A mixing spray device adapted to mix an added material with source water supplied from a hose. The mixing spray device comprises a main body and a container that may be detachably attached to the main body. The mixing spray device may be configured to operate in an off configuration in which nothing is dispensed, a water configuration in which only water is dispense, and a mixture configuration in which both water and the added material are dispensed. The mixing spray device may also comprise an attachment assembly that is rotatably connected to a handle portion. The container is detachably attached to the attachment assembly and thus may rotate relative to the handle portion. The container may be provided with a container member, an interface member, and a restriction member. The container may be attached to the main body using a flange on the container and a latch structure on the main body.