A dual-flush toilet lets you choose between a lower-volume flush for liquid waste and a higher-volume flush for solids. The right model can help reduce water use, but fit, seat height, bowl shape, and flushing design matter just as much. These five options range from a compact one-piece toilet to a traditional two-piece model, with different dimensions and flush volumes to compare before you buy.
Check your bathroom’s rough-in measurement and available space first. Also note whether a seat is included: one option below is sold without one, while the others list a seat as part of the package.
Table of Contents
Quick Comparison
| Toilet | Design and bowl | Dual-flush options | Notable details |
|---|---|---|---|
| Gerber Maxwell Select Round Two-Piece Toilet | Two-piece, round | 1.0 / 1.28 GPF | Soft-close seat included; glazed trapway |
| HOROW T0338W One-Piece Toilet | One-piece, elongated | 1.1 / 1.6 GPF | 17.3-inch seat height; 10- or 12-inch rough-in versions |
| American Standard H2Option Two-Piece Toilet | Two-piece, elongated front | 0.92 / 1.28 GPF | Seat sold separately; WaterSense and MaP Premium criteria listed |
| DeerValley Elongated One-Piece Toilet | One-piece, elongated | 1.1 / 1.6 GPF | Standard-height seat; 12-inch rough-in |
| Casta Diva Elongated One-Piece Toilet | One-piece, elongated | 1.1 / 1.6 GPF | 17-inch seat height; seat, wax seal, and hardware included |
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Gerber Maxwell Select: A Round-Bowl Pick for Smaller Bathrooms
The Gerber Maxwell Select is a conventional two-piece toilet with a round bowl. Its 1.0- and 1.28-gallon flush choices are the lowest listed options among these five models, which may appeal if water use is a priority. The canister flush valve and glazed trapway are designed to support a strong flush and help waste move through the toilet.
A round bowl can be useful when bathroom space is tight, though it may feel less roomy than an elongated bowl. The included slow-close seat is a practical convenience, and the two-piece design keeps the tank and bowl separate. Compared with the one-piece choices here, it has a more traditional shape and may involve more exposed seams to clean.
The product description calls out a water-saving flush and a smooth trapway, but it does not provide the toilet’s overall dimensions or seat height. Confirm that the bowl shape, rough-in, and fit work in your bathroom before ordering.
Pros:
- Round bowl can suit bathrooms where space is limited
- 1.0- and 1.28-GPF flush options
- Soft-close seat is included
- Glazed trapway and canister flush valve are designed for everyday use
Cons:
- Round bowl offers less front-to-back room than an elongated design
- Seat height and overall dimensions are not specified in the supplied details
Verdict: Choose the Gerber if you want a round-bowl, two-piece toilet with a low-volume flush option and included soft-close seat.
HOROW T0338W: A Compact Elongated Toilet with Chair-Height Seating
The HOROW T0338W combines a compact one-piece body with an elongated bowl. It measures 26.6 inches deep, 15 inches wide, and 26 inches high, making its listed dimensions useful for planning a tighter bathroom layout. The 17.3-inch seat height is intended to provide a chair-height feel that may make sitting down and standing up easier for some people.
Its dual-flush system uses 1.1 gallons for the lower-volume flush and 1.6 gallons for the higher-volume flush. The product description also lists siphon flushing and a fully glazed 2-inch trapway. A soft-closing seat is included, and the one-piece exterior has fewer seams between tank and bowl to wipe around than a two-piece toilet.
One detail to verify is the rough-in version. This model is offered in 10- and 12-inch configurations, so you need to select the one that matches the distance from the finished wall to the floor drain. Its elongated shape may also need more room in front of the bowl than a round model.
Pros:
- Compact listed dimensions with an elongated bowl
- 17.3-inch seat height and included soft-close seat
- Two flush volumes, 1.1 and 1.6 GPF
- Available in 10- and 12-inch rough-in versions
Cons:
- You must choose the correct rough-in version for your bathroom
- Elongated shape may need more front clearance than a round bowl
Verdict: The HOROW is a strong fit if you want an elongated one-piece toilet with chair-height seating, provided its dimensions and selected rough-in match your space.
American Standard H2Option: Low Flush Volumes in a Two-Piece Design
The American Standard H2Option is a two-piece toilet with an elongated-front bowl and a dual-flush mechanism rated at 0.92 and 1.28 gallons per flush. Those are the lowest listed flush volumes in this comparison. Its siphon jet bowl technology and PowerWash rim are designed to support waste removal and bowl cleaning.
