There are two common water purifiers in the market: ultrafiltration water purifier and reverse osmosis water purifier. Only the water filtered by the reverse osmosis water purifier can be directly drunk. Ultrafiltration water purifier has the advantages of no power consumption, no waste water, large water output and low price, but the purification effect is relatively poor, so it is best to drink it after heating. The reverse osmosis water purifier has good purification effect and high precision, and the purified water can be directly drunk, which is very healthy.