADO FLUSH (dual nozzle) |
| Flush Volume | 1.28 / 0.9 GPF (dual flush) | 1.28 GPF (single flush) |
| CEFIONTECT Glaze | Yes | Yes |
| Design Style | Contemporary skirted | High-profile skirted |
| WASHLET+ Compatible | Yes (T40) | Yes (T40) |
| Rough-In Size | 12″ (adapter for 10″ / 14″) | 12″ (adapter for 14″) |
| Buy Now |  |
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1. TOTO Aquia IV Two-Piece Elongated Dual Flush Toilet
The TOTO Aquia IV is a dual-flush powerhouse with a sleek contemporary design built for the water-conscious homeowner.
It gives you the choice between a 0.9 GPF light flush and a 1.28 GPF full flush — a rare feature in this class that can make a real difference on your water bill over time.
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Features
- DYNAMAX TORNADO FLUSH with 360° rim-to-bowl cleaning power
- Dual flush: 0.9 GPF and 1.28 GPF push-button selector on tank lid
- Fully skirted design conceals the trapway for a seamless look
- CEFIONTECT ceramic glaze prevents debris from sticking
- WASHLET+ T40 compatible — hides power cords and supply hose
- Adapts to 10″, 12″, or 14″ rough-in
Pros
- Dual flush saves significant water versus single-flush models
- Quieter flush due to improved inner bowl design reducing turbulence
- Wider rough-in compatibility than the Nexus
- Low-profile contemporary look fits modern bathrooms beautifully
Cons
- Narrower at 15.6″ wide — could feel tight for some users
- Dual-flush push button takes some getting used to
If water savings and versatile installation options are priorities for you, the Aquia IV is nearly impossible to beat at this price point. It pairs flawlessly with a TOTO WASHLET bidet seat if you want to level up your bathroom hygiene — you can explore the best options in our best bidets for home use guide.
Check its current price on Amazon
2. TOTO Nexus Two-Piece Elongated 1.28 GPF Toilet
The TOTO Nexus is a high-profile, elegantly skirted toilet that makes a bold visual statement while delivering everything you’d expect from a premium TOTO model.
It uses a dual-nozzle TORNADO FLUSH system that creates a powerful centrifugal rinse, keeping the bowl cleaner with every flush without the need for constant scrubbing.
Features
- TORNADO FLUSH with dual-nozzle centrifugal cleaning action
- Single flush at 1.28 GPF — WaterSense certified
- High-profile skirted bowl design with a tall, refined silhouette
- CEFIONTECT ceramic glaze for mold and debris resistance
- WASHLET+ T40 compatible with auto-flush readiness
- Universal Height for comfortable seating across all ages
- ADA compliant
Pros
- Taller, high-profile look elevates the aesthetic of any bathroom
- ADA compliant — great for seniors or those with mobility needs
- Wider bowl at 18.5″ offers a roomier seating experience
- Simpler single-flush mechanism — no buttons to overthink
Cons
- Single flush only — no option to conserve water on lighter loads
- Rough-in adapter only available for 14″ (not 10″)
The Nexus is a great choice if you want a toilet that makes a visual impact and doubles as an ADA-accessible fixture. It also pairs beautifully with a WASHLET bidet seat — our heated bidet toilet seat roundup has plenty of compatible picks to consider.
Check its current price on Amazon
Flush Performance: Which One Cleans Better?
Both toilets use TOTO’s signature TORNADO FLUSH technology, so neither is going to leave you disappointed.
The Aquia IV uses the upgraded DYNAMAX TORNADO FLUSH, which draws water from the full 360° of the rim for a more comprehensive rinse.
The Nexus uses a dual-nozzle version that creates powerful centrifugal action — highly effective, but slightly more targeted than the Aquia IV’s approach.
Winner: Aquia IV — the DYNAMAX system edges out the dual-nozzle design for sheer bowl coverage.
Water Efficiency: Single vs Dual Flush
This is one of the most important differences between these two toilets.
The Aquia IV gives you a dual-flush option: a full 1.28 GPF flush and a lighter 0.9 GPF rinse for liquid waste.
The Nexus uses a single 1.28 GPF flush every time, which is still WaterSense certified and efficient by any standard.
If cutting your water usage is a priority — and it should be, given how much you can save over time, as explored in our guide on bidets vs toilet paper — the Aquia IV’s dual flush gives you a meaningful edge.
