An EUV light source plasma source material handling system and method is disclosed which may comprise a droplet generator having a droplet generator plasma source material reservoir in fluid communication with a droplet formation capillary and maintained within a selected range of temperatures sufficient to keep the plasma source material in a liquid form; a plasma source material supply system having a supply reservoir in fluid communication with the droplet generator plasma source material reservoir and holding at least a replenishing amount of plasma source material in liquid form for transfer to the droplet generator plasma source material reservoir, while the droplet generator is on line; a transfer mechanism transferring liquid plasma source material from the supply reservoir to the droplet generator plasma source material reservoir, while the droplet generator is on line. The supply reservoir may comprise a solid form of the plasma source material used to periodically form from a portion of the material in solid form the material in liquid form.