Many years ago I read a magazine article about a study performed, concerning the affect of water in glow fuel. The person conducting the test added water to fuel in small measured amounts to determine the point at which engine performance was degraded and the amount of degradation to be expected with increasing concentrations.

The bottom line is that the water had very little affect until it reached very high concentrations, much higher than we would ever see.

I wish I could find the article. Probably in RCM.