Is Poland spring water cooler kosher for Pesach?
Yes, the water itself is kosher for Pesach. However if the hot water spout was used for chametz, such as pouring hot water directly onto oatmeal etc. the spout would need to be kashered by running hot water through while pouring boiling water over the spout as well. Many are stringent not to kasher plastic for Pesach, in which case the spout should be covered and not used on Pesach.
See Igros Moshe O:C 2:92