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black slime on faucets

Black slime on faucets? Learn what it is and how to get rid of it!

Updated on May 16, 2018

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Have you ever noticed dark-brown or black slime on faucets, spouts, aerators, shower heads, in toilet bowls or other bathroom fixtures? Harmless manganese bacteria causes it, and in this post, I will tell you how to get rid of the black gunk. I will also list methods that do not, or only temporarily, work.

Mentioned Brands and Products

APEC RO-90 – Reverse Osmosis Drinking Water System

Water quality in Atlanta

I was born and raised in Salzburg (Austria), which is not only known for Sound of Music and Mozart but also for excellent water quality. Ok, maybe the last part isn’t commonly known unless you are from there.

In Alpharetta, Georgia, water smells and tastes different. The first thing I noticed when moving here was the chlorine taste in tap water. I keep joking with fellow Europeans, who live in the US, to bring a small bottle of chlorine on trips back to Europe so we can make the water there taste like what we got used to here in the US.

Besides taste, I have noticed another nuisance with our drinking water. Black slime or gunk was building up around bathroom fixtures. On faucets, this nasty stuff seems to accumulate around spouts and aerators and form black flakes or slime. In toilet bowls, you may notice it as dark stains.

What is causing black gunk in faucet aerators?

I found myself removing that black gunk on faucets and spouts a lot lately, so I searched the Internet for answers. Unfortunately, there isn’t a lot of factual information available. Unless you already know what it is, so you can use the proper search terms. Keywords like “black gunk on faucet” often lead to ridiculous answers, such as “call the health department” or “sue your landlord.” So I decided to dig a bit deeper and soon discovered oxidized manganese and harmless bacteria feeding off of it to be the cause of this black slime.

Black slime on faucets? Learn what it is and how to get rid of it!
Black gunk/slime on aerator

Manganese, as well as iron, can stain drinking water, fixtures or even laundry. Most drinking water has traces of dissolved iron and manganese. When these minerals come into contact with oxygen (from water or air), they oxidize. Iron can tint water (and things it comes in contact with, such as fixtures) red and manganese can tint water black.

Manganese is a naturally occurring metal that can be found in different types of rocks, soils, and sediments; and typically occurs in lakes, rivers, and underground water supplies.

The black slime that accumulates on spouts is bacteria that feed on oxidized iron and manganese in the water.

Manganese: A naturally occurring mineral
Manganese: A naturally occurring mineral

Is Manganese (bacteria) harmful?

Neither manganese nor the bacteria are considered dangerous and a risk to your health in levels as they occur in our drinking water. The WHO recommends maintaining a concentration of 0.05mg/l in drinking water. Lower levels can be easily achieved by filtration.

Manganese and iron in drinking water

Depending on the concentration of manganese in your drinking water you have different options. Unfortunately, Fulton County doesn’t spell out manganese levels in its annual Water Quality Report. That is because there are no federal drinking water standards for manganese. So if you want to know how much manganese is in your drinking water, you have to get it tested.

I called our water provider, the Fulton County Water & Sewer Billing and Collection Division. The gentleman on the phone told me that the problem of black slime in water pipes could be resolved by flushing the main line.

Our house was built in 1989, and if the main line was never flushed, I could imagine that mineral deposits, including manganese, built up over the years.

He came out the same day flushed the main line and told me that the problem should be fixed. Unfortunately, flushing the main line did not resolve the problem; we still have the black slime and gunk. I called the county, and someone from the water department came out to run some tests. All ad-hoc tests were negative, and the county employee told me that there was no manganese or iron in the water. At least not at levels that would cause the described issues. That leads to the conclusion that the black gunk in water lines is related to the plumbing of the house.

Besides the most obvious reasons mentioned above, black gunk can also be caused by oxidizing pipes (ours are PVC), dissolving rubber seals in your water heater (ours is brand new), among other reasons.

How to get rid of black slime on faucets

In summer of 2017, we decided to remodel our kitchen and install a reverse osmosis drinking water filter for the kitchen sink. I didn’t expect it would solve our manganese problem and frankly, I didn’t even think about it. Until then, we used a Britta water pitcher with replaceable filter cartridges to filter tap water, but refilling and cleaning that pitcher became a bit of a chore. As a result, we wanted something more convenient that could produce clean and good-tasting drinking water on-demand. I did a lot of research, and we finally decided to invest in an RO-90 – Ultimate 5-Stage 90 GPD Reverse Osmosis Drinking Water System from APEC.

