To obtain an adsorbent persistent water repellent which can be used even in the presence of water and is excellent in water repellency and durability by using a specified fluoroalkylsilane, aminated polysiloxane, solvent and acid, and water as the constituents.

This water repellent contains a fluoroalkylsilane represented by the formula CF3(CF2)nCH2CH2Si(OMe)3 or the formula CF3(CF2)nCH2CH2Si(OMe)3 (wherein n is 5 to 8; and Me is CH3 or C2H5), preferably in an amount of 0.001-5wt.%, an aminated polysiloxane represented by the formula [where R is CH3 or C2H5; j is 0 to 3, and j+k=(0 to 3); and m and l are each such an integer of 1 or greater as to provide a viscosity at 25°C of 10-10,000cSt and an amine equivalent of 300 to 10,000], preferably in an amount of 0.001-20wt.%, a solvent comprising mainly an alcohol capable of dissolving the fluoroalkylsilane and the aminated polysiloxane, preferably in an amount of 5-99.8wt.%, a lower carboxylic acid such as formic or acetic acid, or a monobasic acid selected from mineral acids such as hydrochloric and nitric acids, preferably in an amount of 0.001-5wt.%, and water preferably in an amount of 0.1-95wt.%.