Blog - Dog Bowls and Biofilm

Lez Graham discusses dog bowls, biofilm and dog health

Is Your Dog’s Water Bowl Really Killing Them?

A quick note on the source

Before getting into the science, it is worth saying something about the source of the advert.

The post appears to present itself as coming from a vet. However, I could not independently verify the person’s veterinary credentials from the advert itself.

When I looked at the Facebook page, it said it was created in November 2025. At that point, it had around 1,000 followers, followed no other pages, had only three posts, and had no reviews.

I know that doesn’t necessarily prove anything either way, as I myself have just set up another business page that I’m building up from scratch. But in this instance, I would be cautious about treating it as a well-established professional source of veterinary information.

That does not necessarily mean every claim in the post is false, but when strong health claims are made, especially claims linked to kidney failure, strong evidence and reputable sources should be provided.

So rather than focusing on the person presented in the advert, I’ve looked at the claims themselves.

First, what is biofilm?

Biofilm is real.

It is the slimy layer you may sometimes feel inside a dog’s water bowl, especially if the bowl has been sitting for a while. Biofilm is made up of microorganisms, including bacteria, which attach to a surface and form a protective layer around themselves. In practical terms, that means the bowl may need proper washing rather than just a quick rinse.

So yes, dog bowls can become dirty. Yes, water bowls can develop a slimy film. And yes, good bowl hygiene definitely matters.

A Hartpury University study looked at bacteria in canine drinking water bowls made from plastic, ceramic and stainless steel. The study investigated which bowl material harboured the most bacteria over a 14-day period and whether the species of bacteria varied between materials (Wright and Carroll, 2018).

So far, so sensible.

Does daily washing make things worse?

This is where I think we need to be more cautious.

The claim that “daily washing isn’t keeping your dog’s water bowl clean - it’s making it worse” is not supported by the evidence I found. In fact, the general guidance from reputable sources is the opposite.

The FDA advises washing pet food bowls and utensils with soap and hot water after each use (Food and Drug Administration, 2024). The CDC gives specific cleaning guidance for pet supplies and recommends cleaning pet bowls every day for dry food and water (Centers for Disease Control and Prevention, 2026).

For water bowls, a sensible practical approach is to wash them daily, rinse them properly, allow them to dry where possible, and replace bowls that are scratched, cracked, chipped or damaged.

So no, ordinary daily washing is not “making things worse” when it is done properly.

What can make things worse is using damaged bowls, half-rinsing bowls, letting water sit for too long, not cleaning pumps or filters in fountains, or relying on something that looks clean rather than actually washing it.

Does the bowl material matter?

The advert claimed that the bowl material does not matter, but that’s a bit simplistic.

The Hartpury study compared plastic, ceramic and stainless steel bowls and looked at both bacterial quantity and species present in canine drinking water. In everyday practical terms, material still matters because of how easy the bowl is to clean and how likely it is to become damaged (Wright and Carroll, 2018).

Plastic can become scratched. Ceramic can crack or chip. Stainless steel is generally durable and easy to clean, but it still needs washing and should be replaced if damaged or rusty.

No bowl is magic. No bowl is self-cleaning. A good bowl still needs good hygiene.

Can biofilm in a dog’s bowl cause kidney failure?

This is the biggest claim, and it is the one that needs the most caution.

The advert strongly suggested a link between biofilm in water bowls and kidney failure in dogs, and implied that other explanations, such as genetics, may be being overused.I could not find good published veterinary evidence to support that claim.

Chronic kidney disease in dogs is a complex condition. It involves loss of functional kidney tissue over time and often develops over months or years before it becomes clinically apparent. The MSD Veterinary Manual describes chronic kidney disease as usually progressive and often irreversible by the time it is clinically apparent (MSD Veterinary Manual, 2026).

Veterinary sources describe canine kidney disease as complex. In a study of acute-on-chronic kidney disease in dogs, Dunaevich et al. (2020) found that the presumed causes included inflammatory causes, pyelonephritis, ischaemic causes, other causes, and unknown causes.

But that does not mean bowl hygiene is unimportant. It means we need to be careful not to turn a hygiene issue into a scare story about kidney failure without good evidence.

If a dog is drinking more, drinking less, losing weight, having accidents, vomiting, becoming lethargic, or seeming generally unwell, the answer is not simply to buy a fountain. The answer is to speak to your vet.

What about the claim that symptoms appear late?

There is some truth in the general idea that kidney disease can be advanced before obvious signs appear.

Chronic kidney disease can develop over months or years before it becomes clinically obvious. That is one of the reasons routine vet checks, blood tests and urine tests can be so useful, especially in older dogs or dogs showing changes in drinking, urination, appetite, weight or energy levels (MSD Veterinary Manual, 2026).

However, the advert uses this real and worrying fact to create urgency around a product ... a true statement about kidney disease does not automatically prove that a dirty water bowl caused the disease. Nor does it prove that a particular fountain will prevent it.

