流云归晚
一楼的也对，但这些更生动和贴切：make sure that not a single drop leaks out或tell a story without missing a single circumstance或There must be no leakage of any kind and degree或watertight或leakproof或flawless 或make a proof all-round and without any omission这些都可以表达“滴水不漏”，呵呵，不知帮到楼主没？
