TOTO toilets are known for their reliable flushing performance, durable construction, and attractive designs. Whether you prefer a one-piece toilet, a two-piece model, or an elongated bowl, TOTO offers several options.
In this TOTO Aquia II review, we’re going to discuss the design, flushing performance, comfort, installation, and other features of the TOTO Aquia II CST416M toilet.
The Aquia II shares several features with the original TOTO Aquia toilet. However, the Aquia II has its own design and dimensions. Both models use the Dual-Max flushing system, which offers two different flushing options to help conserve water.
The Aquia II is a two-piece toilet made of vitreous china. It features a regular-height elongated bowl, concealed trapway, and chrome-plated dual-flush buttons.
The toilet uses 0.9 gallons per flush for liquid waste and 1.6 gallons per flush for solid waste. This makes it a practical choice for homeowners who want to reduce water consumption without giving up effective flushing performance.
Although the original Aquia II is an older model, it can still be worth considering in 2026 if you find one at a reasonable price. However, availability may be limited, so it’s important to compare it with newer Aquia models before purchasing.
Related: Best Dual-Flush Toilet Reviews
TOTO Aquia II Dual-Flush Toilet Review in 2026
The TOTO Aquia II combines a modern concealed-trapway design with a water-saving Dual-Max flushing system. Its elongated bowl provides comfortable seating, while the smooth exterior makes cleaning easier than with many traditional exposed-trapway toilets.
The toilet is also EPA WaterSense certified. However, its actual water savings depend on how often you use each flush setting and the efficiency of your previous toilet.
If you’re comparing different generations of this toilet, our Aquia, Aquia II, Aquia III, and Aquia IV comparison explains their main differences.
Product Description
- Two-piece toilet construction
- Regular-height elongated bowl
- Dual-Max flushing system
- 0.9 GPF partial flush and 1.6 GPF full flush
- Concealed-trapway design
- Vitreous china construction
- Chrome-plated dual-flush push buttons
- EPA WaterSense certification
- Standard 12-inch rough-in
- One-year limited warranty
Technical Specifications of the TOTO Aquia II
| Features | TOTO Aquia II CST416M |
|---|---|
| Material | Vitreous china |
| Construction | Two-piece toilet |
| Water Consumption | 0.9 GPF / 1.6 GPF |
| Bowl Shape | Elongated |
| Bowl Height | Standard height, approximately 15-3/8 inches |
| Color Options | Cotton, Bone, Colonial White, Sedona Beige, and Ebony |
| Flush Type | Dual flush |
| Flushing System | Dual-Max gravity flush |
| Rough-In | 12 inches |
| Trapway | Concealed, 2-1/8-inch diameter |
| Flush Control | Chrome-plated top-mounted push buttons |
| Certification | EPA WaterSense, IAPMO/cUPC |
| ADA Compliance | Not ADA compliant in its standard configuration |
| Minimum Water Pressure | 8 PSI (static) |
| Approximate Dimensions | 27-5/8″ D × 15-3/8″ W × 30-3/8″ H |
| Shipping Weight | Bowl: 66.5 lbs.; tank: 30 lbs. |
| Seat Included | No; compatible seat sold separately |
| Warranty | One-year limited warranty |
| Price |  Check Price and Availability |
Benefits of the TOTO Aquia II Dual-Flush Toilet
Sturdy Construction
The TOTO Aquia II is manufactured using vitreous china, a strong ceramic material commonly used in quality bathroom fixtures.
Its glazed surface resists moisture and is easy to maintain. With proper installation and regular maintenance, the toilet can provide many years of reliable service.
The two-piece design also makes transportation and installation more manageable because the tank and bowl can be handled separately.
However, vitreous china can crack if mounting bolts are overtightened or the toilet is subjected to a strong impact.
High-Efficiency Dual-Max Flushing System
One of the best features of the TOTO Aquia II is its Dual-Max flushing technology.
Unlike single-flush toilets, which use the same amount of water every time, the Aquia II allows users to choose between two flushing volumes.
- Partial Flush: Uses 0.9 gallons for liquid waste.
- Full Flush: Uses 1.6 gallons for solid waste.
The flushing system uses gravity to move water through the bowl and trapway. The full-flush setting provides more water when additional flushing power is needed.
If half of your flushes use each setting, the average water consumption is approximately 1.25 gallons per flush.
Although the Aquia II is designed for efficient waste removal, occasional double flushing may still be necessary depending on usage and maintenance conditions.
Design and Style
If you’re looking for a stylish toilet that complements a modern bathroom, the Aquia II is an attractive option.
It features an elongated bowl and concealed trapway, giving the toilet a smooth and elegant appearance.
