Top Toilets with Largest Trapway Sizes: No more Clogs!

Toilets can be designed in all kinds of ways, whether it’s a high flow, low flow, one-piece, or two-piece. Toilets with large trap ways provide more space for waste to pass through, hence the term no-clog toilets.

These toilets have outlets as big as three inches in diameter, bigger than the industry size of two inches. They aim to offer a bigger path for waste to drain into the sewer without clogging or leaving waste behind. Some of the best toilets with large trapways include the American Standard Champion, Woodbridge, American Standard Cadet, Toto Drake Ultramax, Toto Promenade, among others.

What they have in common is their large-diameter trapway plus a powerful flush that allows them to carry away even the largest of waste. They’re unlikely to get clogged or have multiple other toilet issues. Below is a detailed look at these toilets, with a guide on features to look for.

American Standard Champion 4 2034.314.020

First in line is the American Standard Champion 4, which excels as the best performing toilet.

It has the industry’s largest siphonic trapway and biggest flush valve. With the huge trapway along with the flushing power, you’re sure to get your money’s worth.

American Standard Champion 4


  • A two ⅜ inch(2.375 inches) fully glazed trapway – this means it can handle very bulk waste, more than your average toilet.
  • 4-inch piston action, accelerator flush valve
  • One-piece ADA toilet that saves on space and maintains industry regulations.
  • Elongated – adds more comfort when you sit to do your thing. 
  • Siphon action jetted bowl – releases more water for a powerful flush.
  • Slow close toilet seat – minimal on the noise, easy to maintain, and safer for the household.
  • Ever clean surface for a cleaner appearance
  • Low-consumption (6.0 Lpf/1.6 GPF) helps you save water
  • Four-inch piston action Accelerator flush valve with a twelve-inch rough-in.


  • Maintains a clean towel bowl with its large flush valve, siphonic action bowl with jets, and antimicrobial, EverClean glaze.
  • Compact to safeguard on space
  • ADA compliant with a height of 19 inches.
  • Comfortable thanks to its elongated bowl shape.
  • Comes in multiple colors to suit your needs. White, linen, and bone with a Vitreous China coat.
  • Safer to handle with the soft close toilet seat.


  • Not good at conserving water with its 1.6 GPF rate.
  • Heavy weighing over 100 pounds
  • Noisy when refilling water.

Toto MS854114SL #01 Ultramax Elongated Toilet

Yet another one-piece toilet is the Toto Ultramax made with a Vitreous China coating. It only weighs 89 pounds, unlike the upper choice.

Toto MS854114SL


  • Four available colors – cotton, colonial white, bone, and Sedona beige.
  • It has a three-inch flush valve and a two and an eighth inch fully glazed trapway that’s surely meant to flush away very bulky waste without clogging.
  • Elongated open front shape
  • It has a bowl rim height of 16.5 inches for added comfort
  • A water consumption rate of just 1.6 gallons per flush
  • 17-inch comfort height to give space for your legs.
  • Gravity flush toilet with a G-max flushing system that delivers a powerful flush, thanks to the large 3-inch flush valve
  • Floor mounted hence better stability
  • WaterSense certified to ensure proper usage of water
  • Molded bumper
  • High Gloss Polypropylene that’s resistant to chemicals and cleaning agents.


  • Durable
  • It can easily fit compact spaces as it’s one piece and elongated.
  • Has a one-year limited warranty
  • Low water usage
  • ADA  compliant
  • Soft close toilet seat
  • Comfortable ergonomic design
  • Quiet


  • Water consumption could be better.

WoodBridge T-0001 One Piece: Non-Clogging Skirted Toilet with Dual Flush

The WoodBridge T-0001 one-piece toilet is not only known for its dual flush non-clogging abilities but also its rectangular shape/ D shaped toilet that’s unique compared to the others.

WoodBridge T-0001


  • Elongated, comfort height, one-piece toilet
  • It has a dual Flush System Design: 1. 0 /1. 6 GPF, average at 1. 28 gallons per flush, and Siphon Flushing Design
  • A fully glazed flush system that’s quiet and powerful.
  • Easy-to-Clean Design – The skirted trapway creates a sleek look and makes cleaning easier
  • High-end soft closing seat with stainless steel durable seat hinges attached to the all in one package.
  • All-in-One Package Design: Includes toilet, pre-installed soft closing toilet seat, high-quality wax ring, floor bolts, and installation instruction High-end Soft Closing Seat with Stainless Steel Durable Seat Hinge
  • Certified as high-efficiency by WaterSense and US & Canada UPC & CSA certification.


  • Easy to clean
  • Super quiet
  • Powerful flushing system
  • High-quality soft closing seat
  • Luxurious look with a ceramic finish
  • Five-year guarantee


  • Height is taller than usual which can be an issue for kids
  • Available in just two colors
  • Heavy weighing 119 pounds

TOTO CST744SR#01 Drake 2-Piece Trapway Toilet

The CST744SR#01 Drake is yet another Toto elongated toilet that comes as a two-piece toilet. This particular toilet is uniquely known for its CEFIONTECT glaze that offers a classic high-profile design that’s powerful and durable enough to work within both residential and commercial applications.

