Dishwasher Detergent + Rinse Aid on Dog Bowls: Could Daily Residue Be a Long-Term Risk?

When we got a new dishwasher, the manufacturer's "recommended detergent and rinse aid" caught my attention and made me dig out an article I read in 2023.

Mounting evidence shows that dishwasher detergents and no-spot rinse aids can leave chemical residues on dishes, even after a full wash cycle.

So, if you wash your dog's food and water bowls daily (and you should), what happens when your dog licks that bowl every day - for years?

This isn't hype or fear-mongering. It is about understanding exposure. Dogs don't just eat from bowls. They lick them clean.

Let's break down what's in dishwasher detergents and rinse aids, what the science actually tells us about residue left on dishes after being washed, what's still unknown, and the simplest ways to keep bowls clean while minimizing unnecessary chemical exposure.

First: Yes, You Should Wash Pet Bowls Daily

Pet bowls can develop biofilm (a sticky layer of microbes) quickly - especially wet food bowls and water bowls. Multiple public health and veterinary-facing resources recommend frequent cleaning (often daily, and after each wet meal).

So the goal is not to stop washing dog bowls because obviously, clean bowls matter.

The goal is wash them daily while minimizing chemical residues.

Why Is This Important?

A 2023 research paper reported that some rinse aid surfactants, including alcohol ethoxylates, showed biological activity at very low concentrations in laboratory gut samples. Based upon these findings, the authors highlighted concern that rinse aid residues remaining on dishes after the dishwasher use may not be biologically inert. In other words.... some rinse aid ingredients remain active at low levels, suggesting that residues left on dishes after washing may matter more than previously known by appearing in gut samples and therefore have potential to upset the gut microbiome.

Even the American Cleaning Institute has published a response page discussing this research and dishwasher detergent/rinse aid safety: We have enough signal to justify "practical precaution," especially for animals with smaller body size and higher lick exposure.

What's in dishwasher detergent (and why)

Dishwasher detergent is not like dish soap. It's engineered for:

• high alkalinity
• breaking down fats/proteins/starches
• preventing redeposit
• working with hard water
• doing all that with minimal scrubbing

That's why ingredient lists can look intense.

🧫 Common dishwasher detergent ingredient categories:

1. Alkaline builders (high pH cleaners)These ingredients raise pH to help break down fats, proteins, and dried -on food.  

Examples:

Sodium carbonate, sodium silicates, metasilicates

Why they matter: Effective cleaning depends on alkalinity, not using extra detergent which can leave residue, reduce rinsing efficiency and increase film buildup on dishes.

2. Bleaching systems

Used for stain removal and "sparkle".

Examples:

• Sodium percarbonate is an oxygen bleach that breaks down in hot water into hydrogen peroxide and sodium carbonate to dissolve  baked-on food, remove stains, and brighten dishes without chlorine bleach.
• Bleach activators like TAED (Tetraacetylethalenediamine) react with the hydrogen peroxide to create a stronger cleaning compound called peracetic acid which makes the oxygen bleach work faster at lower temperatures.

Why they matter: These increase cleaning power but also increase chemical activity during washing, making recommended usage and rinsing important.

3. Enzymes

Biological enzymes that break down proteins, starches, and fats.

Examples: Protease, amylase (often present in "all-in-one" tablets)

Why they matter: Enzymes allow detergents to work more effectively with fewer harsh chemicals, but they are still biologically active compounds intended to be rinsed away.

4. Surfactants (specifically - wetting agents)

This category matters the most. Surfactants reduce water's surface tension so food residue can lift away from dishes. Common examples include alcohol ethoxylates and other nonionic surfactants. These ingredients are designed to remain effective at very low concentrations, often forming an intentionally thin functional layer to improve sheeting and prevent filming on the dishes.

Why they matter: Research has specifically identified surfactants - especially those used in rinse aids - as biologically active at trace levels in laboratory gut samples, making residue a very high concern.