Do fountains help dogs drink more?

You know, some dogs do prefer moving water, and some dogs don’t. Some dogs prefer blowing bubbles before they drink (Faelan), splashing around their water bowl (Ziggy), and some dogs prefer drinking out of puddles (Bart).

For dogs that like moving water, a fountain may be useful - it may encourage them to drink more, and that can be helpful, especially for dogs who are not naturally good drinkers.

But don’t think that fountains are automatically cleaner - they have pumps, filters, corners, tubes, seals and surfaces that also need cleaning. If they are not maintained properly, they can develop biofilm too.

A fountain is not a substitute for hygiene. It is simply another type of water delivery system and if you do use one you have to clean the whole thing - not just the visible bowl section. And just like cleaning out a fish tank, that includes cleaning the pump and filter area too.

The red flags in this type of advert

The advert I was sent used several familiar sales techniques.

• It opened with fear.
• It claimed specialist authority, but the authority was not easy to verify from the advert itself.
• It gave very specific numbers but no accessible study to back them up.
• It used an emotional case study about a dog with kidney failure.
• It suggested that ordinary, responsible owners were unknowingly harming their dogs.
• It introduced one product as the solution.
• It ended with guilt: if you do not act, what happens next is on you.

This kind of fear-led wording should always make us stop and think. Not because every product advert is wrong, and not because every concern is nonsense, but because fear-based marketing can make it harder to stop, think, and weigh up the evidence calmly, especially when we’re scrolling late at night or during the ad breaks on the telly (very guilty of this ...)

When a company or advert makes strong health claims, it should be able to provide strong evidence.

What I would do instead

Simple common sense should always prevail when it comes to dog ownership ...

• Wash your dog’s water bowl daily with hot soapy water.
• Rinse it properly.
• Use a bowl that is easy to clean.
• Replace scratched plastic bowls.
• Replace chipped or cracked ceramic bowls.
• Check stainless steel bowls for damage, rust or worn areas.
• Empty and refill water regularly.
• If using a fountain, clean all parts of it thoroughly and often, including the pump and filter housing.
• Do not assume that moving water means clean water.

And, most importantly, if your dog’s drinking habits change, speak to your vet, because changes in how much our dogs drink can be an important indicator of their health.

• Drinking more can matter.
• Drinking less can matter.
• Changes in urination can matter.
• Lethargy, weight loss, vomiting, loss of appetite and accidents in the house should not be dismissed.

My conclusion

I found no good evidence that ordinary water-bowl biofilm is a common hidden cause of kidney failure in dogs, nor that one particular fountain can prevent kidney disease.

I also could not verify, from the advert itself, the source of the claims, the case numbers, the informal “trial”, or the named university study.

I did find that biofilm is real, dirty dog bowls are not ideal, daily cleaning is sensible, and some dogs may prefer drinking from a fountain, whereas some just want to play with it.

So ...

• Clean the bowl.
• Keep the water fresh.
• Use common sense.
• Be wary of scare tactics.
• And if your dog’s drinking or urination changes, speak to your vet rather than relying on a product advert.

As ever, it is not about panicking ... it is about working out what is genuinely useful, what is exaggerated, and what is just there to make us click “buy now”.

Lez Graham MA.

References

Centers for Disease Control and Prevention (CDC) (2026) About cleaning and disinfecting pet supplies.
Available at: https://www.cdc.gov/healthy-pets/about/cleaning-and-disinfecting-pet-supplies.html
Accessed: 4 July 2026.

Dunaevich, A., Chen, H., Musseri, D., Kuzi, S., Mazaki-Tovi, M., Aroch, I. and Segev, G. (2020) ‘Acute on chronic kidney disease in dogs: etiology, clinical and clinicopathologic findings, prognostic markers, and survival’, Journal of Veterinary Internal Medicine, 34(6), pp. 2507-2515.
Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7694831/
Accessed: 4 July 2026.

Food and Drug Administration (FDA) (2024) Tips for safe handling of pet food and treats.
Available at: https://www.fda.gov/animal-veterinary/animal-health-literacy/tips-safe-handling-pet-food-and-treats
Accessed: 4 July 2026.

MSD Veterinary Manual (2026) Renal dysfunction in dogs and cats.
Available at: https://www.msdvetmanual.com/urinary-system/noninfectious-diseases-of-the-urinary-system-in-small-animals/renal-dysfunction-in-dogs-and-cats
Accessed: 4 July 2026.

Wright, C. and Carroll, A. (2018) ‘Microbiological assessment of canine drinking water and the impact of bowl construction material’, poster presented at the 69th Annual Meeting of the European Federation of Animal Science, Dubrovnik, Croatia, 27-31 August.
Available at: https://pure.hartpury.ac.uk/en/publications/microbiological-assessment-of-canine-drinking-water-and-the-impac/
Accessed: 4 July 2026.

first published 5 July 2026

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