Toto Aquia IV Toilet One-Piece...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$896.79
Toto Aquia IV Toilet One-Piece Toilets

Toto Aquia IV Toilet One-Piece Toilets

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Model: CST646CEMFGNAT40#01
From the Aquia IV Collection
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$896.79
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The TOTO T40 Aquia IV One-Piece Elongated Dual Flush 1.28 and 0.9 GPF Universal Height WASHLET®+ and Auto Flush Ready Toilet with CEFIONTECT® is the epitome of modern form and function. The skirted design conceals the trapway, which enhances the elegant look of the toilet and adds an additional level of sophistication. The one-piece design is not only aesthetically pleasing, but also offers the benefit of being easier to clean versus a two-piece toilet. By removing the gap between the tank and bowl, we eliminate the hiding place for dirt and debris. An additional benefit of the one-piece toilet is that there is no threat of leaks from bolts or gaskets that can occur in two-piece toilets. The Aquia IV features TOTO’s DYNAMAX TORNADO FLUSH®, utilizing a 360 degree cleaning power to reach every part of the bowl. This version of the Aquia IV includes CEFIONTECT technology, a layer of ceramic glaze that minimizes waste from sticking to ceramic surfaces. This feature, coupled with DYNAMAX TORNADO FLUSH, helps to reduce the frequency of toilet cleanings, minimizing the usage of water, harsh chemicals, and time required for cleaning. The enhanced design of the Aquia IV inner bowl reduces water flow resistance and turbulence, resulting in a quieter flush. The chrome center-mounted push button that sits atop the tank allows you to proactively conserve water by choosing between a 0.9 GPF rinse or 1.28 GPF for tougher jobs. This version of the Aquia IV offers TOTO T40 WASHLET+ and Auto Flush compatibility for when you are ready to upgrade. WASHLET+ toilets feature a channel on the bowl surface to help conceal your WASHLET+ supply line and power cord for seamless integration. The Universal Height design allows for a more comfortable seat position across a wide range of users. The TOTO Aquia IV meets the standards for EPA WaterSense®, and California’s CEC and CALGreen requirements. The Aquia IV comes ready for install into a 12" rough-in, but may be adapted for a 10" or 14" rough-in with the purchase of a separately sold adapter. Does not include seat or WASHLET. Additional items needed for installation and use must be purchased separately: compatible WASHLET or seat, wax ring, toilet mounting bolts, and water supply lines.

Features

  • DYNAMAX TORNADO FLUSH utilizes 360 degree cleaning power to reach every part of the bowl.
  • Highly efficient dual flush system promotes water conservation.
  • CEFIONTECT ceramic glaze minimizes waste from adhering to ceramic surfaces.
  • Bowl design reduces water flow resistance and turbulence, resulting in a quieter flush.
  • Completely skirted design for a sleek and understated look.
  • Elongated one-piece toilet, easier to maintain versus a two-piece toilet.
  • TOTO WASHLET+ upgrade compatibility: designed to work with a T40 WASHLET+ bidet seat for seamless integration.
  • Lid-top chrome dual flush push button - Select 1.28 or 0.9 GPF.
  • Universal Height allows for more comfort across a broader range of individuals.
  • WaterSense®, CALGreen, and CEC compliant.
  • Does not include toilet seat or WASHLET.
  • 12" Rough-in.
  • May be adapted for 10" or 14" rough-in with optional TOTO parts: TSU48.10 or TSU48.14 (sold separately).
  • Included parts: tank to bowl gasket, tank to bowl hardware, and toilet bolt caps.
  • Purchase Separately: Wax ring, toilet mounting bolts, water supply lines, T40 WASHLET+ bidet seat or compatible. toilet seat SS124 or SS234, and optional Auto Flush kit.

Manufacturer Resources

CST646F-Spec-Sheet

Product Specs

ADA Compliant:
No
CALGreen:
Yes
CEC:
Yes
Flush Valve Size:
2.5
Flush lever Location:
Center
Rim Height:
16.125
Rough-In:
12
Trapway Diameter:
2.5
WaterSense:
Yes
Collection:
Aquia IV
Product Type:
One-Piece Toilets
Product Group:
Washroom/Bath
Product Subgroup:
Toilet
Product Length:
27.625
Gallons Per Flush (GPF):
1.28|0.9
Installation Category:
Floor Mount/Floor Outlet
Product Shape:
Elongated
Product Height:
28.375
Product Category:
One-Piece Toilets
Product Weight:
118
Product Width:
15.1875
Department:
Plumbing

