Gooey water dish?

My kitties have one of those big water dispensers (not a fountain, just like an upside down jug on top of the dish) as a] I travel often, for days at a time and b] they drink a lot of water. However, I've noticed that whenever I take it up to refill it (once a weekish) the bottom of the resevoir and the dish itself are covered in slime. It's completely invisible and looks like it's just wet, but it's actually a viscous, nasty slime. I assume it's bacteria buildup, but I'm no expert. I've been washing it every time I fill it, but should I worry more? Is there an issue I'm missing?
Thanks for everyone's help!

Is the water dish in direct sunlight? This can sometimes stimulate algae growth, like what happens to fish tanks. This may be the very beginning of a little bit of algae growing in the bowl. It may not even be a sunlight thing. When water is basically still, stuff grows. If you're away a lot, a fountain may be a better choice than the set up you have now. I use a plain stainless steel water dish myself, but have never experienced what you're describing because my cats drink a dish worth of water a day and the dish is rinsed or washed regularly. I think a fountain with constanly moving water will help eliminate the problem. As far as this being dangerous to your cats, I really couldn't say.

I get the same type of thing in my water fountain...but I probably don't clean it as often as I should. I too wonder if it's something that will hurt them.

Their water dishes must be cleaned regularly!.

I replace their water twice a day because the way i look at it is, would you like to drink out of a dirty glass?, because basically thats what it is

I get that stuff even when it's only been there for half a day. To combat it, I have several glass bowls of water and Miss Kitty just picks between them. I wash the bowls thoroughly every day, but it still does develop.

MKD

What beautiful kitties you have ! I think everyone has that problem . I would think a running fountain would help but after reading the previous post, that might not even cut down on it. I finally got rid of my upside down dispenser because it was difficult to clean and went back to the bowl. I just make a habit of washing them every evening and rinsing them in the evening

The dog bowl and the cat bowl will do that. I rinse them out twice daily and wash them once each morning to avoid it. I think it's from their saliva. Ugh.

Plastic is especially prone to growing bacteria. I'd get rid of it and go to just a plain ceramic or glass bowl for water. Also, plastic bottles break down and will give off chemicals that can be carcinagens. That's why they don't recommend you keep refilling your own water bottle, especially if it was originally a throw away (such as an old Pepsi bottle or recycled water bottle.) Once plastic starts growing bacteria, it is impossible to completely get rid of it. Ceramic or glass on the other hand, you can clean and effectively get the bacteria off.