It is definitely possible that he ate something while outside, got ahold of some of the BBQ or simply got stung by a bee or another insect. It is also possible that he is getting overheated by being outside all day since he is not used to this.
It is also possible that after a few days of having local water, his system is not liking it - particularly if it is coming from an outside hose as it will contain lead.
Try feeding him a little pure pumpkin and see if that helps his tummy. If he keeps vomiting, you'll need to find a vet nearby and get him in asap.
__________________  Sissy & Angel |