'Fountain' in the Bible

Nevertheless a fountain or a pit wherein is a gathering of water shall be clean: but that which toucheth their carcass shall be unclean.

and he shall offer it before Jehovah, and make atonement for her; and she shall be cleansed from the fountain of her blood. This is the law for her that beareth, whether a male or a female.

And if a man shall lie with a woman having her sickness, and shall uncover her nakedness; he hath made naked her fountain, and she hath uncovered the fountain of her blood: and both of them shall be cut off from among their people.