An overflow assembly for a bathtub includes an elbow having a first threaded section and a retainer nut having a second corresponding threaded section. The retainer nut is configured to threadably mount onto the elbow. The overflow assembly further includes an overflow cover including at least one overflow opening and at least one vent opening defined therein. The overflow cover is configured to engage with the retainer nut and substantially cover the first threaded section and the retainer nut.