The rescue recommends using water bowls over water bottles. The main reason for this is ferrets do not get enough hydration from a water bottle. They can only get a few drops at a time and ferrets are usually too impatient to sit and drink as much as they should. This can lead to long term health issues.
Bacteria and slime grow in the bottom of the water bottle and it is nearly impossible to clean the bottle well enough to get all the bacteria and slime out.
Because the bottle holds more than a day’s worth of water, most people don’t rinse, clean and refill it every day, which causes even more bacteria and slime to grow in it.
Sometimes it’s hard to find a place near the food that’s convenient to put the bottle where it’s at a level for the ferret to reach easily. This means they are drinking even less than is needed.
Water bottles have been shown to wear down the teeth after long term use.