A fluid delivery system, method, and apparatus for providing instillation therapy with a negative-pressure source is described. The apparatus includes a housing having an ambient chamber and a negative-pressure chamber fluidly isolated from each other. The apparatus also includes a moveable barrier disposed in the housing between the ambient chamber and the negative-pressure chamber. The moveable barrier is operable to move between a charge position and a discharge position in response to negative pressure. A fluid source is disposed in the negative-pressure chamber and is collapsible in response to movement of the moveable barrier to the discharge position. The apparatus also includes a fluid outlet in fluid communication with the fluid source, a negative-pressure port in fluid communication with the negative-pressure chamber and configured to be coupled to a negative-pressure source, and a vent formed in the housing and fluidly coupled to the ambient chamber.