http://www.post-gazette.com/pg/07252/815920-85.stm
Well it is "burning" the hydrogen part of the water molecule.I know in hydrogen fuel cell cars allegedly the exhaust is WATER.
You'd also have the salt and oxygen left in the "water" that had been "burnt".
Unless I'm missing something all of these are NATURAL ELEMENTS and thus,by definition, not pollutants.
But the dirt people think CO2 is a pollutant so I wouldn't put anything past them.
Also with respect to the availability of water consider the WATER cycle. It rains (water falls from sky). The water collects and over time changes to water vapor which rises. When it is high enough it cools downs, condenses and falls from the sky again.
If you increase the amount of water vapor (burning water), you increase the amount of RAIN. Sort of that first law of physics, can't destroy or create matter. Can only change its form.