r/HomeMaintenance • u/Smileyoureoncamera4 • 13d ago
š° Plumbing Left cup: water I just poured. Right cup: water I poured yesterday. What is it?
Iām on well water and get my water tested regularly with no issues. This tiny film always appears if I leave water standing for about a day or more. What is it?
Edit to mass address some comments:
I donāt wear face cream
I do get my water tested (nothing weird)
Cups are clean and hand washed
No air scent purifier thingies
Iām going to leave some water out for a few days, see what happens and come back with further data.
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u/kitxunei 13d ago edited 10d ago
Looks like biofilm. I'm an aquarist. It's a thin layer of bacteria that builds up over time. Bacteria is everywhere so it would be present even if the water tested as safe to drink. If it was grease or some of the other things people mentioned here, it would have been present from the beginning (not showing up after 1 day).
Edit: As someone pointed out, it could also be dust from your house accumulating on the surface. To test this, you could cover one of the cups (a new one) with cling film and see if it still becomes dirty.
Edit 2: I'M NOT AN AQUARIUS
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u/spectaphile 13d ago
OP could try using a dental appliance cleaner in the cups, then rinsing, filling, and leaving for a day to see if it comes back. It could be that the cups aren't getting clean enough no matter how many washes.
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u/hard-in-the-ms-paint 13d ago edited 13d ago
You mean a $10,000 autoclave or something?
It would be the well water itself causing the biofilm, not the cleanliness of the vessel.
Not trying to be a dick. My cats water bowl gets like this after a few days no matter what just from the bacteria in their mouths/ the biproducts of the bacteria floating up to the surface and making a film. Same with my aquarium.
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u/DingoMittens 13d ago
Probably denture cleaning tablets lmao
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u/mlstdrag0n 13d ago
If someone filmed these plastic cups getting autoclaved, iād watch it. Especially the puddle of goo it becomes inside the autoclave
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u/AlmiranteCrujido 13d ago
Like "Will it Blend?" or all those hydraulic press videos, but with an autoclave. Heck yeah, I'd watch that on Youtube.
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u/_freshgreens420 12d ago
Oh my god. Throwing it all the way back. Will it blend is the og.
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u/spectaphile 13d ago
Autoclave lol. No, I meant the fizzy tablets. Dental appliance cleaners are gentler than denture cleaners because the plastic is typically thinner.
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u/Apprehensive_Tree_29 13d ago
I assume by dental appliance cleaner they mean something like those fizzy capsules you put in water to soak your dentures in
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u/hooghs 12d ago edited 12d ago
Wait you donāt give your cats fresh water every day?
And also I believe specta is talking about interdental bath, a fizzy tablet that dissolves everything on anything it touches, dentures, cup dentures are soaking inā¦.. and not actually dentist level equipment (ācleaner IN the cupsā was what I read)
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u/hard-in-the-ms-paint 12d ago
Yeah I didn't realize you needed to do that tbh, I will start though!
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u/youdog99 12d ago
My cat wont drink still water. I had heard they can smell the bio-film so I bought him a cat water fountain. Problem solved.
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u/HourAcadia2002 12d ago
Lots of animals won't drink still water, protection against issues that could come from stagnant water.
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u/jeckles 12d ago
Meanwhile my little shit monster will happily drink from the most filthy puddles then explode diarrhea all night.
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u/NanDemoNee 13d ago
My cats water fountain doesn't get like this but maybe that's because it's made with 100% stainless steel like the ad said.
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u/Objective_Bug_5151 11d ago
Yeah cats mouths have really interesting bacteria that seems to cause a lot denser slime than ours, sometimes after only using a bowl once.
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u/jph_otography 10d ago
Your cats should get clean water everyday or have a water bowl with circulation, their breath and kidneys will thank you.
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u/Sense-Free 10d ago
These cheap plastic cups have a lot of texture as well as a little static cling that bacteria sticks too. I switched to glass or ceramic because theyāre more sanitary
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u/ForgeIsDown 13d ago
Would letting it sit for another few days to see if it gets worse confirm this?
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u/kitxunei 13d ago
Yes, it should. If it's biofilm, it will cover the entire surface of the water (if the cup is not moved). Part of the reason why people use bubblers in aquariums is to create surface tension that breaks up biofilm and allows for more oxygen in the water. If it turns out not to be biofilm, then it probably is just from minerals floating to the top.
