# Mold in cat water dish **URL:** \ **Category:** Factual Questions\ **Created:** [June 26, 2018, 3:49am UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752 "2018-06-26T03:49:39Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [June 26, 2018, 3:49am UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/1 "2018-06-26T03:49:39Z")
I recently bought this water dish for my cats: > **[PETSAFE Drinkwell Multi-Tier Plastic Dog & Cat Fountain, 100-oz - Chewy.com](https://www.chewy.com/petsafe-drinkwell-multi-tier-plastic/dp/48096?utm_source=google-product&utm_medium=cpc&utm_campaign=hg&utm_content=Drinkwell&utm_term=&gclid=EAIaIQobChMItriSgrXw2wIVGL3sCh1KkAbtEAQYAyABEgIRcvD_BwE)** > > Buy PetSafe Drinkwell Multi-Tier Plastic Dog & Cat Fountain, 100-oz at Chewy.com. FREE shipping and the BEST customer service! It gets black mold on the underwater parts. I follow the washing instructions thouroughly. I took it all apart (even the motor) yesterday and soaked the parts in hot water then cleaned. And today the mold is back. I even changed the filter. Any suggestions on why and what to do about it? Thanks. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [June 26, 2018, 4:02am UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/2 "2018-06-26T04:02:55Z")
Do you have well water? ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [June 26, 2018, 5:12am UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/3 "2018-06-26T05:12:53Z")
No, California tap. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [June 26, 2018, 5:26am UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/4 "2018-06-26T05:26:40Z")
I got nothing. Maybe you should contact the manufacturer. It shouldn’t get moldy in one day. ETA I was thinking of buying a similar one. I think I will hold off, now. ---
**Author:** ![campp](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@campp](https://boards.straightdope.com/u/campp)\ **Post date:** [June 26, 2018, 12:15pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/5 "2018-06-26T12:15:40Z")
How often do you clean it? That’s normal growth, especially in the summer months. I change my filter monthly and wash it down twice a month (scrub parts clean, fresh water). EDIT: Oh, one day. Hmmm. That sounds impossible. I got nuthin’ ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [June 26, 2018, 1:24pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/6 "2018-06-26T13:24:53Z")
I had a similar but earlier model and it never fouled up that quickly. First thing might be to check the filter. That could have some contamination even if brand new. The one I had used a fairly simple charcoal and synthetic fabric pad that honestly seemed more like a place to breed mold than to really filter anything. Water tended to just bypass the filter anyway so I gave up on it. I would suggest cleaning with a bleach solution rather than just hot water. Rinse thoroughly and allow to dry before refilling for use. Dishwasher detergent can work too because it usually has bleach and doesn’t foam up so it’s easier to rinse off. Try running without the filter if you can to see if that’s the culprit. Boiling the filter can work too, but depending on the design it can also destroy it (cartridge filters like in Pur/Brita pitchers have membranes inside that boiling destroys so all the carbon granules go everywhere). ---
**Author:** ![excavating\_for\_a\_mind](https://avatars.discourse-cdn.com/v4/letter/e/e8c25b/32.png) [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)\ **Post date:** [June 26, 2018, 1:25pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/7 "2018-06-26T13:25:31Z")
Use bleach. After cleaning, soak in a solution of 1 Tablespoon bleach per gallon of water for 10 to 20 minutes, then rinse. If it returns within a week, consider adding a teaspoon of bleach to the water one night per week to the container. If you leave it running, the bleach will dissipate within a few hours. At this level, it is not going to harm the cat even if it should drink some (which is unlikely, if you add it at night). Do not use bleach on stainless steel. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 26, 2018, 1:36pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/8 "2018-06-26T13:36:58Z")
I have that exact same water dish, and when I was out of town last week my wife told me that it had mold. So far it hasn’t returned but I’d also suggest running it with a little bleach and then putting fresh water in for your pets. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [June 26, 2018, 7:18pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/9 "2018-06-26T19:18:42Z")
Thanks everyone for the good suggestions. I’ll give them a try. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 26, 2018, 10:21pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/10 "2018-06-26T22:21:29Z")
I have that same fountain, and have never had mold problems. Check the filter, maybe replace it just in case. If you clean with bleach, rinse very thoroughly – probably several times. Cats can smell much better than you, and may avoid drinking if the water has a bleach smell. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 26, 2018, 10:23pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/11 "2018-06-26T22:23:33Z")
I have that same fountain, and have never had mold. Check the filter; maybe replace it just in case. If you clean it with bleach, rinse very thoroughly – cats can smell much better than you, and may avoid drinking if their water smells of bleach. ---
**Author:** ![AlsoNamedBort](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alsonamedbort/32/3213_2.png) [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)\ **Post date:** [June 26, 2018, 10:28pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/12 "2018-06-26T22:28:20Z")
I have the same fountain. I soak it in diluted vinegar overnight and then run it through the dishwasher. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [June 27, 2018, 12:35pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/13 "2018-06-27T12:35:09Z")
> [@excavating\_for\_a\_mind](#): > > [snip] … Do not use bleach on stainless steel. Why not? … I use bleach to clean my cats’ water dish and it hasn’t done anything bad, and that’s straight out of the bottle too … ---
**Author:** ![H0ss](https://avatars.discourse-cdn.com/v4/letter/h/d2c977/32.png) [@H0ss](https://boards.straightdope.com/u/H0ss)\ **Post date:** [June 27, 2018, 7:41pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/14 "2018-06-27T19:41:34Z")
I keep two fountains, so I always have a clean & sterile one on hand if the mold starts before I have a chance to throw it in the dishwasher. I clean the motor & related parts in bleach. I don’t use the filters - they seem like revenue generators at best, petri dishes at worst. Rather, I rinse and change ALL of the water DAILY. This is the only way I would personally feel comfortable drink out of the fountain, which I think is a reasonable standard. Does it work? My 19 year old cat’s urinalysis started to indicate renal failure 2 years ago (when I stepped up my neurosis in an effort to get him to drink more). Last year, he tested in the normal range. Vet was fairly amazed - said “whatever you’re doing - continue”. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 28, 2018, 6:20pm UTC](https://boards.straightdope.com/t/mold-in-cat-water-dish/816752/15 "2018-06-28T18:20:48Z")
> [@H0ss](#): > > Does it work? My 19 year old cat’s urinalysis started to indicate renal failure 2 years ago (when I stepped up my neurosis in an effort to get him to drink more). > Last year, he tested in the normal range. Vet was fairly amazed - said “whatever you’re doing - continue”. By the way, yes this 2-level fountain really is very effective in encouraging cats to drink. I used 3 other types of fountains before, and none were as effective as this one. Even when several were available, they preferred this one. Preferred it over some others that cost quite a bit more.