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by • January 18, 2013 • Water Heating & Plumbing & ToiletsComments (6)13597

Dual Flush vs HET Toilets – (not for the squeamish)

Ok so I’m on a toilet blogging kick lately.  Feel free to skip this post if you are squeamish about potty talk.  I’ve talked about the Toto Aquia Dual Flush toilet on my blog in the past.  I’ve probably installed 30 of these toilets in the last 6 years and they are a fantastic flushing toilet.  They use .8 gallons of water on the low flush button and 1.6 gallons on the high flush button.  This Aquia at my house is a powerhouse flusher and has not once clogged, I liked it for a while….  Except, my opinion of them (meaning all Dual Flush toilets) has changed after a few years.  Here’s why, they have a TINY water spot inside the bowl.  Here’s a photo of the Aquia in my Guest Bathroom.

It’s a nice looking modern toilet.  Dual flush buttons are on the top of the tank.
Here’s a shot of the bowl, can you see that tiny water spot?

I added some blue food color drops to show how tiny the water spot is on this dual flush toilets.

 It’s my opinion that all Dual Flush toilets suffer from this same issue of a small water spot.  I probably don’t need to spell this out, but the issue with this small spot is that when you go #2 in this toilet your target is small.  Thus, you end up streaking #2 in the toilet on dry porcelein.  The initial flush will get most of this down the drain but it leaves some clinging to the bowl which necessitates using a toilet brush to clean the bowl, then hitting the flush button again.  Your 1.6 gallon initial flush plus this second “cleaning” flush using the .8gallon button means that going #2 actually requires 2.4 gallons of water use.  Plus you’ve now got a yucky toilet brush with remnants of #2 attached.  (Sorry for the graphic nature, but this NEVER gets mentioned and I sure didn’t know it ahead of time)
  So, now let’s compare the water spot on HET (high efficiency toilets are 1.28 gallons per single flush).  Here’s my hall bathroom with a Kohler Wellworth 1.28 gpf HET. 

Kohler Wellworth HET.  Not quite as good looking as the Toto Aquia
Look at that normal water spot.  It’s HUGE compared to the Dual Flush models. 
Here’s my Toto EcoDrake HET in my Master Bath.  I’ve had it 5 years now and LOVE it.
Here’s the water spot on the Toto EcoDrake HET.

The photo above is the EcoDrake (see my review of this toilet) which uses 1.28 gallons of water, but the water spot looks like an average 1.6 GPF normal toilet.  In the end it’s this normal sized water spot that puts these HET toilets on my recommended list.  I no longer recommend Dual Flush toilets and I would be sure you know what you are getting into before buying one.

HET vs Dual Flush =  HET Wins!

Sorry for the gross post, but it had to be done…
-Matt Risinger
Risinger Homes in Austin TX 

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  • Have you heard of the 0.8 GPF Stealth UHET, also sold as Proficiency? We’ve had pretty good experience with it: http://farwellmanor.blogspot.com/2012/03/day-85-our-humble-commode.html Not perfect on the streaking front but much better than a minuscule water spot!

    • Thanks for commenting. I’m about to install my first Stealth so I’m excited to see it. I’ve got a client who wanted one for all three bathrooms of their house. Best, Matt

  • Blesk

    Thank you much for this article. I was doing research on the differences between HET’s and dual flush models to make sure I did not make a decision I would grow to regret, but I must say the water spot footprint was not something I even considered nor something that is mentioned anywhere on the toilet specs.

  • Justin Rich

    From what i’ve read of dual flush toilets they all seem to advertise some special coatings (everclean) that is so smooth they promise not to have this problem. With this article being ‘old’ and one of the few good comparisons, do you think this matters, has your opinion changed since?

    • Old article, but it’s still applicable today. I would write this again today with the same opinion. Matt

  • pfwag

    Great post. If you want independent toilet performance ratings and how much #2 they will flush using how much water, go to:
    http://www.map-testing.com/
    Stick with the PREMIUM rated toilets – which does not necessarily mean more expensive.