The commonly used technologies in China are: PP filtration+activated carbon filtration +PP filtration+reverse osmosis +UF+ terminal activated carbon filtration. This kind of effluent can be drunk directly, which is sweet and delicious. I have measured the conductivity of the effluent about 30us/cm, which is better than the bottled purified water I bought. Cooking with it is very mellow.
The famous brand filter screen in big shopping malls has a beautiful appearance, but the price is thousands, and the water outlet effect is the same as above.
It is suggested to buy more from Taobao in 500 yuan, which is economical and practical. I installed it on the wall near the toilet. When making water, there is reverse osmosis concentrated water, which just goes to the toilet tank for flushing.