I always want Bebe's eyes to look 'pretty' which is not always easy. I did my research ahead of time, and learned that water has minerals that show up in dogs tear ducts. Distilled water contains no minerals and is ideal for trying to prevent tear staining. Some areas have very high mineral content in the water . Where I live, there are TONS of minerals in the water, so I bought a few gallons and I gave her distilled water first, then water from the fridge because we have a filter. She never did tear like a lot of them when they teethe, so maybe this helped or maybe I just got lucky. In any case, I still use water from the fridge !! I don't want to take any chances.