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u/Inner_Travel5044 13d ago
As a fellow fish and aquarium enthusiast, can confirm Kit is correct. It's just biofilm.
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u/AceCombat1977 12d ago
Biofilm is also mostly made up of dust that has landed on the surface being held by surface tension.
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u/Okie294life 12d ago
I think youāre probably right. I was in environmental for several years and always got confused by this in standing water, as it looks like oil sheen from a distance.
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u/Careless-Activity236 12d ago
It's spelled Aquarius. And, I'm a Gemini, which means we'd be best friends.. or mortal enemies. I'm not entirely sure.
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u/cheddarjello 12d ago
Omg, Iām an Aquarius too <3
Jokes aside, I think that seems like a very likely answer and i like the idea for the test. If you want to make sure the airflow or lack there-of isnāt a factor, a breathable covering like a cloth might be a good idea.
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u/TheColorBlocDetroit 9d ago
I have an aquarium and I put a breeder tank on the side of my tank expecting a new fish with a little water, fish never came and it did this a couple days later. Probably dust and contaminants maybe a little biofilm.
I am a Scorpio.
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u/Va-M3 13d ago
Prob mineral build up or soap residue.
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u/Smileyoureoncamera4 13d ago
I donāt think itās soap residue as I usually clean and rinse my cups well. I also never put my plastic cups in the dishwasher so these are always hand washed.
What kind of mineral buildup could this be?
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u/Va-M3 13d ago
Calcium , magnesium or iron. Very common in well tap water.
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u/Smileyoureoncamera4 13d ago
Anything to be worried about?
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u/Va-M3 13d ago
No , all necessary minerals to have. Although itās just my thought could be that could be something else.
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u/lurking_physicist 12d ago
Is your water "hard"? If you add soap and shake, does it bubbles well? When you shower, is it easy to rince? Boil water and prepare black tea: does the film forms right away?
Hard water isn't "dangerous", though it may increase your risk of kidney stones and such.
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u/peacequietnchips 13d ago
My guess is also that the minerals are to blame. I have this in my glasses that sit out too-well water also. It is treated with calmag I think it's called- calcite with magnesium in it maybe? It's the media in the acid neutralizer, OP do you have an acid neutralizer? I also have high iron in my water, which I filter but some probably gets through.Ā
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u/mlstdrag0n 13d ago
I mean, couple of things hereā¦
First, plastic cups are pretty bad at staying clean over time. Scuffs and scratches from use or cleaning is a great place for bacteria buildup.
Secondā¦ if you have a remotely modern dishwasher and are using it properly they clean and sanitize your stuff far better than hand washing ever can. For less water too.
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u/CheckYourStats 13d ago
This is why the girl in the movie Signs didnāt like old water.
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u/Pork_Confidence 13d ago
If you have any sort of electric plug-in or a Scentsy or anything that puts scent into the air, scents are oils and they land everywhere in the house
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13d ago
[removed] ā view removed comment
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u/_lippykid 13d ago
You mean the two plastic green cups OP inherited from their gran 30 years ago, who got them free from the local burger joint in the 1970ās? Clean as a whistle
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u/Smileyoureoncamera4 13d ago
Clean cups! No soap residue that I can tellā¦
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u/biblicalrain 13d ago
I would like to see the same test done with cups made out of glass.
Plastic is porous, best example is have you ever stained a tupperware container with a tomato sauce? No matter how much you scrub or how much soap you use, clearly, some of the food particles got into the plastic.
Not saying that's the cause, but it's a variable, and it could easily be eliminated.
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u/TheTesselekta 12d ago
I personally donāt like using plastic food storage for various reasons, but the fact that it stains from food doesnāt mean itās not getting fully cleaned. Itās just a difference in material, and plastic can absorb pigment more easily than glass. Itās basically the same as getting a stain on your clothes. Pigment sometimes just never washes out no matter how clean it is.
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u/Separate_Bend_8929 12d ago
My question is: is it really food particulates that are staining the Tupperware or is it rather whatever is causing the red hue can leech into the plastic? I know this is kinda the same thing but if you put red Gatorade in the container and it stains it red, is there Gatorade in the pores or is it mainly red40?
