Washlet Toilet Reviews: Toto Aquia IV Water-Saving Toilet Features

Last Updated on October 20, 2026

Are you considering upgrading your bathroom with one of the most comfortable and luxurious modern toilets on the market? Take a look at the TOTO Aquia IV toilet series. These toilets combine a modern appearance, powerful flushing, and water-saving features to make everyday bathroom use more convenient.

The TOTO Aquia IV is the fourth generation of the Aquia toilet series. It offers several improvements in bowl design, cleaning performance, and compatibility with TOTO’s electronic WASHLET bidet seats.

Depending on the model and WASHLET configuration, the TOTO Aquia IV offers the following features:

• PREMIST: Wets the bowl surface before use to help reduce waste buildup.
• EWATER+: Automatically cleans the wand and, on compatible models, the bowl.
• CEFIONTECT glaze: Helps prevent waste and particles from sticking to the ceramic surface.
• DYNAMAX TORNADO FLUSH: Uses a powerful, circular flow of water to rinse the bowl.
• EPA WaterSense: Selected models are certified for efficient water consumption.
• CALGreen compliance: Meets applicable California water-efficiency requirements.
• Universal Height: Available configurations offer a comfortable seating position for many adults.

The TOTO Aquia toilet has been a popular choice among homeowners looking for an attractive, water-efficient toilet. The Aquia IV continues this design with a fully skirted bowl, an elongated seating area, and several WASHLET-compatible options.

In this TOTO Aquia IV review, we’ll compare two configurations, explain their advantages and disadvantages, and help you decide which one is suitable for your bathroom.

Related: TOTO Aquia II Review

2 Top-Rated TOTO Aquia IV Toilets Comparison Chart

The Aquia IV collection includes more than two configurations. However, the following two models are worth comparing because they offer different levels of water efficiency and convenience.

The standard Aquia IV uses 1.28 or 0.8 gallons per flush, while the Aquia IV 1G WASHLET+ S550e uses 1.0 or 0.8 gallons per flush.

TOTO Aquia IV WASHLET Dual Flush Toilet Review

The TOTO MS446124CEMG#01 Aquia IV is a stylish, two-piece toilet featuring the DYNAMAX TORNADO FLUSH system. This technology creates a circular flow of water that helps rinse the entire bowl efficiently.

It offers two flushing options: 1.28 GPF for a full flush and 0.8 GPF for a partial flush. As a result, you can use less water when flushing liquid waste without sacrificing the stronger full-flush option.

This dual-flush toilet also features TOTO’s CEFIONTECT glaze, which helps prevent debris from sticking to the ceramic surface.

Technical Specifications of the TOTO Aquia IV (Model: MS446124CEMG#01)

Powerful Flush and Attractive Appearance

One of the most appealing features of this TOTO Aquia IV toilet is its fully skirted design. Unlike traditional toilets with exposed trapways, the Aquia IV has smooth exterior sides that are easier to wipe clean.

The DYNAMAX flushing mechanism is also designed to provide effective bowl rinsing with reduced flushing noise. However, actual sound levels depend on water pressure and installation conditions.

Its elongated bowl offers comfortable seating, while the included SoftClose seat prevents the lid from slamming shut.

Water-Efficient and WASHLET-Compatible

This model is EPA WaterSense certified and meets applicable plumbing and water-efficiency standards. It is an attractive choice for homeowners who want to reduce toilet water consumption.

Although the name is sometimes associated with WASHLET compatibility, the MS446124CEMG includes a regular SoftClose seat, not an electronic WASHLET bidet. A compatible WASHLET and the required adapter must be purchased separately.

Pros of the TOTO Aquia IV Dual Flush Toilet

• Durable vitreous china construction
• Efficient 1.28/0.8 GPF dual-flush system
• Comfortable elongated bowl
• Fully skirted design makes exterior cleaning easier
• DYNAMAX TORNADO FLUSH provides effective bowl rinsing
• CEFIONTECT glaze helps reduce waste adhesion
• SoftClose seat included
• EPA WaterSense certified
• Compatible with selected electronic WASHLET seats

What Are the Drawbacks?

