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Toilet Comparison

TOTO Aquia IV Dual Flush Two-Piece Toilet vs American Standard H2Option Dual Flush Toilet: Which Should You Buy?

Side-by-side spec comparison, flush power data and real owner feedback.

Winner for most people

TOTO Aquia IV Dual Flush Two-Piece Toilet

The TOTO Aquia IV wins decisively with a MaP score of 1000g, nearly double the H2Option's 600g, plus a 3-inch trapway and CEFIONTECT glaze for superior waste handling and cleanliness.

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SpecTOTO Aquia IVH2Option
MaP Score1000g600g
GPF1.28 / 0.81.28 / 0.92
Flush SystemTORNADO FLUSH dualDual flush siphon
Trapway3-inch fully glazed2.375-inch fully glazed
HeightUniversal height (17 in)Chair height (16.5 in)
Rough-In12-inch12-inch
Seat IncludedNoYes
WaterSenseYesYes
Warranty1 yearLimited lifetime
Overall Edge→ TOTO Aquia IV for superior flush power and cleaning technology

TOTO Aquia IV Dual Flush Two-Piece Toilet

MaP Score1000g
GPF1.28 / 0.8
FlushTORNADO FLUSH
Trapway3-inch
SeatNot included

Pros

  • MaP score of 1000g handles heavy waste with ease
  • TORNADO FLUSH uses dual nozzles for powerful, clog-free performance
  • CEFIONTECT glaze prevents debris from sticking
  • 3-inch fully glazed trapway reduces blockages

Cons

  • Seat not included, adding to initial cost
  • Warranty is only 1 year, shorter than some competitors
  • Universal height may be too tall for shorter users

The TOTO Aquia IV is a dual flush two-piece toilet designed for maximum flush efficiency. Its TORNADO FLUSH system uses two powerful nozzles to create a centrifugal rinse that cleans the bowl thoroughly with each flush. The MaP score of 1000g means it can clear up to 1000 grams of solid waste in a single flush, making it one of the most powerful dual flush options on the market. The 3-inch fully glazed trapway further ensures that waste passes through smoothly without getting stuck.

CEFIONTECT glaze is a key feature that sets this toilet apart. It creates a smooth, ionized barrier that prevents waste and bacteria from adhering to the ceramic surface. This means less frequent cleaning and better hygiene over time. While the seat is not included and the warranty is limited to one year, the flush performance and build quality make it a top choice for homeowners who prioritize reliability and power.

Expert Take

The TOTO Aquia IV offers the best dual flush performance in its class, with a MaP score that exceeds most competitors and a trapway that minimizes clogs.

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American Standard H2Option Dual Flush Toilet

MaP Score600g
GPF1.28 / 0.92
FlushDual flush siphon
Trapway2.375-inch
SeatIncluded

Pros

  • Seat included, saving on accessories
  • Limited lifetime warranty offers long-term peace of mind
  • Chair height (16.5 in) is comfortable for most adults
  • WaterSense certified for water savings

Cons

  • MaP score of 600g is low for heavy waste
  • 2.375-inch trapway is narrower, increasing clog risk
  • No CEFIONTECT or similar anti-stick glaze
  • Higher liquid flush uses 0.92 GPF vs TOTO's 0.8 GPF

The American Standard H2Option is a dual flush toilet that focuses on affordability and convenience. It comes with a seat included, which reduces the total cost of ownership, and a limited lifetime warranty that covers the toilet for many years. The chair height of 16.5 inches is close to standard chair height, making it accessible for most users. It is also WaterSense certified, meaning it meets EPA standards for water efficiency.

However, the H2Option falls short in flush performance. Its MaP score of 600g is significantly lower than the TOTO Aquia IV's 1000g, meaning it may struggle with larger waste loads. The trapway is only 2.375 inches, which is narrower and more prone to clogs. Additionally, the liquid flush uses 0.92 GPF, which is less efficient than the TOTO's 0.8 GPF. Without an anti-stick glaze, the bowl may require more frequent cleaning. It is a decent budget option but not ideal for high-performance needs.

Expert Take

The H2Option is a solid entry-level dual flush toilet, but its lower MaP score and narrower trapway make it less suitable for households with heavy use.

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Which has better flush power?