Reverse osmosis fixed the black slime problem

On Sunday, on April 22, 2018, at 5:30 am, I poured a glass of water from the APEC’s faucet before sitting down to write on my blog when it occurred to me that I have not seen a speck of the black slime I see everywhere else in the house. So I unscrewed the aerator of the APEC’s faucet to see if there was any buildup, but there wasn’t!

 Benefits of APEC RO-90
  • Removes 99% of all contaminants, including black-slime causing manganese and iron from tap water
  • Convenient and low maintenance – filter cartridges last 1-3 years (depending on stage)
  • Excellent return on investment
  • No more descaling the coffee maker or steamer

If you think about it, that makes perfect sense because the APEC’s reverse osmosis filtration system removes all minerals and other contaminants from the water, including iron and manganese. That’s also the reason why we don’t have to descale our steam oven or coffee maker when using filtered water – because it doesn’t contain any minerals, such as calcium!

RO-90 – Ultimate 5-Stage 90 GPD Reverse Osmosis Drinking Water System
RO-90 – Ultimate 5-Stage 90 GPD Reverse Osmosis Drinking Water System

Buy on Amazon

What about whole house water filtration systems?

Technically, you could apply the same principal and install a whole house water filtration system. But there are some caveats to consider:

  • Make sure to get a reverse-osmosis (RO) filtration system, and
  • Be prepared to triple your water bill

You can find different types of water filtration systems in the market. Most of them do not use reverse osmosis to filter all of your water. That has two reasons:

  • You need high water pressure to apply reverse osmosis: The pressure from the filtration system back into your water supply line is lower than the intake pressure. That’s usually not a problem for an individual faucet, but it likely is if you try to filter the water from the main supply line.
  • It wastes a lot of water. An RO-based system uses on average 3 gallons of tap water for every gallon of filtered water it produces.

As a result of the above factors, a typical whole house water filter may not be able to remove manganese and thus not solve your black gunk problem. Consequently, it is likely the better and more affordable option to install an under-the-sink filtration system where you need it.

What does not permanently fix the problem?

When you google for terms like “how to get rid of the black gunk on faucets or toilet bowls” you will find a lot of suggestions of well-meaning folks that don’t work or that only temporarily solve the problem, including:

  • Regularly cleaning affected areas
  • Using chemicals or natural remedies to clean the affected areas
  • Flushing the main water supply line
  • Replacing pipes
  • Installing a whole house filter that does not rely on reverse osmosis

The root of the problem is particular minerals (manganese and iron) in your water supply. As a result, the only way to permanently address the issue is by removing said minerals from your water. One of the few ways to accomplish that is by reverse osmosis.

What causes black slime on bathroom fixtures?

Manganese-feeding bacteria (black slime) looks nasty, and I certainly don’t want to ingest it when taking a shower or taking a sip of water from the tap. But knowing that it is pretty much harmless gives me and my family peace of mind. Have you noticed manganese in your drinking water and if so, how did you get rid of it?

85 Responses to "Black slime on faucets? Learn what it is and how to get rid of it!"
  1. I’m about two hours drive to your west and we have similar issues with blackened fixtures, probably for the same reason. Thanks for mentioning that the plumbing may need occasional clearing.

    For your drinking water, almost any of the standard water filters should get rid of that bad taste. Google “water filter testing” for options. Just doing your drinking water is the cheapest method. I use a Brita filter in a water pitcher. The resulting water tastes fine, although apparent Brita isn’t that great for many other contaminates. The activated charcoal only improves the flavor. It is cheap though.

    Here is one source of research:


    Although they did not test for magnesium.

    • We usually only drink water from the dispenser built into our fridge. That’s filtered as well and tastes decent. We may consider installing a whole-house filter if the problem wasn’t solved by flushing the main line.

  2. Did flushing the main line help? I have the same problem in central Wisconsin. Yours was the only informative response of any search results on the web!

    • Hi Patrick! Unfortunately flushing the main line didn’t help. That means we have either too much manganese in the county water supply or it’s in the lines in our house. Now that I know it’s not a health but only a cosmetic issue I’m less worried about it though.