• The skirted design may require additional care during installation.
• Hard-water deposits can still develop despite the CEFIONTECT glaze.
• The electronic WASHLET seat is not included.
• Replacement flush-button components may cost more than basic toilet parts.

TOTO Aquia IV WASHLET+ 1G Two-Piece Toilet Review

TOTO manufactures some of the most innovative smart toilets available. The TOTO Aquia IV 1G WASHLET+ S550e is a good example of its focus on comfort, hygiene, and water efficiency.

The correct model designation for this configuration is MW4463056CUMG#01. It combines the Aquia IV two-piece toilet with the S550e electronic bidet seat.

Unlike the standard model, this premium two-piece toilet includes electronic washing functions, a heated seat, automatic lid operation, and other comfort features.

Modern WASHLET+ Toilet

If you want to improve your bathroom’s appearance and convenience, the Aquia IV WASHLET+ is worth considering. Its skirted design gives it a clean, modern appearance, while the elongated bowl provides comfortable seating.

The included S550e offers automatic lid opening and closing, adjustable warm-water cleansing, a heated seat, warm-air drying, deodorizing, and a nightlight.

These functions can reduce your dependence on toilet paper and make everyday bathroom use more comfortable. However, some users may still prefer a small amount of toilet paper after drying.

Technical Specifications of the TOTO Aquia IV WASHLET+ (Model: MW4463056CUMG#01)

Easy to Maintain

Cleaning and maintaining this 1-gallon WASHLET+ is relatively simple. Its PREMIST function wets the bowl before use, making it harder for waste to stick to the ceramic surface.

The EWATER+ system automatically cleans the wand and bowl, while the CEFIONTECT glaze reduces waste adhesion.

Together, these features help keep the toilet cleaner between regular cleaning sessions. However, they do not eliminate the need for routine cleaning.

Related: TOTO G400 WASHLET Toilet Review

The Flushing System Is Quiet and Water-Efficient

The Aquia IV 1G uses the DYNAMAX TORNADO FLUSH system with two water-saving options. A partial flush uses 0.8 gallons, while a full flush uses 1.0 gallon.

This ultra-high-efficiency toilet is EPA WaterSense certified and meets applicable California water-efficiency requirements.

The standard model uses a manual top-mounted flush button. Automatic flushing is available on the appropriate upgraded configuration.

2026 buying consideration: TOTO also offers newer Aquia IV WASHLET+ configurations with S7, S7A, C5, and C2 electronic seats. These newer combinations may be more suitable if you are looking for current WASHLET technology, but their flushing rates and features vary by model.

Pros of the TOTO Aquia IV 1G WASHLET+ S550e

• Automatic opening and closing lid
• Adjustable heated seat for comfort
• Powerful and relatively quiet DYNAMAX flushing system
• EWATER+ automatically cleans the wand and bowl
• Integrated nightlight
• CEFIONTECT helps reduce waste adhesion
• Ultra-efficient 1.0/0.8 GPF dual flush
• PREMIST helps prevent waste buildup
• Warm-water washing and air drying
• Elegant skirted design with concealed WASHLET connections

Negative Reviews and Drawbacks

• More expensive than a conventional two-piece toilet
• Electronic bidet functions require electricity
• Installation may require a nearby GFCI-protected electrical outlet
• Some electronic components can be expensive to replace
• Finding older S550e packages may be harder as newer WASHLET options become available

Maintenance Tips for the TOTO Aquia IV Toilet

• Regular cleaning: Use a soft cloth and mild, non-abrasive cleaner. Avoid harsh chemicals that could damage the CEFIONTECT finish.
• Check the flush mechanism: Inspect the dual-flush valve seal and fill valve if you notice continuous running or weak flushing.
• Maintain water flow: Clean accessible bowl outlets gently to remove mineral deposits.
• Prevent hard-water stains: Remove mineral deposits using products approved for glazed ceramic surfaces. Avoid leaving acidic cleaners on the finish.
• Care for the seat: Clean the seat and hinges using the manufacturer’s recommended method.
• Use compatible replacement parts: Select components approved for your specific Aquia IV model.
• Check bolts and seals: Inspect the tank-to-bowl connection and floor mounting hardware for leaks or movement.
• Flush only appropriate waste: Avoid wipes, paper towels, and hygiene products, even when advertised as flushable.