5. Polymers / anti-spotting / anti-redeposition agents

This is the core of the "spot-free" issue. These ingredients are added to prevent minerals, detergent residues, and food particles from depositing onto dishes as water evaporates.

Examples: Polycarboxylates, dispersants, chelating polymers (varies by formulation).

Why they matter: Anti-spotting agents are designed to stay on the surface long enough to alter how the water dries so their function closely over-laps with rinse aid surfactants. Spot prevention isn't about cleaning - it is about surface modification of the dishes themselves. Anti-spotting systems exist to leave behind a functional effect. For dog bowls that are licked clean, this makes residue REALLY IMPORTANT!

Built-In Tablet Claim	Separate Rinse Aid
Polymer-based agents	Surfactant-based
Dispersed during wash	Concentrated in final rinse
Prevents redeposition	Promotes sheeting
Lower residue concern	Higher residue relevance
Often fragrance-free	Often fragranced

The ingredient type most discussed in the science: alcohol ethoxylates

The 2023 research paper identified alcohol ethoxylates in rinse aid as a likely driver of the observed epithelial barrier damage in lab samples.

Again - that’s lab samples, not a dog study. While there is not a guaranteed real-world outcome (for dogs), it's strong enough evidence to justify an easy precaution:

Don't use rinse aids on pet bowls. That’s the bottom line.

6. Fragrance

Fragrance has no functional role in dishwasher detergent and is added purely for scent (for human preference. Your dishes don’t care).

Why they matter: Fragrance compounds are common irritants and provide no cleaning benefit. Fragrance-free formulas are always preferable for both people and pets!

7. Dyes

Dyes or colors serve no cleaning function and are added solely for appearance to make them look like powerful cleaners!

Why they matter: They increase the chemical load without improving performance and can contribute to unnecessary chemical exposure.

8. Preservatives

Used to prevent microbial growth in liquid or gel formulations.

Why they matter: Preservatives are more common in consumer products than people realize, especially in products marketed as "fresh" or "lemon," or "clean" scented.

The real-world "risk equation" for dogs

There are three parts to the equation for weighing risk.

Residue + Exposure + Sensitivity

1) Does residue remain on bowls?
Residue can remain depending on the product, how much is used, dishwasher performance, water hardness, and cycle type. **This is the core concern raised in the study discussion and the broader conversation.**

2) How much exposure does your dog get?
Dogs lick bowls. Some dogs lick a lot and that dish is clean looking before going into the dishwasher! Small dogs and puppies get a higher dose per body weight.

3) How sensitive is your dog?
Dogs with GI sensitivity, IBD-like symptoms, leaky gut, allergies, or are immuno-compromised may be more reactive to low-level irritants (not proven for these ingredients specifically - just a reasonable precaution mindset).

What We Know vs. What We Don't

What we know

• Daily bowl sanitizing is recommended to reduce microbial risk.
• Rinse aids commonly contain surfactants (including alcohol ethoxylates in many products).
• Lab research suggests some rinse aid surfactants can affect intestinal barrier lab samples at very low concentrations, prompting residue concerns.

What we don't know (yet)

• Whether typical home dishwasher residue levels cause measurable harm in humans or dogs.
• Which brands/formulas leave more (or less) residue in real home usage conditions.
• Which dishwashers are better at removing residue.
• Whether chronic low-dose exposure to dishwasher detergents in dogs contributes to GI, skin, or immune issues.

So the most responsible and proactive posture is: clean bowls daily + reduce avoidable chemical exposure.  

Practical ways to reduce residue on dog bowls

1) Skip rinse aid for pet bowls

If you use rinse aid in your dishwasher, consider:

• washing pet bowls separately without rinse aid, or
• turning rinse aid off if your dishwasher allows
• wash dog bowls by hand after each use

This is the single biggest low-effort change based on the current discussion.

2) Use less detergent than the label suggests 

Many dishwashers do not need a full tablet for lightly soiled dishes. Over use increases residue risk linked to potential gut health.