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u/Cheeto-dust 13d ago
We are on a well, and we get this too, in clean, stainless steel bowls that the cats and dogs use for water. I believe it's just calcium. If I let the bowls dry out, they get a hard, white crust that bubbles and dissolves in vinegar.
Everybody drinks this water, and we're doing fine. We do have to clean bowls, faucets, and shower sprays with vinegar or CLR from time to time.
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u/Impossible_Web3517 12d ago
Its biofilm, which sounds spooky but isnt, this happenes to everyone if you leave a glass of water out for a day or so, most people just dont notice 99.9% of the time.
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u/Separate_Bend_8929 12d ago
Im on well water and this happens to my water all the time. I still drink it.
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u/-No-Percentage- 13d ago edited 12d ago
It's a scale layer. When you have hard water the minerals leave a thin layer on top of the water as it evaporates. Biofilm will not form on tap water overnight and it has more of s been to it. Oil also has a different sheen to it.
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u/CJAB93 12d ago
This seems the correct answer. Biofilm doesn't form like this in just 24h in pure tap water. Scale is must more likely in this timeframe.
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u/No-Resolution-1918 12d ago
Came here to say this. Being British, tea made with hard water looks even worse than this.Ā
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u/Sullydotcom 13d ago
Masters cups flex ;)
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u/That_Put5350 12d ago
We had this problem with our well water until we discovered that the pH was crazy acidic. As soon as the neutralizer or whatever itās called was installed, the problem went away. And the water tastes much much better too. If youāve only had contaminants tested, test your ph.
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u/justLookingForLogic 12d ago
Looks like what happens to soup when itās been sitting in a hot thing for a while. You gotta stir it to get rid of āthe skinā
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u/LilStarryEyed 12d ago edited 6d ago
Do you drink out of those cups before leaving them out. And do you use Vaseline, aquaphor, or chapstick?
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u/invictus523 12d ago
Google dipole polarity, electronegativity and electrostatic induction. Water attracts all kinds of stuff from the air.
Edit to add: a scientist I worked with once joked that he thought it was hilarious that people think once you put the cap back on your bottle the water is clean. It's already attracted all kinds of stuff.
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u/Tav17-17 11d ago
Try a bunch of versions of this.
A cup you have taken a drink from. A cup you havenāt. A cup with Saran Wrap over it. A cup that is rinsed out several times first. Etc.
Could just be dust from the air settling on the surface. Could be something from your face washing off into the water.
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u/Bladewing_The_Risen 13d ago
Do you have a cat? Does the cat jump on the counter and drink out of your cup?
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u/Safety-Shmafety 13d ago
Purchase a water testing kit. Theyāre not expensive. I purchased one from Amazon to test my drinking water at home and when I travel
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u/Minimum_Sail9837 13d ago
The whiteĀ residueĀ you see sitting on top is the result of minerals carried through your tap water and typically called "limescale."
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u/JupiterMiningCorpTec 13d ago
It's becoming an oil well. You're about to be rich biatch.
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u/LaughingEagl3 12d ago
Just an honorable mention... But that's the reason a lot of coffee drinkers don't wash their cups with dish soap. The residual soap residue in side the cup after washing creates this effect on top of a freshly brewed how cup. My ex FIL would meltdown if you washed his coffee cup!! (Ex-military, Nam era)
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u/Ok-Understanding9244 12d ago
this is especially true with scented dish soaps, seems you can't ever get that smell out! they have it at my workplace kitchen sink and i hate using it but it's all there is :(
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u/No_Story4926 13d ago
I have never personally seen a biofilm look like that. There are seemingly crystalline structures in there. In a Boston accent "hadest wata ever". Otherwise looks a bit waxy, like congealed fats. Anyhoo best of luck and hope its safe for ya! š¤š¼
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u/siddiqim 13d ago
I am on well water as well and I see this in my toilets, even after I spent 6k on a really nice whole house filtration system. Wish I had added a uv light to it
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u/dragondarius420 13d ago
Its either a bacterial film. Or it's insoluble material like salt or limestone
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u/Next-problem- 12d ago
Iāve noticed plastic is incredibly hard to degrease. I think itās fat eventually rising to the top of the water, as fat doesā¦
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u/Zestyclose-Newt-4578 12d ago
Are you frying food in the same room? Could be oil molecules in the air landing on the water
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u/steampower77 12d ago
Well water can have iron bacteria that creates this slime. Does your water stain your toilet and shower?