  3. We’ve been experiencing what resembles black mold the past couple of years in Michigan. It gets pretty ugly around the under rim of our toilets and where the water line is in the bowls and are constantly addressing the problem. Sometimes, I’ll soak some toilet paper with some ZEP from Home Depot and slap it on the affected areas like plaster of paris so there’s more of an opportunity for the chemical to do its thing instead of squirting it in the toilet and watching the majority of it drop down into the water inside the bowl where its least needed.
    It also accumulates at the faucet heads although I don’t recall seeing anything worrisome associated with the washing machine.
    We thought maybe it might somehow be related to our spending the winter months in Florida due to our turning the water off for long periods of time possibly allowing for growth of bacteria in the lines that never seems to go away upon our return and reuse. I’ve tried flushing the toilets with tanks full of bleach and while the problem disappears for a little while, it comes back. I’m planning on using some of the suggestions above and see if I can get to the truth of the matter and take a longer lasting and/or more permanent corrective course of action. I hope to be able to come back here and report the results.

    • Hey! Thank you so much. I’ve been having this problem for quite a while and had no idea where to find the answers. I hit the jack pot! Yours was the FIRST link a choose upon my google search. I need not look further .

    • It’s manganese. I called our city water. They admitted they don’t filter for iron or manganese (we have pink from the iron in our toilets too). Nearby cities have spent the money to filter for iron and manganese, but mine claims the water bill would need to go up significantly. Since the issue is “aesthetic” and not health negative, they said they haven’t felt the need to install a filter yet.

  4. Oddly enough I’m living in Alpharetta too, but in a brand new townhouse.

    I too have the manganese bacteria buildup. This must be a function of the water system itself. I also get the pink bacteria around the water line of my infrequently used toilets.

    Thanks for the local info!

  5. Interesting thread – I live in Sandy Springs, GA, also Fulton county in a new (2013) town home. I’ve been wondering about the black slime build-up as described above since we have the same issues. Oddly, our toilet cisterns are clear of the crud – I’d really have expected to see it there too. Black streaks in the toilet and faucet crud are vanquished by bleach, only to return. Looks like a whole house water filter may be the only solution.

  6. I bought a Brita water pitcher and a Pur filter for my faucet, same problem here in Ohio!
    Would you believe the “black gunk” forms on the spout of my filter too?
    Constantly cleaning toilets and showers too. I feel better about it after reading your article though, thank you for the info.

  7. A plumber installed a whole house water filter system because we were getting the black slime residue on everything the water touched. He identified it as you did…magnesium bacteria. Now the new system leaves tanish dusty and slimy residue on everything…this filter back flushes often but we stl get the tan dusty film and it does grow slime as well.

      • it was fabulously expensive to boot. We do live in Northern WI and have very acid soil….our well is at 50ft and we live on a lake….it’s a seep well….not an aquifer. He’s replaced the sandy substance (not sure what it is) twice and still everything is dull and dusty and slimy in the sink. so…not sure where to go from here….but at least we are rid of that disgusting black slimy goo! Thanks for your blog…first time I’ve found anything related to this black gooey stuff.

      • I live in Alvin Tx and also have a home water filtration system. I can’t say for certain but I did not notice the hunk until after I had it installed. It is somehow only on our rr faucets and one of the toilets. Very odd. Still trying m got get to the bottom of it. Thanks for posting it might not be harmful atleast I have that peace of mind.

        • I have the same problem with the black slime, it started after I installed a whole home water filter because the scaling was so bad it was ruining our faucets and dishes. Solved he scaling problem but gave us a new issue. Glad it’s harmless thanks for posting

    • LynnAnn, we have this slime problem in north GA as well and when we lived in Iowa we had a whole-house filter that ruined ALL of our dishes with that blasted powdery residue. It was awful. We tried everything to save our dishes but had to dispose of it all after we moved :( not worth it.

        • I’m in Signal Mountain Tennessee and we have the goop too. I didn’t get the whole house filter but for the drinking water and fridge (two spigots and the fridge). The company was AQUA-CLEAR or some such. We love the drinking water and the system cost about 2000 dollars. But the spigots still have the goop and the other comments seem to find downsides to the whole house system. I wonder if those have the reverse osmosis feature. Not that I know what that is but I paid extra for it and there is no powdery residue on the drinking water apparatus.

  8. Thank you for your research – I live just north of you in North Forsyth, we have the same problem, pink in the showers and black gunk on the faucets. So glad to hear it is not health issue.

  9. This issue also exists in Surf City, NC. The solution that we have come across is a whole house filtration system with an aerator. Most companies do not sell just the aerator when they prescribe a solution. This is an add on to the water softener and filter system and is installed before the filter.Just to note, if you are seeing pink stains, those are iron deposits. Black build up on the faucets is usually manganese. The aerator can assist with dealing with both of these issues, but do some savvy shopping and don’t get just one quote from a single vendor.

