Definitely go at it from the bathroom. When you lift the toilet, you should be able to see the problem. You could have a leak in the pipe, but it will be evident. The other post is right. Mess with it yourself first, and if you find that you’re over your head, call a plumber. The charge will be the same, and if it’s something you can fix, you will have a sense of accomplishment when you finish. Not to mention save the money and learn a thing or two.
