The nomenclature is that an ultralow flush toilet uses 1.6 gallons (6 liters) per flush. This is now the standard, with dualflush toilets using 3l/6l (0.8gal/1.6gal) to do their respective things. I recently read that urinals can use as little as 1 liter per flush.
We plan to renovate our bathrooms this summer, so I'm looking for watersaving devices before Dad-in-law goes and buys whatever is cheapest (and not very eco). I can't find anything on the Polish Internet, and all toilets in the store are either 3/6 liter duals, or 6 liter stop-on-demand. My Grandma has the latter and they don't always stop when they should, so I'm wary of those. The thing is that 6 liter models don't always finish their task in one flush. On the other hand, I noticed years ago that filling a bucket with 4-5 liters of water and quickly pouring it into the toilet works better than regular flushing with 6l. This may be because the water in the bucket method goes directly and doesn't lose energy in the nooks and crannies of a bowl's plumbing.
This brings up two questions:
- Can this be improved on? Are there toilets on the market that use less than 6 liters (1.6 gallons) per "big flush"?
- Can a regular toilet be made to use less than 3 liters (0.8 gallons) per "small flush"?
Putting a bottle in the reservoir to reduce its volume works well in large tanks, but not much in the 6l models. I tried reducing the volume by 0.5 liters, but that seemed to mess up the flushing mechanism (even though it didn't touch anything). Maybe it was just that individual model's fault.