TOTO CST744SR#01 Drake
CST744SR#01 Drake


  • Has a G-Max flushing system that works hand in hand with the three-inch flushing valve to take away bulky waste and ensure no clogging or leaks.
  • It has an extra-large siphon jet and a large trapway for maximum performance
  • Powerful flush with a water consumption of 1.6 gallons per flush.
  • SoftClose seat with an upgraded electronic washlet bidet seat
  • Large water surface area for easy cleaning
  • CEFIONTECT ceramic glaze offers a smooth and cleaner finish.
  • It has an ionic barrier to protect the ceramic coating from harsh chemicals.


  • Easy to clean
  • Powerful flushing system
  • Assorted color variations
  • One year warranty
  • Elongated toilet for additional comfort.


  • Not ADA compliant
  • The sanagloss effect in the bowl easily fades leaving marks and lining in the bowl.

Kohler K-3493-0 Highline Classic Pressure Lite

The list would be incomplete without a Kohler. The Kohler K-3493-0 Highline toilet has all the great features you would want. From a comfort height, elongated bowl, pressure-assisted flush, plus much more.

Kohler K-3493-0 Highline
Kohler K-3493-0


  • Elongated, two piece toilet with a comfort height of 17 inches.
  • Pressure assisted flush with a water usage of 1.4 – 1.6 gallons per flush
  • A contemporary look with a Vitreous China coating material
  • Has a left-hand hand trip lever
  • Three-inch flush valve to minimize clogs and leaves the toilet looking clean.


  • Good chair height
  • Easy to clean
  • Powerful flush
  • Good water consumption


  • The trip lever design is quite faulty
  • Not an all-inclusive package as it doesn’t come with a wax ring

TOTO Promenade II Universal Height Clog-Free Toilet

The TOTO Promenade II is an equally beautiful one-piece toilet with great water usage of just 1.28 gallons per flush and a beautiful cefiontect finish making it easier to clean.

TOTO Promenade II
TOTO Promenade II


  • A one-piece toilet with no gaping between the tank and bowl, therefore eliminating dirt, debris, and leakage that may occur.
  • A tornado flush for minimized washing frequency and water usage
  • Hole free rim design with dual-nozzles for a centrifugal washing action, keeping the toilet cleaner for longer.
  • Cefiontect glaze for a smooth finish and reduction of adhering of particles in the ceramic toilet
  • Universal 17.25 inch height toilet for a range of users including ADA compliance.
  • Meets the EPA WaterSense. CEC, and calgreen requirements.
  • It has a left-hand chrome trip lever
  • It has a soft close seat.


  • Easy to clean
  • Water-efficient flushing system
  • Comes in an array of colors
  • ADA compliant
  • Certified as a high-quality toilet
  • Safer with the soft close toilet seat


  • Noisy

American Standard Cadet 3 FloWise Concealed Trapway 2-Piece Toilet

Lastly, the American Standard Cadet 2988101.020 , that’s a two-piece toilet, compact, and space-saving. It has a MaP score of 1000 grams, hence unlikely to clog as it can move really bulky masses down the toilet.

American Standard Cadet 3 FloWise
Cadet 3 FloWise


  • Made of strong and durable Vitreous China coating
  • Comfort height that can be used by anyone
  • Pressure-assisted siphon jet flush action with a fully glazed 2-1/8″ trapway
  • Has a Cadet three flushing system that’s not only powerful but quiet.
  • Excellent water consumption of 1.28 gallons per flush
  • Has a skirted design and for an EverClean surface – the skirted design makes cleaning outside easy, while the EverClean surface prevents
  • EPA Certified by WaterSense
  • Floor mounted for stability
  • Soft close seat


  • Has a five-year warranty
  • Easy to clean
  • Sturdy and durable
  • Excellent flushing system
  • Good water consumption
  • Lighter than the other toilets weighing just 75 pounds
  • Varied flow rates to choose from – 1.6, 1.28, and 1.1 gallons per flush
  • Antibacterial and antiviral EverClean surface


  • Very loud
  • Not many colors to choose from

Buying Guide

Buying the right toilet can save you a bunch of repairs and maintenance fees for calling a plumber. So here’s a guide in how you. Can buy the best high flow no clog toilet.

Toilet Trapway
Toto toilet Trapway

What is a Toilet Trapway?

A toilet trapway is the section through which water and waste quit the bowl heading to your sewer system. The trapway is also referred to as an outlet or siphon outlet.

It is a curved, mostly S-shaped, pipe behind the bowl that links the toilet’s drain in the bowl’s bottom to the closet flange on the floor.

