If I mix primer and water, will it mess up my project?

So I'm painting the entrance to Moria from lotr and a bunch of trees around it in the outside of my garage, and I want to put primer over the line art so it's safe from weather. Sadly, the primer is too thick and it covers the line art completely to where I can't see it. I want to know if I can mix it with water without messing up the primer or the future paint I'm gonna put on it.