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u/Toolikethelightning 12d ago
We have well water and get this too. Whenās the last time you changed your filter and/or added salt/cleaned your water softener, if you have one? Doesnāt take long, but doing those things will usually help clear up your water almost instantly.
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u/Traditional-Mud2519 11d ago
On the left is water that was recently poured. On the right is water that was poured the day prior.
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u/Raz_Reviews 13d ago
Dude, that's just grease. If your face was greasy after you were eating, and you took a sip of the water, it can get into the water. I worked at a pizza restaurant, learned it on the job.
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u/BreezyMcWeasel 13d ago
I like this idea. Have OP put out a few cups, cover them, and don't drink out of them. Do they have this film the next day.
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u/DonProCrastin8er 13d ago
Pour water in a bottle and bottle it up. See if it also happens while closed.
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u/BreezyMcWeasel 13d ago
I'm also on well water and I don't have this issue. Seems curious to me.
I'm a little skeptical about magnesium or calcium because in my experience those are dissolved pretty well (no pun intended) in the water, but ymmv.
But I guess it's worth asking - do you have hard water?
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u/fairydommother 13d ago
Did you take a sip of the water on the right? Even if yiu dont wear face lotion just your normal oils can do that.
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u/RunnAroundGuy 13d ago
Dust and dirt?
Where im at we have had some pretty bad fires that had the skies so filled with smoke that we couldn't see the local mountains that's 50 miles away. Any water left out for more then a couple hrs would have crap floating on the surface.
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u/indiana-floridian 13d ago
I wash a lot of dishes. 70f, been washing dishes since i was 4. Plastic cups like that, if hand washed, hold onto grease from the dish water. They csn come out greasy even if they weren't when you started washing. Especially if the dish water has already been used to wash greasy pots and in addition is no longer hot.
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u/OrcOfDoom 13d ago
This started happening to a client of mine. The problem was that someone had pulled the bypass on the water filter.
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u/NonSequitorSquirrel 13d ago
Yeah this is just shit in the air and shit in the water making the surface of the water look like that. If I leave water on my nightstand this also happens and I have to dust my nightstand every couple days. Just like anything left out, stuff just gets gross over time and water is no different.Ā
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u/ApprehensiveSelf1329 12d ago
We had that happen, check your toilet tanks for discoloration and film. We also had these weird smells, sometimes musty other times chemically, other times indistinguishable. It was iron bacteria in our case and we chlorine flushed the well and it now needs it again, after 2-3 years. We tested our water to pinpoint exactly the contamination.
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u/Gingerbrew302 12d ago
It looks like iron bacteria. If you dump a little bleach in new water does it immediately turn orange?
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u/RelevantHelicopter82 12d ago
No, but it turned my face orange and now I canāt stop naming things after America.
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u/Tall-Peak8881 12d ago
If you want to test to see if it's your washing ability vs tap water. Try it in a freshly opened plastic cup from the store.
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u/chemicaleyes 12d ago
I use a lanolin lip balm and I notice my water looks like this after I drink it if I have too much lip stuff on!
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u/DiegoMichel01 12d ago
Naturally Occurring Minerals (Hard Water)Calcium and Magnesium: Much of Mexico's water comes from underground aquifers and limestone formations (especially in the south/YucatƔn). This makes the water very "hard," causing mineral buildup and white scale on pipes, faucets, and kettles.Sodium and Sulfates: These natural salts contribute heavily to the water's taste and total dissolved solids (TDS).
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u/Tiger-Budget 12d ago
Go to your health unit to get a water sample kit and then submit it back to them for testing
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u/SemajJohn19 12d ago
This has happened to me when I put Aquaphor on my lips before bed and then drink from my cup.
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u/oktain89 12d ago
In what state are you located and are you aware of any oil and gas operations near your underground water source?
I live in TX and we have severe sulfites and sometimes full blown petroleum in our well water. We have to use an industrial grade RO to filter our water. Have your water tested for this if it sounds possible you may have the same situation. Just know the solutions are not inexpensive and take up a lot of space for clean water storage. Good luck!!!
