Mine don't drip. I'm using the push-in type and followed the directions given for installation and how high to hang them so the birds can drink easily. No mud, no wet litter.
I started mine on a nipple waterer as tiny chicks. They saw that shiny, silver lever and wanted to peck at it. It was clear they were doing fine with getting water so I took the dish type out an hour after installing their new waterer. No issues here.