Originally Posted by SteveHansen

Dihydrogen Monoxide is commonly known as Water.

It should be found in large concentrations in lakes and streams.

It should not normally be found in gasoline. It used to be that even a little bit of water in the fuel would cause problems for internal combustion engines. They used to sell "gas dryer", which was just alcohol. (Water dissolves in alcohol, which can then run through the engine without causing problems.) But the new gasolines have some percent of alcohol in them already, so a percent or two of water will dissolve in the fuel mix and not cause problems.