Toto Aquia CST416M Review

Updated July 31, 2015
Toto Aquia CST416M Review
Bottom Line

The Toto Aquia CST416M dual-flush toilet is worth serious consideration if you want a dual flush toilet as part of a new bathroom or to replace an existing standard (single-flush) toilet. The Toto Aquia earns some of the highest ratings we found for its performance in flushing both liquid and solid waste. It's also a fairly compact toilet for those that are short on space.

ProsCompact, WaterSense certified, Solid waste flush option cleans bowl well, Skirted design is easy to cleanConsChallenging installation, Learning curve for optimal flushing

Breaking it down


Dual flush; two piece toilet. The Toto Aquia CST416M is a two-piece, dual flush toilet with a gravity-assisted, tower-flush operation. The Aquia is WaterSense certified to reduce water consumption. It features a two-button, pushbutton flush operation, one for solid waste, the other for liquid waste. It's WaterSense certified. The pushbuttons are located on the top of the tank, rather than the traditional trip lever on the side. The toilet seat is not included, but the Aquia is compatible with a wide range of seat options.


A bit of a learning curve. The Toto Aquia's Maximum Performance (MaP) score is only 500 out of a possible 1,000, and it does not clean the bowl of solid waste as efficiently as standard, single flush toilets in professional tests. However, owners say that they love the performance of the Toto Aquia CST416M once they get the hang of how long to hold down the buttons. Unlike a traditional lever flush toilet, you can't just push and go. Users say you have to hold the solid waste button down for as much as 5 seconds to get a good, complete flush and total bowl-cleaning performance, but even then there are plenty of complaints that the Aquia does not clean the bowl of solid waste and has to be flushed a second time. However, the vast majority are pleased, especially since the solid waste option uses 1.6 gpf, but the liquid waste option only .9 gpf and water-conscious users prefer that alternative to a single flush toilet.


A challenge to install, but easy to clean. The skirted, concealed trapway design of the Toto Aquia CST416M is frequently praised by owners for being both modern-looking and easy to clean. Quite a few reviewers say the Aquia is more difficult to install than most standard toilets; but many others disagree, saying they had no issues at all. It may be worth hiring a plumber to avoid any possible issues, although Toto's customer service is reported as extremely helpful for those who have questions or problems. The Aquia CST416M has a smaller footprint than most toilets, making it an excellent choice for a smaller space. Its 15.25 inch bowl height does not meet ADA standards. The Toto Aquia CST416M comes in five colors.

Our Sources


Toto Aquia CST416M01 toilet, Editors of, Not Dated

The Toto Aquia CST416M01 (the 01 designates the color white) toilet is one of seven dual-flush toilets tested by editors of Toilets are tested on how well they handle solid waste removal, liquid waste removal and on their noise level. Each toilets is ranked and rated against others that have also been tested.

2. Maximum Performance

MaP Search - Residential Toilets (Tank Type), Editors of Maximum Performance, Not Dated

The Toto Aquia CST416M earns a MaP score of 500, which falls in the range of "Recommended" for strong flushing performance, just below the highest "Highly Recommended" rating. This score denotes the toilets ability to remove 500 grams of solid waste or more with each flush.


TOTO CST416M Aquia II Dual Flush Two Piece Toilet 1.6 GPF / 0.9 GPF, Contributors to, As of August 2015

More than 110 owners give the Toto Aquia CST416M an overall rating of 4.6 stars out of 5, saying it's very easy to clean, and that both components of the dual flush action work well. It also earns kudos for its modern, easy to clean design. A few say it's more difficult to install than a standard, two-piece, single flush toilet.


TOTO CST416M#01 Aquia II 2-Piece Toilet with Regular Height Bowl and Dual Max Tank, Cotton White, Contributors to, As of August 2015

Nearly 70 owners rate the Toto Aquia CST416M, giving it 4.4 stars out of 5. Some note that there is a learning curve to holding down each button for just the right number of seconds for a clean flush, but that once you figure it out, they say the Toto Aquia handles even larger amounts of waste very well. Some say the installation is challenging.


TOTO Aquia II 2-piece 1.6 GPF or 0.9 GPF Dual Flush Elongated Toilet in Cotton - No Seat, Contributors to, As of August 2015

The Toto Aquia CST416M earns an overall rating of 4.3 stars out of 5 at and 88 percent of owners would recommend it. The Aquia gets its highest ratings for quality and value, but lower scores for ease of installation, which many say it harder than for other, standard toilets.


Terry Love's Consumer Toilet Reports, Terry Love, May 28, 2014

The Toto Aquia CST CST416M is the top rated dual-flush toilet here, with a 4-star rating by plumber Terry Love. Details of the review are not noted, but brief comments about its water saving abilities are included. Further down the page, Love notes that he has been selling and installing a lot of Toto dual flush toilets and they have a good track record.