TOTO CST646CEMFGNAT40#01 – Frequently Asked Questions

1) Will the TOTO Aquia IV CST646CEMFG fit a 12 inch rough-in, and what if my drain is at 10 or 14 inches?
The Aquia IV one-piece ships set up for a 12 inch rough-in. If the waste line in your floor sits at 10 or 14 inches, TOTO makes adapters for it: the TSU48.10 for a 10 inch rough and the TSU48.14 for a 14 inch rough. Both are sold separately, so measure from the finished wall to the center of the closet flange before ordering. It's a floor mount, floor outlet toilet, so the flange has to be in the floor, not the wall.
2) Does the Toto Aquia IV one-piece toilet come with a seat?
No seat and no WASHLET are in the box. The Aquia IV CST646CEMFG ships with the tank to bowl gasket, tank to bowl hardware, and bolt caps only. To finish the job you need a wax ring, toilet mounting bolts, and water supply lines, plus a seat: either a T40 WASHLET+ bidet seat, or a standard SS124 or SS234 seat. An Auto Flush kit is optional. Budget those into the order or the toilet sits on the floor unusable.
3) Is the Toto Aquia IV ADA compliant for a commercial or accessible restroom?
No. The Aquia IV CST646CEMFG is not ADA compliant. Its rim height is 16-1/8 inches, which is TOTO's Universal Height and comfortable for most adults, but it falls under the 17 to 19 inch seat height an accessible fixture needs once a seat is added. For an ADA stall in a healthcare, education, or government facility, spec a TOTO model listed as ADA compliant instead. For standard guest rooms, apartments, and offices this height is fine.
4) Does the Toto Aquia IV meet WaterSense and California water efficiency rules?
Yes on all three. The Aquia IV CST646CEMFG is WaterSense labeled and meets California CEC and CALGreen requirements, which is what you need for a permit on a California new build or remodel. The dual flush button gives 0.9 GPF for liquid and 1.28 GPF for solids, so the effective flush rate stays under the state cap. That also makes it eligible where a utility or municipality requires WaterSense fixtures on a rebate or spec.
5) Should I buy a one-piece toilet like the Aquia IV or a two-piece for a rental property?
The one-piece Aquia IV has no tank to bowl joint, so there are no bolts or gasket to weep years down the line, which is the single most common slow leak in a two-piece unit. It's also faster to wipe down because there's no gap between tank and bowl and the skirted design covers the trapway. The tradeoff is handling: it's one 118 pound china fixture, so it's a two-person set, and if the china cracks you replace the whole thing rather than just a tank. For a fleet of units where callbacks cost more than the fixture, the one-piece usually wins.
6) Can I add a bidet seat to the Toto Aquia IV later?
Yes, and it's built for it. The CST646CEMFG is WASHLET+ and Auto Flush ready: the bowl has a channel molded into the surface that hides the WASHLET+ supply line and power cord, so the install looks finished rather than having a hose and cord running down the side. It takes a T40 WASHLET+ seat. Plan for a GFCI receptacle within reach of the toilet if you're roughing in a bathroom now and adding the seat later. An Auto Flush kit is also available separately.
7) How wide is the trapway on the Toto Aquia IV, and will it clog?
The trapway measures 2.5 inches, fed by a 2.5 inch flush valve. That's a full size passage paired with TOTO's DYNAMAX TORNADO FLUSH, which pushes water around the bowl in a 360 degree pattern instead of down a rim channel. The bowl also carries the CEFIONTECT glaze, a ceramic layer that keeps waste from sticking, so less material stays behind to build up. On the 0.9 GPF setting you're flushing liquid only; use the 1.28 GPF side of the button for solids.
8) Where is the flush button on the Toto Aquia IV, and is it a lever or a button?
It's a push button, chrome, mounted in the center of the tank lid rather than a side lever. Press one side for 0.9 GPF, the other for 1.28 GPF. Worth knowing on a retrofit: the tank sits under a window sill or an overhead cabinet in a lot of older baths, and a lid-top button needs clearance above the tank to press, where a side lever does not. Tank height is 28-3/8 inches overall.
9) What color does the Toto Aquia IV CST646CEMFG come in?
Cotton White, TOTO's #01 finish, is the only color for this model, ordered as CST646CEMFGNAT40#01. If you're matching an existing lav or tub in a bathroom refit, Cotton White is TOTO's standard bright white and pairs with the rest of their #01 fixtures. It will not match Colonial White or Sedona Beige, so check the code stamped under the tank lid of what's already in the room before you standardize a building on it.
How fast can I get the TOTO CST646CEMFGNAT40#01 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the TOTO CST646CEMFGNAT40#01 come with a warranty?
Absolutely. The TOTO CST646CEMFGNAT40#01 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the TOTO CST646CEMFGNAT40#01?
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