  10. We live in the northern U.P. and have a deep well at 72 feet that has never had this black stain and residue til a few years ago when we remodeled and built a new bathroom with PVC plumbing. Our toilet tank is completely black and the PVC piping in the basement has turned black. Very worrisome. Don’t know what to do? Our water tastes good and there is no staining in the sinks, shower, or washing machine. Just in the toilets and obviously in all our water lines.

      • Having the same problem in my Arkansas apartment.
        The PVC could be the source since I do not ever remember having this issue growing up. It was my chore to clean the bathrooms so surely I would have noticed it. Of course this was before the era of PVC piping.

  11. Im in CT and my kids toys in the bath get blackened after a week or so – Ive never noticed any bad taste or discoloration in the water itself (we dont drink the tap water anyway though-Brita) but the toilet tank – the sink drain – and the bathtub drains are caked in the black slimy stuff – i figured it was because the house was really old and i worry about health issues – but from what I’m reading lots of people having same problems even with newer plumbing – i wonder if PEX piping makes a difference? or is that just for the heating cooling and faucets and not for the drains?

    • I’m a licensed plumber and live in Charleston,Tn.. in a brand new house we just built.. It has pex piping.. It is driving me crazy.. I haven’t put a filtration system on yet but I plan on it.. I am on city water. I am also the only house on my dead end st.. It’s a new subdivision also.. Most of the whole home filters mainly filter sediment. Pay attn to the type of filter you buy.. if it isn’t made specifically for your problem it really won’t help anything.. I would also suggest flushing your water heater 2-3 times a year. Because it is basically a huge canister(like the housing your filter sits in) except it doesn’t have a filter in it. So it will catch and trap all the trash from your water. If you have a tankless water heater I would flush it every other month.. good luck. Also they are easy to flush. Standard and tankless. So don’t waste your money on a plumber unless it’s just once to learn how they do it..

  12. I live in the UK and have had this ongoing problem over 6 years or more. I firmly believe it’s something added to our water supply by the local Water Board. During the past 6 years I have lived previously in a bungalow and now a house but still have this black ‘gunk’, when I flush the toilets and it collects round the cold water tap and shower heads

  13. Thanks for a solution to something that we’ve been searching for —for years! We live in Alpharetta as well (brand new 4 year old house) and used to live in Cobb county. I don’t know what the difference is in the counties systems but we never had this issue in Cobb. We had our line flushed and it didn’t help and a plumber come out but he just suggested cleaning more often. We clean all of the faucets, etc. every two weeks and it always needs cleaning. My kids won’t drink tap water, even with the filter on our fridge. (and yes- we do seem to get black slime on the spigot of that too) I’m thinking of getting a water cooler. Any thoughts on that? Seems silly with a brand new house but…nice to drink water without slime worry.

  14. Thanks for the great info. I live in Southport, NC, which is basically on the coast between Wilmington and Myrtle Beach. We have been experiencing this issue for years, and it seems to be getting worse. We have a well for our lawn sprinklers, and you can definitely tell we have iron and manganese in the water. Our cement driveway looks like Guinness and Killian’s got into a fight!
    But the water supply to the house is county water, and judging from everyone else’s comments, we have manganese in it as well. The black slime is in all our faucets, shower heads, toilets, and yes, even the spout on fridge that provides filtered water. Curiously enough, it hasn’t affected the washing machine. Plumbing seems to be mainly PVC with a few pieces of metal here and there. I noticed no one has mentioned any odor associated with this issue, but our bathroom sinks, well, they stink! I’ve used Plink, Drano, Liquid Plumber, concentrated Mr.Clean (not a good idea, by the way!), and the smell goes away for a bit, but it always comes back. Haven’t used bleach as I’m not sure what the eco ramifications are. I will definitely contact our public utilities and have the water tested. But as for manganese not being harmful, I think it depends on if you suffer from migraines or not. Certain heavy metals and minerals (manganese is both, apparently) have been linked to migraines. I am NOT a doctor OR scientist, and I am not stating this as fact. However, I do suffer from chronic migraines, and thanks to your article, Michael, I may have stumbled onto a possible cause, or at least a contributing factor. Holy cow!

  15. I clean my toilet every day but once a week give the toilets a good scrub around the rim also my taps. I am amazed at all the black gunk that collects. We live in North Wales and this is a new problem, it also collects in the washing machine. I only drink bottled water.

