That is what I'm afraid of. Not being able to unscrew it when I need to change the water. I have Rheumatoid Disease, and sometimes my hands just refuse to do what I want/need them to. I'm on the look out for something simple and easy. Thinking about the nipples or cup waterers.
Now that I look at the pic, I can see it's a dump wheelbarrow! Is it a single or double wheel variety? I've looked online at the doubles at Lowe's, and seriously thinking about getting one. We just got a wheelbarrow few weeks ago, and got the mid size. It takes all I've got to dump the thing when it's only half full of dirt!