Unlike traditional exposed-trapway toilets, its sides have fewer hard-to-reach curves. This makes it easier to wipe down during regular bathroom cleaning.
The Cotton White finish blends well with most bathroom fixtures, although several other colors were also offered.
However, its regular-height bowl may not be the best choice for taller adults or people who have difficulty standing up from lower seats.
If you prefer a taller toilet, consider comparing comfort-height toilet models.
Related: TOTO Drake II Two-Piece Toilet Review
Less Water Usage
Water efficiency is one of the main reasons to choose a dual-flush toilet.
Since the Aquia II uses only 0.9 gallons for a partial flush, you don’t need to use the full 1.6 gallons every time.
For example, if a household performs 20 flushes per day and uses the partial-flush setting for half of them, the toilet would consume approximately 25 gallons daily.
Under the same conditions, a conventional 1.6 GPF single-flush toilet would consume 32 gallons.
That represents a potential saving of around 2,555 gallons annually.
The Aquia II is EPA WaterSense certified. Some local utilities offer rebates for qualifying water-efficient toilet installations, although availability and eligibility vary by location.
Easy Cleaning and Maintenance
The TOTO Aquia II is relatively easy to clean because of its smooth ceramic surface and concealed-trapway design.
The exterior has fewer exposed curves where dust and dirt can collect. Regular wiping with a soft cloth and a suitable bathroom cleaner is usually sufficient.
However, the standard CST416M should not be confused with newer Aquia models featuring CEFIONTECT glaze or DYNAMAX TORNADO FLUSH.
Its Dual-Max flushing system helps remove waste, but routine bowl cleaning is still necessary to prevent mineral deposits and stains.
Avoid abrasive brushes and harsh cleaning chemicals that may damage the toilet’s finish or internal components.
Easy Installation
Installing the TOTO Aquia II is manageable for an experienced DIY homeowner, although its concealed-trapway design requires more careful positioning than some traditional toilets.
The toilet uses a standard 12-inch rough-in, measured from the finished wall to the center of the floor drain.
Since the tank and bowl are separate, you can install the bowl first and attach the tank afterward.
Before installation, make sure you have the correct toilet mounting hardware, sealing components, water supply connection, and compatible seat.
The toilet seat is not included in the standard manufacturer’s configuration. TOTO lists several compatible SoftClose seats, including SS114, SS154, and SS204.
Professional installation is recommended if you need to adjust the water supply location or repair the closet flange.
Recap: Why Buy the TOTO Aquia II Two-Piece Dual-Flush Toilet?
We’ve covered the main features of the TOTO Aquia II review. Before deciding whether to purchase it, consider the following advantages and drawbacks.
Pros
- Attractive two-piece design that complements modern bathrooms.
- Concealed trapway makes exterior cleaning easier.
- Durable vitreous china construction.
- Water-efficient 0.9 and 1.6 GPF flushing options.
- Comfortable elongated bowl.
- EPA WaterSense certified.
- Separate tank and bowl simplify handling during installation.
- Compatible with selected TOTO SoftClose seats.
- One-year limited manufacturer’s warranty.
Cons
- The regular-height bowl may be uncomfortable for some taller adults.
- Not ADA compliant in its standard configuration.
- A compatible toilet seat must be purchased separately unless included in a retailer bundle.
- The concealed-trapway design can make installation more involved.
- Replacement parts and complete units may be harder to find because it is an older model.
- It lacks some advanced cleaning features available on newer TOTO toilets.
TOTO Drake II vs. Aquia II Comparison
The TOTO Drake II and Aquia II are both two-piece toilets, but they use different flushing systems and have different design priorities.
| Feature | TOTO Drake II | TOTO Aquia II CST416M |
|---|---|---|
| Type | Two-piece toilet | Two-piece toilet |
| Flushing System | Double Cyclone/TORNADO FLUSH, depending on version | Dual-Max |
| Water Consumption | Typically 1.28 GPF | 0.9 / 1.6 GPF |
| Bowl Shape | Elongated | Elongated |
| Height | Universal Height on common models | Regular height |
| Trapway Design | Exposed on common models | Concealed |
| Flush Control | Trip lever | Top-mounted dual buttons |
| WaterSense | Yes, on qualifying models | Yes |
| Best For | Comfortable seating and single-flush simplicity | Dual-flush water savings and modern styling |
Which is better? The Aquia II is suitable if you prefer dual-flush operation and a concealed trapway. The Drake II may be a better option if you want a taller seating position and simpler single-flush operation.