  16. Thanks, your detailed explanation about that nasty black gook was very helpful. I live in north east Ohio and have the same iisues with my faucets.. I scrub the faucets about every 60 days with CLR, it dissolves the stuff. I am glad to hear that the ick isn’t going to slowly poison me.

  17. Yes, I have the same exact problems too, here in DFW area of Texas! We didn’t have this in our previous house (it was a new house too) that we lived in for 10 years though. It was only the next town over from where we live now. The house we live in now is only 7 years old and we live here for 3 years now. I’m going to ask my neighbors if they have the same thing going on with their water.

  18. I have the exact same problem in Fulton county GA as well. All of my plumbing is barely three years old. Thanks for posting this.

  19. Any idea how I can tell the difference between maganese build up from black mold? I’ve lived in Michigan my whole life and we recently bought a house in a town called Clawson. I’ve lived in cities surrounding Clawson–Berkeley, Royal Oak, Troy–they all use the same water I would suspect but my house in Clawson, mainly in the bathroom, I have this black sludge building up on fixtures, toilets and inside the bath tub faucet. Something I’ve never seen before! The bathroom was “remodeled” by a previous homeowner with an acrylic shower liner over the tub. It also appears that they blocked up a former window (the house is brick). I’m just worried they cut corners, did the project incorrectly and we now have mold growing underneath this all.

    • Hi Ashley,

      To be sure you would need to get a specialist in who deals with mold removal. That being said, mold often has a fuzzy appearance but can also look like a stain if it’s growing on a wall or furniture. Its most common colors are black green, brown, or white. Mold can feel like cotton, leather, velvet, or sand paper. It usually gives off a musty or earthy odor.

    • i live in Novi, and have the sludge in my kitchen faucet only. I just went through a remodel . I had the sludge before and after. We recently had a water main break, maybe now it will go away. The water now doesn’t have as much of a chlorine taste.

    • I live in Ypsilanti. We’ve been having the pink and black slime problem in our current house since we moved in 9 years ago, mainly in the bathrooms. The toilets are the worst, however. I have found the black slime in the tub faucet, the pink staining in the bathtubs and shower. When clean the toilet jets, I find small black chunks of what I assume is manganese. Also get what looks like mold and mildew buildup in the toilet tank (which is a year old). This house was 4 years old when we bought it. When we first started seeing these problems, we added a whole house media filter, a whole-house sediment filter, trying every type of cartridge, and we added a water softener as well. None of it made a difference with the slime or stains. This house has Pvc pipes coming in and going out with copper to faucets. Our old house built in 1988 is 3 miles away and we never had these problems. They both get city water from the same supply. I’m at my wit’s end with this.

  20. We live in a row of townhomes in Montana and are experiencing this black crud for the past year or so. None of my immediate neighbors on either side of me have this problem. Could it be our water heater? It is SO disgusting – I hate even brushing my teeth or rinsing my mouth out. I’ve cleaned big clumps of it off the faucets and in and around the toilet bowl as well as the bathtub. Ewww. Not sure which direction to take now. Thanks for this information. It has been very helpful reading others’ experiences with this problem.

    • I wouldn’t spend money to get work done on the water heater. Reason being is that the problem exists in the cold side as well. Money will be removed from your wallet but not the goo from the pipes. I put a half cup of bleach in the toilet tanks every other month (clean bowl, turn water supply off and drain 1/2 tank to clear bowl, second half gets bleach and flush. leave water off for a bit to allow bleach to kill anything in the toilet lines in the rim. It’s just an added step in cleaning. Other than that, I use an old toothbrush to scrub the faucet aerators then drop in the bleach cup (before doing the toilet)…
      Your neighbors might be embarassed to say they have the problem, or haven’t seen it yet, (You can secretly pull off a sink aerator next time you’re visiting their bathroom to confirm)

  21. We live in Hall County and have the same manganese and iron issues. The manganese-feeding bacteria seems to be the biggest issue. Not sure how it can be the pipes, since our home is fairly new and we noticed these issues within the first year. I also have the issue in my new low water level washing machine. I have to wipe the black gunk off of the gasket at the top to prevent it dropping in on clothes. We have lived in newer homes in NC and FL over the past 40 years and have never experienced this problem.

  22. Hi Michael, thanks for your article. Your intro threw me because I live and work in the Alpharetta area and moved here from Salzburg! I’m born in US, but my wife and kids are from Salzburg. Anyone else you know in the area from there?
    Anyway, we have the black buildup as well. If I figure anything out I’ll be sure to post here.