The TOTO Aquia IV has significantly better flush power. Its MaP score of 1000g means it can clear up to 1000 grams of solid waste in a single flush, while the American Standard H2Option only manages 600g. The MaP (Maximum Performance) score is an industry standard test that measures how much waste a toilet can flush effectively. A score of 1000g is considered excellent and suitable for heavy use, while 600g is below average and may lead to double flushing with larger loads. The TOTO also uses a 3-inch trapway compared to the H2Option's 2.375-inch trapway, which further reduces clog risk.

Which saves more water?

Both toilets are WaterSense certified, but the TOTO Aquia IV saves more water on the liquid flush. The TOTO uses 1.28 GPF for solid waste and 0.8 GPF for liquid waste, while the H2Option uses 1.28 GPF for solid and 0.92 GPF for liquid. The TOTO's liquid flush uses 0.12 gallons less per flush, which can add up to significant savings over time. For solid waste, both use the same 1.28 GPF. The TOTO's lower liquid flush rate makes it the more water-efficient choice overall, especially in households with frequent liquid flushes.

Which is better for heavy waste?

The TOTO Aquia IV is clearly better for heavy waste. Its MaP score of 1000g is nearly double the H2Option's 600g, meaning it can handle much larger waste loads without clogging. The 3-inch trapway is wider and fully glazed, allowing waste to pass through more easily. The TORNADO FLUSH system also helps by using dual nozzles to create a powerful rinsing action that clears the bowl thoroughly. For households with heavy waste, the TOTO Aquia IV is the superior choice, while the H2Option may require double flushing or cause blockages.

Choose TOTO Aquia IV if...

  • You need maximum flush power for heavy waste
  • You want a wider 3-inch trapway to prevent clogs
  • You prefer CEFIONTECT glaze for easier cleaning
  • You want the most water-efficient liquid flush at 0.8 GPF

Choose H2Option if...

  • You want a seat included to save on accessories
  • You value a limited lifetime warranty for long-term coverage
  • You have a tight budget and need a basic dual flush toilet
  • You prefer a chair height close to standard seating

Frequently Asked Questions

What does MaP score mean?

MaP stands for Maximum Performance. It measures how many grams of solid waste a toilet can flush in a single test. A score of 1000g means it can handle 1000 grams, while 600g handles 600 grams. Higher scores indicate better flush power.

Is the TOTO Aquia IV seat included?

No, the TOTO Aquia IV does not come with a seat. You need to purchase a compatible seat separately. The American Standard H2Option includes a seat.

Which toilet has a better warranty?

The American Standard H2Option has a limited lifetime warranty, while the TOTO Aquia IV has a 1-year warranty. The H2Option offers better long-term coverage.

Are both toilets WaterSense certified?

Yes, both the TOTO Aquia IV and the American Standard H2Option are WaterSense certified, meaning they meet EPA standards for water efficiency.

What is the difference in trapway size?

The TOTO Aquia IV has a 3-inch fully glazed trapway, while the H2Option has a 2.375-inch fully glazed trapway. A larger trapway reduces clog risk.

Which toilet is taller?

The TOTO Aquia IV has a universal height of 17 inches, while the H2Option has a chair height of 16.5 inches. The TOTO is slightly taller.

Does the H2Option have CEFIONTECT?

No, the American Standard H2Option does not have CEFIONTECT or any similar anti-stick glaze. The TOTO Aquia IV features CEFIONTECT for easier cleaning.

Which toilet is better for a large family?

The TOTO Aquia IV is better for a large family due to its higher MaP score, wider trapway, and more efficient liquid flush. It handles heavy use more reliably.

Sources

  • MaP Flush Testing Program, map-testing.com
  • EPA WaterSense, epa.gov/watersense
  • Manufacturer published specifications

Verdict

The TOTO Aquia IV Dual Flush Two-Piece Toilet is the clear winner for most buyers, offering superior flush power with a MaP score of 1000g, a 3-inch trapway, and CEFIONTECT glaze. The American Standard H2Option is a budget-friendly alternative with a seat included and a lifetime warranty, but its 600g MaP score and narrower trapway make it less capable for heavy waste.

How we rank & our data sources

We do not run physical lab tests. Rankings are built from published, verifiable data and real owner feedback, never paid placement.

Researched by BFT Editorial Team · Last updated June 30, 2026 · Our review method

B
Researched by BFT Editorial Team

The Best Flushing Toilets editorial team researches MaP flush scores, water efficiency data, and owner feedback to help you find the right toilet.

Updated June 2026 · Comparisons
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