Kasei Madoushi no Isekai Seikatsu: Boukenchuu no Kaseifugyou Uketamawarimasu!

Alec, an A-rank adventurer, meets Shiori, a woman with the mysterious appellation “housekeeping mage.” She has so little magical power that she’s useless as a combat mage, but to make up for it, she uses her magic to take care of all the daily chores of an expedition, like washing and cooking, single-handedly. As Alec adventures with Shiori, her novel use of magic provides a warm bath and delicious food...in other words, an environment much too comfortable to be called “camping”! He’s completely taken with her, but she has a certain secret... (Source: J-Novel Club)