3) Choose fragrance-free / dye-free / "free & clear"

Fragrance and dyes add zero cleaning value and are among the most common sources of irritation sensitivity for many households including pets.

4) Run an extra water rinse (or a high-temp/sani cycle if bowls are dishwasher safe)

More rinsing + hotter water generally helps with spot removal and drying. (Also helps with bowl hygiene.)

5) Use stainless steel or lead-free ceramic bowls instead of plastic

Stainless is easier to fully clean and less likely to harbor biofilm than plastic, especially if it has become scratched and porous. 

6) Air dry fully

Residual moisture supports microbial regrowth. Let bowls dry completely before refilling.

Ingredient "watch list" for dishwasher products used on pet bowls

Not "panic list" - just what to be aware of so you can avoid them in dishwasher detergent:

• Alcohol ethoxylates / fatty alcohol ethoxylates (common in rinse aids, sometimes detergents)
• Fragrance/parfum
• Dyes/colorants

A simple "best practice" routine for most dog households

If you want a clear, non-obsessive and easy to implement routine:

1. Wash bowls daily by hand in hot water after each use especially after a  wet meal 
2. Dishwasher-safe stainless steel bowl + hot/sani cycle.
3. Make your own DIY rinse.
   Option 1: You can mix up 1/4 cup white distilled vinegar with 1 cup of water and add that to the rinse aid compartment as needed. 
   
   Option 2: You can make a food grade citric acid based rinse aid by dissolving 1 tsp food grade citric acid in 1 cup of warm water and add 1/4 cup of that solution to a small, dishwasher safe cup on the top rack. 
   
   You would NOT want to use either DIY rinse aids on aluminum, cast iron, carbon steel, or decorative/antique glazes, natural stoneware or porous ceramics. You can use DIY rinses on stainless steel, glass, modern glazed ceramic, and porcelain. Recommend it is an occasional use and not every-day. 
4. Use a fragrance-free and preferably detergent-free product (if one can be found!)
5. Don't use more than the recommended amount based on the size load
6. Extra water rinse if your machine offers it.
7. Dry fully.

That's it. Clean bowls, lower chemical exposure, no drama.

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FAQ

Should I stop using the dishwasher for dog bowls?

Not necessarily. Dishwashers can be effective for cleaning and hygiene when bowls are dishwasher-safe, especially with hotter cycles. The more balanced approach is: Keep washing but eliminate the rinse aid and use the correct amount of detergent for the load.

Is rinse aid "toxic"?

"Toxic" depends on dose and exposure route. The most responsible statement is: some rinse aid surfactants show biologic effects in lab gut samples, and residue is a reasonable concern, so skipping rinse aid for pet bowls is a smart precaution.

My bowls look dull and cloudy without rinse aid-what then?

Cloudiness is often minerals/hard water. Try:

• less detergent
• an extra rinse
• occasional vinegar rinse after washing (not mixed with detergent in the wash compartment)
• switching detergents to one with a built-in rinse aid (not extra added separately)

Is "oxy" the same as bleach?

No. "Oxy" refers to oxygen bleach, not chlorine bleach. Oxygen bleach is hydrogen peroxide - based and commonly used in dishwasher detergents. It's less harsh than chlorine bleach but still chemically active.

Are eco-friendly dishwasher detergents safe?

They can be safer in many ways, but "eco" does not mean residue-free. These products still rely on surfactants, enzymes, and alkalinity to clean effectively.

Should I hand-wash dog bowls instead?

Not necessarily, but it may be simpler and easier.  Dishwashers can clean very effectively. The key is avoiding rinse aid, using the recommended amount of detergent based on load size, and ensuring thorough rinsing.

Why are dogs more vulnerable than people?

Dogs lick bowls directly, often thoroughly, and smaller body size means the same residue can represent higher relative exposure over time.

Should I replace my dishwasher?

