I don't know what to suggest, as I've never used automatic watering. The water bottles I use were improved upon many years ago with the addition of a metal
drink tube that has 2 metal ball bearings inside to regulate the flow, so they cannot do this. I doubt that the rats will "know" not to do this, & putting a bowl
under the tap might work...IF they don't push the bowl around? Rats will be rats, lol.