the market price of 6 liters of European ultrafiltration water purifier is 268; Oupai ultrafiltration water purifier 1 liters market price 298. The filter element of European water purifier can generally be used for 3-5 years (depending on the local water quality). For example, a 1-liter European water purifier can generally filter 7 tons of tap water, and the cost of replacing the filter element is about 6 yuan, which is equivalent to 8 cents per ton of water. The total amount of water used in the kitchen of an average family is about .5 tons a day, that is, only 4 cents is needed to meet all the kitchen water used by the whole family for drinking water purification, cooking and soup making.