Yes, our low-flows are still working great after more than two years of use in our six-person household. I installed two units made by TOTO based on performance results published by a Canadian testing organization called Veritec Consulting. Although toilet manufacturers are producing more and more toilets that flush reliably with 6 litres (even less in some cases) of water, there are still duds on the market. Veritec updates its independent performance results several times each year, making their findings available for free.
Do you still like the low-flow toilets you installed in your bathroom? I came across an old column of yours where you describe this technology and how to install it. I have two toilets in my house of unknown vintage and I’m looking to replace them.