Passive House: Water Conservation using High Efficiency Toilets (HETs)

Toto 1G Double Cyclone HET Toilet

Beyond energy conservation, we also wanted to be mindful of water conservation.

While it is true that our passive house was built on a lot that had an onsite well and septic system and hence ground water recharge, we were still concerned about conserving our water resources, especially in the event of an extended drought.

As part of our water conservation design, we chose to use high efficiency toilets (HETs) made by Toto.  We believe Toto is the global leader in design and production of HETs, offering a wide selection of WaterSense rated toilets.  The Eco Drake, Eco Drake II, Ultramax, Ultramax II toilets were our top contenders, with flush rates of 1.6 gallons per flush (GPF) to a little as 1.28 GPF. 

We considered dual flush models, however we were told that we should be prepared to explain to guests how to use them.  We ultimately decided to select Toto Ultramax II 1.28GPF one-piece toilets throughout our home.  We found Terry Love's toilet review website, most informative and trustworthy.

Toto Ultramax II 1.28gpm one piece HET Dual Cyclone Flush, Sanagloss, ADA

Some Toto models come with what Toto calls Sanagloss, an ultra-smooth slippery surface which Toto claims minimizes build-up over time.  This can be especially beneficial if one is subject to hard water (which we were).

Subsequent to our selection, Toto is now offering even higher efficiency toilets that break the 1GPF barrier.  Models include the Toto Drake II 1G.

While other manufacturers are just getting into the ultra-HET market (such as American Standard), I feel that Toto has been committed to HETs for longer than any other manufacturer and this is evident in their product maturity.

All of our toilets conform to ADA standards to allow for "age-in-place" use.