A method for a water bottle comprising, coupling a cap to bottle housing such that an interior of the water bottle and the cap form a water-tight region, receiving a button push on the cap, determining with a light sensor whether visible light is present in a vicinity of a UV LED light source disposed within the cap, in response to the push of the button, initiating providing with a UV LED light source UV light to the interior in response to the push of the button and in response to absence of the visible light within the vicinity of the UV LED light source, and inhibiting providing with the UV light to the interior after a period of time after the initiating providing UV light to the interior or in response to determining the visible light being present in the vicinity of the UV LED light source.