Let water run that you do not intend to drink.
More Mexican Proverbs:
Necessity is mother of every invention.Mexican
Do not refuse the body what it asks for.
Mexican
He who never goes to your house doesn't want you in his.
Mexican
He who knows nothing neither doubts nor fears anything.
Mexican
He who is ignorant at home is ignorant abroad.
Mexican
He who spits in the air will have it fall back on his face.
Mexican