I think the idea of low volume flush toilets, 1.6 or less is a good idea for water conservation purposes but in our neck of the woods (milwaukee wisconsin) they create nothing but trouble on lake front homes built before 1960. Drainage systems were designed with low pitch 5" clay and or cast iron piping which were built for 3.5 gallon or higher flush toilets. Sure the new toilets may force the solids out of the bowl quickly and reliably but when it comes to getting the solids to the street with one, two, or three flushes on the long runs forget it. The solids, on a steady basis, build up in the pipe and cause back up problems because the new toilets just dont produce enough water to move the solids at a steady enough rate to keep the systems from backing up on occasion. Even though this produces a steady income for me, snaking out drain systems, it is a nightmare for many home owners. Old 3.5 gallon flush toilets are worth their weight in gold in this area even though they are illegal to install and I wont install them. The homeowners dont care about the cost of their water in this area compared to the cost of having me come out to unclog drain systems. Point is: low water volume may be good if you have alot of people using many toilets on the same drainage system but when it comes to older homes they can cause more problems than they are worth. When people have to flush the toilet 3 times just to keep things moving where does the water conservation factor come in? Be careful on older homes and dont be so quick to change out older 3.5 gallon flush toilets unless the homeowner is aware of the potential results. Add one tampax to the equation and the lack of forceful volume of water creates an even better income for me.