Common Troubleshooting Table for the TOTO Aquia II Toilet
| Issue | Possible Cause | Solution |
|---|---|---|
| Weak Flush Performance | Low tank water level, partially clogged trapway, or flush mechanism problems. | Check the tank water level and inspect the flush valve. Remove blockages using a toilet auger if necessary. |
| Continuous Water Running | Worn flush-valve seal, debris, or incorrect valve adjustment. | Inspect and clean the flush-valve seal. Replace worn parts using the correct TOTO components. |
| Leaking Around the Base | Damaged floor seal, loose mounting hardware, or improper installation. | Stop using the toilet, inspect the seal and mounting system, and repair the leak before water damages the floor. |
| Tank Not Filling | Closed supply valve, blocked inlet filter, or faulty fill valve. | Check the water supply and inspect the fill valve. Clean or replace the faulty component as needed. |
| Unstable Toilet | Uneven floor, loose mounting hardware, or incorrect seating on the flange. | Inspect the installation, use appropriate shims when necessary, and avoid overtightening bolts. |
| Dual-Flush Buttons Not Working | Misaligned button assembly or faulty flush-valve mechanism. | Check the push-button assembly and replace damaged components with compatible TOTO parts. |
Is the TOTO Aquia II Worth Buying in 2026?
The TOTO Aquia II still offers several useful features, including a durable ceramic construction, comfortable elongated bowl, and efficient dual-flush operation.
However, it is an older toilet model, and replacement parts or complete units may be harder to find than those for newer Aquia versions.
If you find the CST416M at a reasonable price and confirm the availability of essential replacement parts, it can still be a good bathroom upgrade.
Otherwise, newer Aquia models may offer better value through improved flushing systems, updated designs, and additional cleaning features.
Bottom Line
The TOTO Aquia II is a well-designed two-piece toilet with a concealed trapway, elongated bowl, and efficient Dual-Max flushing system.
Its 0.9 and 1.6 GPF flush options allow homeowners to conserve water while maintaining practical flushing performance.
The main drawbacks are its standard-height bowl, separate seat purchase, and limited availability in some markets.
Overall, our TOTO Aquia II review finds it a worthwhile option for buyers who want traditional dual-flush technology and sleek bathroom styling. Just compare it with newer Aquia models before making your final decision.
Frequently Asked Questions
1. Do I have to change my water supply line because the TOTO Aquia II has a concealed trapway?
Not necessarily. The Aquia II is designed for a standard 12-inch rough-in, but you should check the existing water supply location against TOTO’s installation diagram. Some bathrooms may require minor plumbing adjustments.
2. Does the TOTO Aquia II come with a toilet seat?
No. The original CST416M does not include a seat in the manufacturer’s standard configuration. Compatible TOTO SoftClose models include the SS114, SS154, and SS204. Some retailers may offer packages with a seat included.
3. Is the TOTO Aquia II ADA compliant?
No. The standard Aquia II CST416M is not ADA compliant. Its regular-height bowl and top-mounted push buttons do not meet all applicable accessibility requirements.
4. What is the difference between the TOTO Aquia and Aquia II?
Both models use Dual-Max technology and offer 0.9 and 1.6 GPF flushing options. However, their designs, dimensions, bowl heights, and installation requirements differ.
5. Can I install a TOTO WASHLET on the Aquia II?
Yes, selected WASHLET models can be installed on the Aquia II using the appropriate connections. TOTO specifies the THU9090R adapter hose kit for WASHLET installation. Always verify the exact WASHLET compatibility before purchasing.
6. Is the TOTO Aquia II discontinued?
The Aquia II CST416M is an older model, and complete toilet availability may be limited in 2026. Some replacement parts remain identifiable through TOTO’s parts documentation. Check with an authorized retailer before purchasing.
7. What rough-in size does the Aquia II require?
The standard Aquia II CST416M requires a 12-inch rough-in. Measure from the finished wall to the center of the toilet flange before installation.
8. Does the TOTO Aquia II have CEFIONTECT glaze?
The standard CST416M specifications do not list CEFIONTECT or SanaGloss as a standard feature. These finishes are available on selected other TOTO models, so check the exact product specifications rather than assuming they are included.
9. How long is the TOTO Aquia II warranty?
The original Aquia II comes with a one-year limited manufacturer’s warranty. Coverage is subject to TOTO’s warranty terms and applicable purchase conditions.
10. Where can I find TOTO Aquia II replacement parts?
You can identify compatible components using the TOTO Aquia II CST416M replacement parts diagram. Common replacement items include the fill valve, flush-valve seals, dual-flush button assembly, and tank-to-bowl gasket.
For more choices, explore our toilet reviews and buying guides.
Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.