The supplied product details say this model meets EPA WaterSense and MaP Premium criteria. These credentials can help shoppers compare water use and flushing performance, but they do not remove the need to check the toilet’s fit and installation requirements. The description identifies it as standard height, which may be less suitable if you specifically want chair-height seating.
Plan for the extra cost and effort of choosing a separate seat: one is not included. The product information also does not give dimensions or a rough-in measurement, so confirm those details before making it your replacement toilet.
Pros:
- 0.92- and 1.28-GPF flush options
- Elongated-front bowl
- Siphon jet technology and PowerWash rim are specified
- WaterSense and MaP Premium criteria are listed
Cons:
- Seat is sold separately
- Standard height may not suit shoppers seeking chair-height seating
Verdict: Consider the H2Option if lower listed flush volumes and its specified performance criteria are your priorities, and you are comfortable sourcing a separate seat.
DeerValley One-Piece: A Skirted Toilet with an Elongated Bowl
This DeerValley model has an elongated bowl, a one-piece body, and a skirted exterior. Its listed dimensions are 28.75 inches long, 14 inches wide, and 28 inches high. The smooth-sided design can be easier to wipe around than a toilet with more exposed contours, though its longer footprint calls for careful clearance checks.
The dual-flush system offers 1.1 and 1.6 GPF, and the product description gives a MaP rating of 800 grams. The seat height is listed as 16 7/8 inches, making it a standard-height option rather than a taller chair-height model. It uses a 12-inch rough-in, so it is not the flexible choice for a 10-inch rough-in bathroom.
The description also specifies a removable seat and glazed surface. These details make routine cleaning and seat replacement simpler in principle, but the available product information does not state whether the seat closes softly. If that feature matters to you, verify it before choosing this model.
Pros:
- One-piece, skirted design with an elongated bowl
- 1.1- and 1.6-GPF flush options
- Removable seat and glazed surface are specified
- Dimensions and 12-inch rough-in are provided for planning
Cons:
- Only a 12-inch rough-in is listed
- Standard seat height may not provide a chair-height feel
Verdict: Pick the DeerValley if you want a skirted one-piece toilet with an elongated bowl and your bathroom has a 12-inch rough-in.
Casta Diva: A One-Piece Toilet with a 17-Inch Seat Height
The Casta Diva is a skirted, one-piece toilet with an elongated bowl and a listed seat height of 17 inches. Its dimensions are 27.17 inches deep, 14.37 inches wide, and 25.39 inches high. The one-piece construction gives it a continuous exterior, while the included quick-release, slow-close seat is designed to lift off for cleaning and close quietly.
Its dual-flush settings are 1.1 GPF for liquid waste and 1.6 GPF for solid waste. The product description lists a MAP rating of 1000 and a fully glazed trapway. It also says the toilet meets EPA WaterSense criteria. The package is described as including a wax seal, installation hardware, and pre-installed fill and flush valves, which may reduce the number of separate parts you need to source.
This model uses a standard 12-inch rough-in. The product description says side holes provide access for floor-bolt installation, but you should still confirm the installation instructions and bathroom measurements before buying. Its 17-inch seat height may work well for shoppers seeking a taller seat, but comfort is personal, so compare it with your current toilet if possible.
Pros:
- 17-inch seat height and elongated bowl
- 1.1- and 1.6-GPF flush options
- Slow-close, quick-release seat is included
- Wax seal and installation hardware are listed as included
Cons:
- Requires a 12-inch rough-in
- Taller seating may not suit everyone
Verdict: The Casta Diva is a well-equipped option if you want an elongated one-piece toilet, a 17-inch seat height, and a package that includes key installation parts.
How to Choose the Best Dual-Flush Toilet
Measure the Rough-In Before You Compare Models
The rough-in is the distance from the finished wall behind the toilet to the center of the floor drain. A toilet with the wrong rough-in may not fit correctly, even if its bowl and style look right. The HOROW is listed in 10- and 12-inch versions, while the DeerValley and Casta Diva specify a 12-inch rough-in. For models without a rough-in listed in the supplied details, check the product specifications or installation guide before ordering.
