Mac and Charlie: White Trash
It's Always Sunny in Philadelphia Season 6 Episode 5 (10/14/10)
When Mac and Charlie can't get into a private pool, they attempt to renovate their own pool. Dennis and Dee set out to prove they're upper class and can get in. Mac and Charlie end up getting stuck in the deep end of their drained pool and rely on Dennis and Dee, who couldn't get into the private pool, to rescue them.