1) Water which is so bitter, rotten or salty that a dog is unable to drink it (e.g. seawater), is unfit for washing one’s hands. It is, however, fit for immersing one’s hands. (If one distilled the water or changed it in any other way whereby it becomes fit for a dog one may use them for washing one’s hands.) (Shulchan Aruch and Mishne Berura 160)
2) Water which is opaque because it has been mixed with mud, if it has not become too thick for a dog to drink, remains fit for washing one’s hands. If it has become too thick for a dog to drink, it is unfit even for immersing one’s hands. (ibid)
