Antonyms for the phrase 'drains away' could include 'accumulates', 'grows', 'increases', 'expands', and 'swells'. Instead of something draining or diminishing, these words suggest growth, expansion, and accumulation. They might be used when describing positive developments, such as a growing economy or an expanding community. For example, rather than saying that the population of a town is draining away, one might say that it's growing or expanding. Similarly, one might speak of accumulated savings rather than drained-away funds. These antonyms suggest a sense of progression, development, and positivity, rather than loss or diminishment.