    • Hi Chris,

      thanks for stopping by – what a funny coincidence! Unfortunately, I don’t know anyone else from Austria who lives in the area. There are plenty of Germans but then again, they are everywhere ;)

  23. Hi, I came across your site two years ago after we had just moved into our new construction home and discovered this black sludge forming around our bathroom faucets and building up in toilets/washing machine. Our cool water also has a horrible stench that dissipates after a few seconds of running. Has anyone else had smell associated with this black slime issue? We have contacted the city and had water tested and was suggested to flush lines and water heater with bleach but I’m wondering how much good that would do if the stench is coming from the cool water? Has anyone figured out cause and resolution of this issue?

    • A water softener must have a salt Tank connecting this will remove manganese , magnesium, calcium, lead, iron and gross alpha this is considered to be a a secondary contaminant according to the EPA safe drinking water act I live in the state of New Jersey

  24. I live in Sarasota, Fl and have the black gunk problem. It also accumulates in my Keurig water tank. I drink most of my water either from the filtered fridge water dispenser or bottled.

    • I think I have the answer…..as I have had the black slime on my bathroom faucets. My initial plan was to install a whole house filter, which I purchased from Culligan. This is primarily a filter for some particulates and chorine, and it flushes itself every week or so. However…we still have black slime. What I noticed was that some faucets had NO black slime (my laundry tub). But our Moen faucets in all of the bathrooms had it. What appears to be the root of the problem is that each faucet handle has 2 O rings, which deteriorate slightly over time. Although there is not a heavy dripping sound from the bathroom faucets, I noticed that all of them were moist all the time. So replacing the O rings (on mine there are two per faucet handle) will stop the water from accumulating at the faucet aerator. If there is no constant stream of water, then the bacteria would not be able to develop. BTW it is cheaper to buy a pack of O Rings, if you have Moen (each of their cartridges are $13 each, but a pack of O rings for the whole house would be $10.)

  25. If I am not wrong, then I think it is one of most common problems which is usually found in many homes. It is mainly due to the old metal impelled water line having hard or well water. Thus, if you want to eliminate this problem permanently, then you should either install water softener or replace all the old metal pipe lines with a new one. No doubt, it is tough task and requires lot of effort and experience for its effectual completion. So, we must take the help of a professional contractor who will do same job effortlessly. As it is a cheap fix, hence, we should never neglect it, otherwise it may become a costly hassle in near future.

  26. Thank you. We are moving to an older house in Phoenix–closed in June and came down to start moving in at the end of August. House empty for two months and upon arrival the toilets were coated with black slime–bowls and tanks. Never saw anything like it in Chicago. Now at least we know what it is. Still not sure what to do about it, but at least We’re not quite as freaked out as we were yesterday. Thank you. A plumber told us he had never seen it before and was probably a result of hard water, but not organic. Sorry, all you have to do is look at this gunk to know it’s alive and growing!

  27. I have the same issue in Powell Ohio, and it drives me crazy! I have to clean my faucets and toilets continuously. Thank you for the great information for I too have been worried about the health issue.

  28. Thank you for this information! Have the same problem in Durham, NC. Relieved, like you, that this is primarily a cosmetic issue. Will continue to stock up on the CLR – that stuff works like a charm!

  29. We have the same problem here in Oklahoma. The house is a little over 10 years old & there is black ring around toilets & bathroom sinks. I thought it was due to hard water. I previously lived in another city in a house that was built in the late 1930’s & never had this problem. Makes me wonder if it doesn’t have something to do with the type of plumbing pipes that are used in newer houses. Wish I could find a way to prevent it.

  30. Live in Amherst NH. Just moved from one side of town to another. Both homes had same water supplier. New home show the signs of manganese. Will call supplier Thanks for the great information.

  31. Own a 3 family house this black non slime crud only occurs on first floor shower and tub toilet sink on same line has nothing some appears on kitchen sink around Pur filter cartridge. Shower head also. First floor has separate water heater. Any suggestions ???

  32. I live in Benson, NC and this has been an issue for me for a couple of years but not until recently had I noticed that the gunk had collected under the bathroom faucet and in the toilet. It has always been in the pipes because I remember if the my kids dropped something in the sink I couldn’t stand putting my hand to grab it because of the black gunk that accumulates. My tub was stopped up, I didn’t know from what, but I decided to use the plunger and there was so much buildup gunk that came up amongst other things but the black gunk was unbelievable. My toilet usually has pink and black streaks. I have never drank the water here since moving here because I’m a firm believer that water should have no taste. I drink Deer Park and have a Brita filter on my faucet. I don’t like for my kids to put their mouths on the faucet now since I cleared all that gunk off of it. I’ve read it’s not harmful but the look of it got my skin to crawling and I’ve been bleaching everything even though I can’t stand it because it gives me headaches. It really seems weird that its doesn’t get any better with cleaning.

