As the name implies a low flow toilet uses technology that allows homemakers to save on water with every flush. It has a flushing system that is electronically timed and very efficient in performance. Best Toilets 2020 Updated May 20 Toilet Advisor Lets dive in for the details. Low flow toilet reviews . The maximum gallons per flush allowed under US federal law is 16 gallons. It is great because it allows for a second flush quickly and comes with an astonishing 15-year warranty which will definitely give you. We liked how easy this toilet is to clean with a seamless design that has nowhere to trap urine and dirt. But to be fair its got a pretty decent flush despite how little water it uses. The low-flow toilet only uses 128 GPF and has a single flush while the dual flush toilet usually has two options one of partial flush and another for a full flush. We love environmentally friendly bathrooms and low flow toilets also known as low-flush toilets or high-efficiency toilets