Short answer: No.

There is no evidence that you need to replace your dishwasher to reduce potential residue exposure for your dog. Dishwashers are highly effective at cleaning pet bowls when used correctly. The discussion around residue focuses on what is added to the wash, not the machine itself.

In most cases, simple adjustments are enough:

• Skip rinse aid for loads that include dog bowls
• Use the lowest effective amount of detergent
• Choose fragrance-free formulas
• Run an extra water rinse cycle if available
• Allow bowls to dry fully before use

These steps reduce potential residue without compromising hygiene - and without replacing perfectly good appliances. That said, if your appliance isn't effectively rinsing or doesn't offer a sanitize option, you may consider an upgrade. 

 

References

1. Ogulur I, et al. Gut epithelial barrier damage caused by dishwasher detergent and rinse aid residues in professional dishwashers. Journal of Allergy and Clinical Immunology. 2023. (PubMed) https://pubmed.ncbi.nlm.nih.gov/36464527 https://www.jacionline.org/article/S0091-6749(22)01477-4/fulltext JAC Online

2. Ogulur I, et al. Gut epithelial barrier damage caused by dishwasher detergent and rinse aid residues in professional dishwashers. Journal of Allergy and Clinical Immunology. 2023. (ScienceDirect mirror) https://www.sciencedirect.com/science/article/pii/S0091674922014774 ScienceDirect

3. American Academy of Allergy, Asthma & Immunology (AAAAI). Gut epithelial disruption caused by rinse aids. 2022. https://www.aaaai.org/tools-for-the-public/latest-research-summaries/the-journal-of-allergy-and-clinical-immunology/2022/gut

4. University of Zurich (UZH). Commercial dishwashers destroy protective layer in gut (media release). 2022. https://www.news.uzh.ch/en/articles/media/2022/Geschirrspuelmittel.html

5. American Cleaning Institute (ACI). Dishwasher Detergent and Rinse Aid Safety. https://www.cleaninginstitute.org/dishwasher-detergent-and-rinse-aid-safety

6. American Cleaning Institute (ACI). Dishwasher Myth/Fact (PDF): Dishwashers and Dishwasher Detergents are Safe. https://www.cleaninginstitute.org/sites/default/files/documents/Dishwasher_MythFact.pdf

7. U.S. Centers for Disease Control and Prevention (CDC). About Cleaning and Disinfecting Pet Supplies. Updated Jan 30, 2025. https://www.cdc.gov/healthy-pets/about/cleaning-and-disinfecting-pet-supplies.html

8. U.S. Centers for Disease Control and Prevention (CDC). Cleaning and Disinfecting Pet Supplies (Infographic PDF). https://www.cdc.gov/healthy-pets/media/pdfs/Cleaning-pet-supplies_web-infographic-H.pdf

9. U.S. Food and Drug Administration (FDA). Tips for Safe Handling of Pet Food and Treats. Updated May 23, 2024. https://www.fda.gov/animal-veterinary/animal-health-literacy/tips-safe-handling-pet-food-and-treats

10. Reckitt Benckiser (RBNA) SmartLabel. FINISH® Jet-Dry® Rinse Aid - Advanced (Discontinued): ingredient disclosure page. https://www.rbnainfo.com/smart-label.php?productLineId=1663

11. Diversey. Suma® Select Rinse Aid - Safety Data Sheet (PDF). Published Dec 4, 2025. https://sds.diversey.com/private/document.aspx?prd=MS0800353~~PDF~~MTR~~ANGH~~EN

12. Swish. Safety Data Sheet (PDF) (Swish-branded product; includes alcohol ethoxylate). https://swish.ca/amfile/file/download/file/4554/product/2151/

13. Ecolab. Swisher Rinse Additive - Safety Data Sheet (PDF). https://assets.pim.ecolab.com/media/Original/10086/US-Z8-918855-01-SWISHER%20RINSE%20ADDITIVE%20%28918855%29.pdf