  33. Thanks for starting a dialog on this problem. We are in Augusta and have great water from the tests we’ve done. We have the same issue though only in our 3 year old pool house. It has PEX supply lines. Our main house has no problems and has all copper pipe. Copper is a natural retardant to bacteria so I am suspecting that the PEX is allowing this bacteria to clog our sink faucet and build up in the toilet.

  34. Very helpful info, thank you. Does anyone know what kind of “harmless bacteria” are involved? Asking because I’ve been ill ever since we moved into our house 4 years ago, and the doctors have determined I have a sensitivity to mold. I’ve done mold testing, which came back negative.

  35. Same problem here in CT. Dont remember having this until the low flow plumbing products came to market. I removed the aerators from all our sinks and no more black goop in the sinks. The shower heads can usually be taken apart to remove the reducers that limit flow as well to help. I would rather have a higher water bill then drink black mold..

  36. Thank you all for quashing my fears. The good news is ~ life just goes on. Use the Britta and just keep cleaning it off. ☺
    SE Wisconsin must have the same issues.

    • NE Wisconsin has the same issues too! It’s been a nightmare since we moved into our house 5 years ago. The water department is coming this week to test our water and we will determine our next steps after we get the results.

  37. Physician and water quality research chemist perspective: Elevated manganese in drinking water is dangerous. The development of guidelines ignored research and contained mathematical errors. See below. Showering in water with elevated manganese allows water droplets containing it to go directly to the brain via the olfactory bulb and the bloodstream via the lungs, bypassing the normal intestinal regulation. Most of the effects are neuro-behavioral. Poor cognitive development and impulse control are the result of early exposure during pregnancy and infancy. Increased fighting behavior was seen in animal studies. Manganese in hair samples correlates with violent criminal behavior in prisoners. It may be a co-factor in ALS and hereditary Parkinson’s disease. There’s a lot of data emerging on the topic. Levels in groundwater are particularly high in the NC Piedmont. If your water is black, get the levels checked, treat if high, and recheck to ensure that the problem is solved.

    • For more details, scroll to the part of the citation that says free text, click, and read the section on manganese. Note that black slime occurs at levels of 20 micrograms/L (ppb), lower than the suggested max of 50 ppb.

  38. Dr H., you’re scaring me! I live in colombia greater area in SC and my house was built in 2012 with city water and pvc pipping. I thought it was a nuisance only by reading previous posts. I have MS which causes same symptoms as some you mentioned. I don’t need any other health problems! I have a tankless hot water heater but notice sulpher smell and the gunk in cold water as well as hot, and in toilet. This is a horrible issue even without health risks and seems nobody had a cure. Anybody found permanent cure? Experienced illness? Water company or plumber made no suggestions? I’ve gotten stomachs flu type symptoms when drinking the water without filtering. Despite water being clear and odorless. Anybody else?

  39. I live in Barrow Cty, Ga, just north of Gwinnett and have the black gunk. I have lived in the County for 30 yrs. Had well water till 3 yrs ago, when we moved and now have city water. Never had it with the well water. But thanks to Michael, I now know what it is, and know we wont get sick, but still discusting! One thought added to all these comments: it seems to only show up in areas that stay damp even when not used frequently. The guy that said, change your O rings might have something. In addition to heavy gunk around toilet rims and airated faucets, the toilet that is not used frequently, but has a slow drip of water from the rim inside the bowl has a black streak at that spot. The faucets that stay wet all night (I test by putting a dry paper towel to them in the morning) have the gunk, the dry ones don’t have the gunk. The hand held shower head has gunk only on lower end of shower head, which stays damp when hanging in its holder. BTW, I also have pvc pipes. I may try removing all the airator screens from faucets that seem to hold moisture there.

  40. Ditto in Pensacola, Florida. Thanks for your research efforts so we know that while this is nasty looking we at least don’t need to call a HAZ-MAT team to save us. And we aren’t going to spend $$$$$ for a whole house water filter system.

    And, of course, given this is 2018, we’ll be lucky if the EPA survives, much less does anything to improve our water quality.