Winner: Aquia IV — dual flush wins for water conservation.
Design and Aesthetics: Contemporary vs High-Profile
Both toilets feature a skirted design that conceals the trapway — making them both easier to clean than traditional exposed-trapway toilets.
The Aquia IV has a lower, more contemporary profile that blends into modern minimalist bathrooms without drawing too much attention.
The Nexus has a taller, high-profile silhouette that makes more of a statement — it’s the kind of toilet that genuinely upgrades the look of your bathroom.
If you want your toilet to be a design feature, the Nexus wins.
Winner: Nexus — the high-profile look stands out for style-conscious buyers.
Comfort and Accessibility
The Nexus is explicitly ADA compliant and designed at Universal Height for maximum comfort across a wide range of users.
At 18.5″ wide and with a bowl height of 16.1″, it’s noticeably roomier and more chair-like than the Aquia IV’s 15.6″ width.
The Aquia IV sits slightly lower and narrower, which some users prefer — but for seniors or anyone with mobility challenges, the Nexus is the safer choice.
You can also read our guide to the best bidets for seniors to find a WASHLET seat that complements the Nexus perfectly.
Winner: Nexus — wider seat, ADA compliance, and Universal Height make it the accessibility winner.
Installation Flexibility
The Aquia IV is the more flexible toilet when it comes to rough-in sizing.
It fits a standard 12″ rough-in right out of the box and can be adapted to 10″ or 14″ with separately sold adapters.
The Nexus fits a 12″ rough-in but can only be adapted to 14″ — not 10″.
If you’re working with an older home that has non-standard rough-in dimensions, the Aquia IV offers you more options.
Winner: Aquia IV — broader rough-in compatibility gives it the installation edge.
Verdict — Which One Should You Buy?
Both of these toilets are excellent choices, but they’re built for slightly different buyers.
Buy the TOTO Aquia IV if… you want to maximize water savings, you need a more compact toilet, your home has a 10″ rough-in, or you prefer a lower contemporary profile. It’s also the smarter pick if you want versatile WASHLET+ upgradability and a quieter flush — pair it with one of the picks from our bidet toilet seat comparison chart to get the best of both worlds.
Buy the TOTO Nexus if… you care about bold aesthetics, you want ADA accessibility, or you need a roomier seat for maximum comfort. It’s also the right pick if you don’t want to think about which flush mode to use each time. Those who want a complete toilet-bidet combo should also browse our best toilets with built-in bidet roundup for integrated alternatives.
FAQ
Is the TOTO Aquia IV better than the Nexus for water savings?
Yes. The Aquia IV’s dual-flush system (1.28 / 0.9 GPF) lets you use less water for liquid waste, whereas the Nexus uses a fixed 1.28 GPF for every flush. Over time, the dual flush can lead to meaningful reductions in water usage.
Can I add a TOTO WASHLET bidet seat to both of these toilets?
Yes, both the Aquia IV and Nexus are TOTO T40 WASHLET+ compatible. This means a bidet seat can be installed with completely concealed hoses and power cords for a seamless, integrated look. You can explore our list of best bidets for existing toilets for compatible options.
Which toilet is better for older adults or those with mobility issues?
The TOTO Nexus is the better choice. It’s ADA compliant, designed at Universal Height, and has a wider 18.5″ bowl that makes sitting and standing easier. Check our bidet guide for seniors to complete the setup with an accessible WASHLET seat.
What is the difference between DYNAMAX TORNADO FLUSH and TORNADO FLUSH?
Both systems use a rimless design for powerful, hygienic bowl cleaning. The DYNAMAX version found in the Aquia IV draws water from the full 360° of the bowl rim for a more comprehensive rinse, while the standard TORNADO FLUSH in the Nexus uses two powerful nozzles for centrifugal cleaning action. Both perform excellently in real-world use.
Conclusion
The TOTO Aquia IV and TOTO Nexus are two of the best TOTO toilets you can buy — and you genuinely can’t go wrong with either.
If water efficiency and installation flexibility matter most to you, the TOTO Aquia IV is your pick.
If you want ADA compliance, a roomier seat, and a bolder aesthetic, the TOTO Nexus won’t disappoint.
Either way, both toilets are ready for a WASHLET bidet upgrade the moment you decide you want one — which, based on our experience at BideTalk, is usually sooner than you expect. Head over to our best bidet brands guide to learn more about what TOTO offers across its full lineup.
