Tosefta zu Terumot 8:5

Started dough that was kneaded in exposed water -- even if it [the dough] was of terumah, you must burn it, and it goes without saying that chullin [started dough must also be burned]. Rabbi Nechemiah says, if it was baked, behold, it is permitted because snake poison is destroyed in fire.

The water from pickling [terumah], the water from stewing [terumah], the water of [cooked] peas -- they are not subject to the [prohibition against consuming] exposed liquids. The water in which there remains inside it [pieces of] pickles, stew, or peas, if there is [sufficient quantity] in them to impart taste, they are permitted, and if not, they are forbidden. Water in which quince or Damascene plums were rinsed [as a remedy for] a sick person -- they are not subject to the [prohibition against consuming] exposed liquids. Water that was exposed and then heated are forbidden under the [prohibition against consuming] exposed liquids. [However,] hot water, as long as it is steaming, is not subject to the [prohibition].

[With respect to] a spring, as long as it flows, the prohibition of exposed liquids does not apply, said Rabbi Yishmael son of Rabbi Yochanan ben Berokah. It so happened that Rabbi Yochanan ben Berokah went down to visit Rabbi Yochanan ben Nuri in Beit She'arim, and he came across a pool that did not have three logs [of water in it], and he kneeled down and drank from it. (See Y. Ter. VIII.3.29).) [However, exposed] wine, whether in vessels and whether in the earth, is forbidden.