Why is My Dog Water Bowl Slimy?

Dog water bowls are standing water. Given this fact, we don’t think about cleaning them as much as we should. If left alone, you may find your dog bowl feels slick and slimy on the inside. What exactly is causing that and is it safe for your dog? Should you be concerned?

The technical term for this usually invisible slime is called “biofilm.” Biofilm is made up of organic and inorganic, living and dead matter. Basically, it’s a bunch of bacteria adhering to the side of the bowl, bound by a thick substance (the slime you feel). Another way to think of it – it”s the same phenomenon that causes plaque on your teeth.

Sure, it can be good bacteria, but it can also be bad bacteria. E. coli, listeria, and legionella (a bacteria that causes a “Legionnaires” disease, which represents itself as pneumonia) all love to live in biofilm. Have pink slime? Pink slime is a sign of Serratia Marcescens bacteria being present. It can cause all kinds of problems including respiratory infections, septicemia, pneumonia, conjunctivitis, to name just a few!

Biofilm has been known be the cause of ear, urinary tract and bladder infections, not to mention the risks the aforementioned bacteria can cause.

What’s worse, is when bacteria is ingested within biofilm, it is resistant to your dog’s immune system, meaning it is more likely to survive and cause problems. The bacteria can also separate within the body, creating new biofilms and new infections – spreading quickly. It’s also difficult for vets to identify which bacteria is causing the problem, because culture swabs have difficulty breaking through the biofilm to get at the bacteria. Due to all this, it can require high doses of antibiotics to kill the bacteria once it’s in your dog’s system.

As you can see – biofilm is a bacteria’s best friend, and a dog owner’s bane.

How to Prevent Slimy Build Up in Your Dog’s Water Dish

The best thing to do is to regularly wash your dog’s water bowl – some vet’s say daily, other’s say weekly. At the very least, every time it’s empty. And by wash, we mean with a soap and very hot water, not just rinsing.

Also, ceramic or stainless steel dishes are better than plastic. Plastic is porous and gets minute cracks and scratches that are the perfect places for bacteria to grow where your soap and water can’t reach them.

Following these simple tips can help keep your dog healthier.



12 thoughts on “Why is My Dog Water Bowl Slimy?

  1. Margarita Brown says:

    Thank you for the information!

  2. Deb H says:

    Thank you guys, perfectly timed ! Our ESS had consult last week with a vet specialising in dermatitis. Seems bacterial infections in feet & ears are contributing, mainly ‘hay fever ‘ allergens tho. His water bowl & plastic bucket (backup water source) are definitely going to be well scrubbed from here on. So appreciated !

  3. Sandra Carle says:

    Thank you, I clean the bowls regularly but I don’t use soap. What is the best soap to use??

    1. Robert says:

      Any human grade dishwashing soap is fine.

  4. Wendy J Hearn says:

    Oh that answers that “I wonder why” question 🙂 This article was very interesting to me. I was at work when the email came in & I couldnt wait to finish work to read it! I didnt know this I thought a quick rinse a couple of times & wiping around with my fingers was good enough but now knowing this I will definitely be washing in hot soapy water….

  5. Honi Phillips says:

    Sad that people need to be told to wash their pets water bowls.

    1. Robert says:

      Hi Honi, I think most people do wash them. This is more of a confirmation that its a good idea to do so.

  6. Gemma says:

    Thanks for the information already clean bowls but good to know what is causing the slime. 😊

  7. Mick says:


  8. Angela Cunningham says:

    Thanks Robert. That’s really interesting. My dog has been really sick recently and ended up with a side of his face paralysed. I have noticed his bowl getting a lot of clear slime. He is a French bulldog and with his paralysis is drooling a lot more as his jowls don’t keep it in his mouth. I think that’s why his bowl gets dirty every day. I have now bought an alternating bowl so I can throw one in the dishwasher every day. Thanks for sharing.

    1. Robert says:

      Hi Angela, that’s a good idea. And yes those dogs with loose lips do leak a lot of slime in their water bowls, lol.

  9. Beverley says:

    Thanks for the information. I always wondered about that. Our dog has two small water bowls both rinsed daily. Only one makes it into the dishwasher. Will now make sure both get cleaned properly. 😁

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