Compare the Flush Volumes and Performance Details
Dual-flush toilets use different amounts of water for their lower- and higher-volume flushes. In this group, the listed options range from 0.92/1.28 GPF on the American Standard to 1.1/1.6 GPF on several one-piece models. Lower numbers do not tell the whole story, so also consider the flushing technology and any performance information given by the manufacturer. Avoid assuming that two toilets with similar flush volumes will perform identically.
Choose a Bowl Shape That Fits Your Room
Round bowls generally take up less front-to-back space, while elongated bowls provide a longer seating area. The Gerber is the round-bowl option here; the other listed models have elongated bowls. Measure the toilet area and check the clearance in front of the bowl, as well as the space beside it. A comfortable bowl is only useful if it fits without crowding doors, vanities, or walkways.
Think About Seat Height and Who Uses the Bathroom
Seat height affects how easy a toilet may feel to use. The HOROW lists a 17.3-inch seat height, the Casta Diva lists 17 inches, and the DeerValley lists 16 7/8 inches. The American Standard is described as standard height, and the Gerber’s seat height is not provided in the supplied details. A taller seat may be more convenient for some adults, but preferences vary, so compare the listed measurement with a toilet that feels comfortable to you.
Decide Between One-Piece and Two-Piece Construction
One-piece toilets join the tank and bowl into a single unit, creating a continuous exterior that can be easier to wipe around. Two-piece toilets have a separate tank and bowl, as seen on the Gerber and American Standard. Consider the look you prefer, the available installation space, and whether you want fewer exterior seams. Neither design should be chosen without checking dimensions and installation requirements.
Check What Comes in the Box
Included parts vary. The Gerber, HOROW, and Casta Diva list a seat, while the American Standard explicitly states that its seat is sold separately. The Casta Diva description also lists a wax seal and installation hardware. Confirm whether the package includes the seat, wax seal, bolts, and other parts you need, and check whether any special tools or additional supplies will be required.
Consider Cleaning and Routine Maintenance
Skirted sides and one-piece construction can make some exterior surfaces easier to wipe, while a two-piece toilet has a visible joint between the tank and bowl. A removable or quick-release seat can also help with cleaning around the hinges. Look at the shape of the trapway, the seat attachment, and the exterior design in relation to how you prefer to clean your bathroom.
Frequently Asked Questions
What does dual flush mean?
A dual-flush toilet gives you two flush choices, usually a lower-volume option for liquid waste and a higher-volume option for solid waste. The exact gallons per flush vary by model.
Which toilet in this comparison uses the least water per flush?
The American Standard H2Option has the lowest listed figures, at 0.92 GPF for the lower-volume flush and 1.28 GPF for the higher-volume flush. Flush volume alone does not establish overall performance, so consider the product’s other specifications as well.
Which models include a toilet seat?
The product details list a seat with the Gerber, HOROW, DeerValley, and Casta Diva toilets. The American Standard H2Option is listed without a seat, so you would need to select one separately.
Is an elongated bowl better than a round bowl?
Neither shape is best for every bathroom. An elongated bowl offers a longer seating area, while a round bowl can be useful where space is limited. Measure the available room and choose the shape that fits your space and comfort needs.
What is a toilet rough-in, and why does it matter?
The rough-in is the distance from the finished wall to the center of the drain in the floor. Matching this measurement to the toilet is important for proper fit. Measure before choosing a model, and verify any rough-in options listed for the specific version you plan to buy.
Are one-piece toilets easier to clean?
A one-piece toilet has a continuous tank-and-bowl exterior, which can mean fewer seams to wipe around. Skirted models also have smoother sides. Cleaning needs still depend on the specific shape, seat design, and bathroom setup.
Does a dual-flush toilet need a special installation?
Installation depends on the specific toilet and your bathroom’s rough-in, floor, and plumbing setup. Check the manufacturer’s instructions and package contents before starting. If you are unsure about fit or plumbing work, consider having a qualified installer handle the job.
Final Recommendation
For a compact elongated toilet with a taller seat and a choice of rough-in sizes, the HOROW T0338W is the most flexible pick in this group. Choose the American Standard H2Option if its low listed flush volumes and specified performance criteria matter most, but remember that its seat is sold separately. For a round bowl, consider the Gerber Maxwell Select; for a skirted one-piece design, compare the DeerValley and Casta Diva against your rough-in, preferred seat height, and included parts. The best choice is the one that fits your bathroom measurements and everyday comfort needs.
