How much water is in a comet compared to that in the earth’s oceans? Is it plausible that a strike on the earth by a large dry rock could cause ocean water to splash out into outer space, in such a way that it would enter a highly elliptical orbit about the sun and become a comet?
One of the links in the comments above has something about a whole lot of comets over a long time period.
In a word, no.