  41. In Buford ga here. New built home. Electric water heater. I was blaming the lower water pressure in my house for this. It’s nice to see this article and others having the same problem. It builds up every faucet and shower head in my house .. it’s more like it is in the water it seems sometimes, than just built up. Atleast that was my concern. After my drinking water in my new fridge and ice cubes from it had little black specks.
    I increased my water pressure hoping this would solve it for me. As the psi was around 50. I have it set to 75 now.

    I know whole home filtration system won’t work on this. But I am sure there are other options?

  42. When we remodeled, we installed low flow water faucets in all bathrooms. Empty-nesters that we are, only the master bathroom gets frequent use and is the only bathroom with the problem.

    My thought has been that the density of the layers of flow-restricting screens could be restricting airflow from drying out the faucet water pipe. So far we haven’t been able to unscrew a cap to remove screens due to design at end of faucet. The dampness stays 24/7/365 creating a great potential for slime.
    We don’t have the same problem with the shower head.

    (We have a Bawell Platinum so bring water to the bathroom for toothbrushing.)

  43. We have the same issues here in Northern California (near the Oregon border): black slime quickly building up under the toilet rim and in all the drains. The issues Dr H mentioned are frightening as we both already have autoimmune illnesses (CFS / ME and Environmental Illness) from exposure to chemicals where each of us used to work. We just recently got a Doulton water filter (it’s used by orgs like Doctors Without Borders) because none of the other filters on the market are good enough to remove all we need taken out of the water… We’re really happy with the Doulton, but now fretting about the water from the shower and faucets… If nothing works to manage the manganese-eating bacteria… wow…

    We moved here to get away from a place that grew pink-red fuzzy mold throughout the entire water system…

    I thinking now that there is no safe water anywhere here… I’ve talked with folks who’ve been studying water systems across the US, and their consensus was that we’re heading for a water crisis of epic proportions… that all we can do is the best we can…

  44. Does anyone know if the black slime that sits in your front loader rim is the same harmless bacteria or what type of bacteria it is?

  45. Water utilities use a phosphate blend to help with corrosion of pipes. The black slime on your aerators, shower heads and drains is a form of mold. It is not actually coming from the water supply but attracks to the water. When washing with soap, the phosphates in the soap is food for the bacteria (mold). Damp, dark and now food for the mold leads to the perfect environment for it to grow. The reason it comes back so often is because you have not killed the spore. Clean with bleach, white vinegar etc..must let it soak for a couple of minutes and then scrub. This should prolong it from coming back as fast. Also, try drying your fixtures after doing this and you will notice the problem will not re-occur due to there is not moisture for it to thrive on. The pink stains are also a form of bacteria (mold). This works the same as the other, it just leaves a pink residue but left un attended it will turn black. As far as the manganese, it will cause black staining on fixtures, especially on your porcelain toilet tanks. Depending on the water company’s treatment techniques this should mostly be taken care of at the water treatment facility. Phosphate will help sequester the iron/manganese. Hopefully this will help. But whenever in doubt call the water utility and have it tested.

  46. I have been able to get rid of the black gunk in faucets and under the toilet rim by using a steamer. For the toilet, point the steamer attachment into the holes under the rim. It takes a while,but the stuff eventually loosens and can be flushed out. It wil last 1-2 weeks before it comes back, which is much longer than when using toilet bowl cleaner or bleach.

  47. Good information about the black slime coming out of faucet. Thanks this was very helpful. Glad to know it’s not a health threat.

  48. Same problem here in Berea Kentucky but only since we moved from a house with city water to a house with county water. Thank you for the reassurance that the black gunk and brown stains are not mold! We drink filtered water but still hate the idea of gunk in our showers and sinks. I have never liked using Clorox but now I’m constantly using it on faucets, shower heads, drains and in the toilets. Whole house filtration sounds like a better idea. Hope it also works on the hard white scale in our water.

  49. I live in an apartment and have terribly hard water. Black gunk is constantly coming out of the bathroom faucets and even in the washer/dryer . Is there a way to get rid of it? I’m not going to be doing any work on this since I’m renting but I didn’t know how to clean it or what to tell the apartment complex people to do. It’s so disgusting!

  50. Are you certain it is not mold or a health threat? My daughter has developed terrible allergy-type health issues that her doctor said may be related to mold exposure. Her bathroom has developed black gunk (mold?) building up around her faucet spout and the edges of her undermounted lavatory where it meets the countertop. Looks like mold to my inexperienced eye.

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