is there a problem to drink water from a sink that is in the bathroom (after taking it out of the bathroom)
Answer:
The water may be used for drinking.
Even food that has been touched before netilas yadayim in the morning, is permitted to eat post facto (Mishnah Berurah, 4:14), and although other poskim are stringent (see Kaf Hachaim 4:20), the same would apply to foods brought into a bathroom. This halachah applies to a “real bathroom,” meaning a beis hakisei of Chazal. Poskim debate whether our bathrooms are considered a beis hakisei or not, and this provides further room for leniency. Moreover, in a bathroom that includes a sink as well as a toilet, and which is used for purposes other than excusing oneself, the issue of ruach ra’ah may not apply at all, and one can use the water from the sink even on a regular basis. A similar ruling is given by Teshuvos Vehanhagos 2:4.