The s-shape allows the trapway to hold water between flushes, providing a seal against sewer gases entering through the toilet bowl. It also creates a siphonic effect that helps in the flushing process.Toilet

Trapway sizes range from the industry-standard 2-inch diameter up to the industry-leading 2-3/8-inch diameter. The minimum trapway size that is allowed by ANSI (American National Standards Institute) is 1 1/2 inches but most toilets usually have a trapway between 1 3/4 to 2 inches.

The largest trapway toilet has a diameter of 2-3/8-inches and a flush valve measuring 4 inches. It is the champion collection manufactured by the American Standard.

Larger trapways combined with large flush valves provide the best flush performance regardless of the type of matter you’re flushing out.

Concealed Trapway Toilet vs Skirted Trapway

Concealed and skirted trapway toilets both have their siphon outlets covered up. You cannot see the curved siphon tube behind the bowl. This design not only makes it easier to clean the toilet but also improves the look of the toilet.

Although the terms are sometimes used for each other, skirted and concealed differ especially, in how they are designed.  The concealed design has a smooth surface at the back that basically covers the trapway, leaving the bowl to flare out while the skirted design has a smooth, sleek line from front to back, and from the top of the tank to the floor, making it easy to clean.

The following are more factors/features to look for when shopping for high-flow toilets.

High Efficiency

High efficiency toilets maximize performance and reduce any waste and costs incurred. Therefore, you’re looking for toilets that can save your gallons of water and still give you a better flushing power than standard or low-flow models.

Flush Rating and Power

The next feature to look at is the flush rating and power. To start, large trap ways have the best performance since they come with a slightly bigger diameter than the standard of two inches. It could be 2 ⅜ up to three inches wide to offer more passageway for the waste.

Larger toilet trapways are better

The opening valve could also be higher up to four inches. This is great as the larger the opening, the better the performance, hence little to no chances of clogging.

Other brands such as the American Standard will have something called the bulk removal ratings which aids you to choose the type of trap way you want. These have the best compared to other types of toilets.

Another way to gauge the toilet is by looking at the MaP ratings. These are ratings from manufacturers who score a toilet one on a 0-1000 gram scale.

They get this score by using material designed to replace and act similarly to the average-sized human waste, and seeing how the mechanism handles it. The results are often unbiased and build on each model’s capabilities.

Water Consumption and Usage

If you’re looking to save on water consumption, then you have to look at the water usage from the toilet. This is the GPF rating on the toilet read as gallons per flush.

This allows consumers to know how much water is utilized in every flush. 1.6 gallons per flush is more prevalent than 1.28 or 1.1, however, 1.28 is gaining traction as it meets the EPA guidelines that safeguard water usage.

Efficiency also depends on the type of flushing system and mechanism. The following are the most common;

  • Gravity – very common in the market, it simply uses gravity to create pressure that uses the water/ water into the trapway to the sewer line. They’re easy to maintain, but work best with low-flow toilets. Hence, this isn’t the best option for a high efficiency toilet.
  • Pressure assisted is much louder but has more air that increases the flushing power. Recent models like the Kohler K-3493-0, use the pressure assisted model for a stronger high flow, less water flush. Moreover, they work similarly to dual flush systems which are the best for high efficiency.
  • Double cyclone – this is the use of both pressure and gravity to achieve a more powerful flush with less water. The Toto brand is well known to use this system in their toilets as it can easily utilize a 1.28 GPF to achieve better results than the 1.6 GPF. To identify this system, some brands will use the name double nozzles.
  • Dual flush – this is the best choice for high efficiency as it offers two flushing options such as 1.1 gallons or 1.6 gallons, and can be quiet.


How clean the toilet is left is also a major concern as this means the water circulates and reaches every corner of the toilet leaving it clean.

Check for added glaze such as CEFIONTECT, which is a nanoscale. It means it’s an ionized protective barrier that will coat the ceramic for a smoother finish and protects the toilet from harsh chemicals and cleaning agents that may damage it.

This also adds to hygiene as the coating will prevent the adherence of dirt, debris, and particles that may leave bacteria to build up in the toilet. Other brands will also have a sanagloss glaze or just a smooth finish.


These are other things you may look for as you shop for the toilet.


Check for a comfort height toilet that follows ADA guidelines such as the seat should be 17 to 19 inches high from the ground.

This allows you to comfortably rest your feet on the ground. The height is taller than the standard of 16 inches, but it suits a wide variety of customers.

More dimensions you may look for are the bowl length to check if it’s elongated, or the tank and toilet height.

Another measurement is the rough-in size that’s often at 12 inches but you could find some options in 10 and 14-inch models.


Aesthetics is also a vital element to look for. You may prefer one or two-piece toilets, therefore you should have a choice. Two-piece tend to be more expensive, heavy and could breed spaces for bacteria from the dirt and debris that accumulates between the tank and toilet.

The different toilets also have different designs as you have noted the WoodBridge has a rectangular shape compared to the Kohler and Toto Drake with an oval elongated design. Others can also be round, open front, or in other shapes.

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