This paper continues the theme of water delivery to the urban poor, concentrating on informal water vendors, providers of a crucial service to a significant minority of the urban poor. While recognizing that much water vending does not offer an ideal solution, with many disadvantages compared to piped water delivery, water vendors are indispensable as long as water delivery systems fail to provide adequate supplies to the urban poor. This paper examines how water vendors operate and whether this approach can be improved in order to deliver water services more effectively, efficiently and equitably.