Reverse osmosis water purifier standard wastewater ratio is theoretically 1:3 (good water: wastewater). Anything that passes through the reverse osmosis membrane has to be discharged as wastewater.
There are two options for saving water:
1. Collect wastewater, wash dishes, mop the floor, flush the toilet.
2. Add an ultrafiltration membrane before the reverse osmosis membrane (equivalent to coarse filtration, to improve the quality of the source water), and then adjust the wastewater ratio smaller. This can also achieve the purpose of saving water.
The ratio of wastewater and pure water does not have a certain, or even can do zero discharge reverse osmosis equipment system, but relatively high cost, reverse osmosis system service life will certainly not be very long, so it is generally not necessary to do.