My water in fuel sensor light hasnt come on in a while, I drained anyway and it was full. Is there any way of checking it? and how.

 

Does the wif light come on when the ignition is turned on?

 

When you drain it, save it in a clear jar. Inspect what you drained carefully. If it is all one phase, then add a little bit of water to it. If you see two phases form, then all you drained out was fuel. If it is all still one phase after adding the water, then all of it was water.