A debris collection bag made of a water permeable material is adapted for removable attachment to a self-contained swimming pool vacuum head that uses a motor driven propeller to generate thrust for picking up debris and forcing it into the collection bag. The bag includes a main upper portion that encloses a collection chamber, and a truncated lower portion with an open end. A sleeve between the upper and lower portions surrounds the bag and contains a releasable cinch cord for securing the bag over an annular rim on the vacuum head. The truncated lower portion tucks upwardly within the collection chamber to provide a frustoconical intake that increases thrust pressure entering the bag, while providing greater self cleaning circulation at the top of the collection chamber and a low pressure area surrounding the truncated lower portion to allow leaves, dirt and other debris to settle without escaping the collection chamber.