Oboreru nara Ore ni Shiro - Osananajimi wa Nikushoku Lifesaver

Chisa's life recently has been difficult: the design company she works at went under and to top it off, her boyfriend cheated on her! To pull herself together, she decides to go back to her hometown. There, she is reunited with her childhood friend, Takumi, who currently works as a lifeguard and saves her from drowning yet again. From there, the two become more intimate with each other, though it seems Takumi is hiding something from Chisa that had something to do with the past when Chisa almost drowned. (Source: Manga Planet)