I review our current understanding of the origin of Earth's water. Carbonaceous chondrite meteorites -- representative of the outer asteroid belt -- appear to offer the closest isotopic match to Earth's water. Dynamical models have discovered multiple pathways for water delivery to Earth, each of which is linked with a specific model for terrestrial planet formation. The currently favored models propose that Earth grew mainly from local (dry) material, but was "polluted" by a population of planetesimals scattered by Jupiter and Saturn during their growth or orbital migration. By understanding the different mechanisms of water delivery, I extrapolate to rocky exoplanets. While uncertainty remains (e.g., regarding water loss mechanisms), the mechanisms of water delivery remain on relatively firm footing and should be testable in the coming years.