自來(lai)水(shui)(shui)(shui)在高壓(ya)密閉的(de)管道中(zhong)(zhong)輸(shu)送時,管道中(zhong)(zhong)的(de)空氣會(hui)因高壓(ya)而溶(rong)入水(shui)(shui)(shui)中(zhong)(zhong),當自來(lai)水(shui)(shui)(shui)從水(shui)(shui)(shui)龍(long)頭中(zhong)(zhong)流(liu)出時,水(shui)(shui)(shui)中(zhong)(zhong)的(de)空氣會(hui)因恢復(fu)到常壓(ya)而被釋放(fang)(fang)出來(lai),形成(cheng)無數的(de)微小氣泡,使水(shui)(shui)(shui)的(de)外觀呈乳(ru)白色,放(fang)(fang)置片刻(ke)后,即會(hui)澄清,不影響飲水(shui)(shui)(shui)衛生。