TOTO Aquia IV vs. Nexus vs. Drake II Toilet

Not sure whether the Aquia IV is the best option? The following comparison highlights the major differences between the Aquia IV and two other popular TOTO toilet families.

The Aquia IV is an excellent choice if you prefer dual-flush water savings and a fully skirted exterior. The Nexus is suitable for homeowners wanting a sleek toilet with a conventional single-flush design. The Drake II is worth considering if you prefer a more traditional appearance and simpler exterior access.

You can also explore our TOTO Drake toilet review for additional information about that series.

TOTO Aquia IV Installation: What Should You Check?

Before purchasing a TOTO Aquia IV toilet, measure the rough-in distance from the finished wall to the center of the floor drain.

The standard configuration uses a 12-inch rough-in. Optional 10-inch and 14-inch UniFit adapters are available for compatible installations.

Also check your water supply valve location. The skirted bowl requires specific clearances, and TOTO recommends an appropriate 90-degree stop valve.

If you’re buying the WASHLET+ version, make sure a properly installed electrical outlet is available near the toilet. Always follow the model-specific installation instructions.

Troubleshooting Table for TOTO Aquia IV Toilets

Conclusion: Is the TOTO Aquia IV Worth Buying?

The TOTO Aquia IV toilet series offers attractive designs, dependable flushing performance, and several convenient features.

If you want a straightforward, water-efficient toilet, the MS446124CEMG with 1.28/0.8 GPF dual flushing is a practical option. It provides a comfortable elongated bowl, a SoftClose seat, and an easy-to-clean skirted exterior.

For greater comfort and hygiene, the Aquia IV 1G WASHLET+ S550e provides warm-water cleaning, automatic lid operation, a heated seat, and a more water-efficient 1.0/0.8 GPF flush.

However, buyers in 2026 should also compare the newer Aquia IV WASHLET+ S7 and S7A configurations before selecting an older S550e package.

Overall, this TOTO Aquia IV review should help you choose the right model based on your bathroom layout, budget, and preferred features.

Frequently Asked Questions

What does ADA-compliant toilet height mean?

ADA accessibility standards generally specify a toilet seat height of 17 to 19 inches above the finished floor for accessible water closets. However, seat height alone does not make a toilet installation fully ADA-compliant. Flush controls, surrounding clearances, and other installation requirements also matter.

What is a TOTO WASHLET bidet seat?

WASHLET is TOTO’s name for its electronic bidet seats. Depending on the model, they provide warm-water cleansing, heated seating, air drying, deodorizing, and other functions. WASHLET+ versions are designed to integrate more neatly with compatible TOTO toilets.

Do I need to check my water supply line before purchasing a skirted toilet?

Yes. The Aquia IV’s skirted base can interfere with water supply valves installed in unsuitable positions. Check the manufacturer’s rough-in diagram and supply valve clearance requirements before ordering.

Does every TOTO Aquia IV include PREMIST and EWATER+?

No. These electronic cleaning functions are provided by compatible WASHLET bidet seats. The standard Aquia IV with a regular SoftClose seat does not include them.

Does the TOTO Aquia IV require electricity?

The standard toilet flushes without electricity. However, electronic WASHLET features require electrical power. During a power outage, the toilet can generally still be flushed manually if the water supply is functioning.

Is the TOTO Aquia IV difficult to install?

Installation is manageable for an experienced plumber, but the skirted design, UniFit adapter, and supply valve requirements make it more involved than installing some traditional toilets. WASHLET+ models also require a suitable electrical connection.