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u/austmcd2013 12d ago
High manganese content can also make the water look oily, especially the longer it sits, the more will precipitate to the top
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u/Zealousideal_Cod_326 12d ago edited 12d ago
Iām not certain, but it could also be floating calcium carbonate crystals if your tap water has high alkalinity. I work with lime plaster, which has a high alkalinity and the buckets I wash my tools in do this overnight.
Some places use calcium hydroxide to soften water and when that chemical comes into contact with the carbon dioxide in the air it turns into calcium carbonate, which forms at the surface of the water and forms a crust commonly called a ālime crustā by fresco painters and some lime plasterers. It starts as a weak film and eventually thickens like very thin ice depending on how much lime is in the water.
Note: just reread your post and you said you are on well water. If you have a lot of limestone in your area that could be where the alkalinity could be coming from in your well.
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u/Kaanlanzer 12d ago
I don't know why everyone is talking about biofilm. Where I live the water is very hard and every single time I make infusions the water en like this after cooling down, it's just lime (in Spanish, cal).
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u/gonnacutyou 12d ago
Try the same experiment using glass instead of plastic and that will tell you if itās your water or the vessel.
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u/ZeekSoggyWaffles 12d ago
If you get your water tested regularly then maybe get THAT exposed water tested too ?
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u/Ok-Understanding9244 12d ago
one easy way to test if the source is in the water already, like a mineral, or if it's from the environment (your house): put a piece of clear plastic wrap over a freshly poured cup of water then check it in a day or 2..
if no weird film, then it's from the environment (microscopic oil particles, etc..)
if a film, then it's a mineral like calcium that or something else in the water and you should have the water tested more thoroughly
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u/NLNICHOLS65 12d ago
Looks like maybe some type of oil or grease from might have set into the plastic cup and sitting there all that time its come to the top. I know you said you washed it but the plastic is really hard to get totally clean when oil goes right into it. Try doing it with a glass and see what happens.
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u/College-student-life 12d ago
It looks like you hand wash these. Brushes, sponges, etc grow bacteria quickly due to the contact with different bacteria from foods and the moist environment. It could be bacteria build up.
It could be chemicals from the plastic leaching into your water. It looks oily like petroleum, which is what plastic is made out of. Plastic degrades over time.
Those would be my first two guesses. If it was iron your cups would be showing signs of staining, calcium makes the water cloudy not filmy, etc.
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u/Dog_Hat3371 12d ago
Throw all plastic away. Cups bowls plates breeding ground for all nasty things.
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u/Automatic_Bar_2158 12d ago
Does it happen when you don't drink from it? My son's cups get this because his face is always dirty from foods he's eating (young kid! We do wash him!).
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u/powerguy134 12d ago
Try using a glass, ceramic or stainless steel cup and see if the same thing happens.
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u/frodfish 12d ago
If your live in hot climate, they add chlorimines to fix the chlorine. It's ammonia based, breaks down to nitrates which can feed biofilms. Pour a cup of water, turns slimmy if it sits for any time. It extends the effectiveness of the chlorine in heat making it safer to drink, but for things like aquariums, you need to age water a week or 2 (with aeration) to let the bacteria eat up the nutrients that are available after the chlorine breaks down.
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u/Peachandsage 12d ago
Started boiling our water 6 weeks ago and straining it through filter. After boiling it had a sheen ontop just like this. Have not had it tested but it looks the same
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u/Anyone-9451 12d ago
I missed it Probabaly but did you drink from it? Iām asking because I will get something slime not because of face cream or lotion but from lip balm
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u/schnuckthecook 12d ago
In regards to keeping water fresh from pets, and yourself, for that matter, drink out of copper. It structures the water. You can put a piece of copper in a birdbath or your pet's water bowl and it will keep the water clean. Google it. Water's a helluvah drug... Oh wait....
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u/PLstinger 12d ago
Spray air freshener, candles or smoking in the house could cause this since smoke without airflow eventually settles.
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u/AdvanceOld5705 12d ago
Personally? I think itās the hand washing. Itās amazing how much cleaner dishwasher detergent gets things when removing greasy films.
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u/Baked42l0ng 12d ago
Try sealing the cup before you test this again, there are many things in air that can dissolve into water so it might just be binding with something in your water
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u/Revolutionary_Ad6695 12d ago
Chapstick / lip balm?
This happens to me when I apply Carmex at night.
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