You turn on the shower and… there are tiny black flecks in the water. Or you notice black specks on the tub after the water drains. Annoying? Yes. Immediately terrifying? Usually no — but it is worth figuring out what you’re looking at.
The good news: black bits in shower water typically come from a small set of common causes, and most of them are fixable without a full plumbing saga.
First: what do the black bits look and feel like?
This quick “ID check” saves you a ton of time:
A) Dusty / pepper-like specks (smudge when rubbed)
Often points to carbon fines (tiny carbon particles), especially if you’ve recently changed a filter or cartridge. Appliance manufacturers commonly note this can happen with new filters and is typically resolved by flushing.
B) Rubbery bits (soft, squishy, gasket-like)
Often points to a deteriorating rubber washer / gasket / hose lining somewhere in the plumbing path.
C) Black staining or dark residue that builds up
Can be linked to manganese in water (it can cause black/brown staining on fixtures and in bathrooms). UK water companies explicitly mention manganese as a cause of black water/particles.
D) Only happens with hot water
That pattern often points to the water heater (sediment/corrosion/anode issues can shed particles into hot water).
The most common causes (from most “likely” to “check this”)
1) Manganese stirred up in the water supply or pipework
Water companies in the UK commonly explain that naturally occurring manganese can cause black water or black particles — sometimes after a disturbance like main repairs or a burst main that stirs up sediment.
Public health guidance also notes manganese can leave brownish-black/black staining on bathroom fixtures.
What it looks like: dark staining, dark particles, sometimes discolouration that comes and goes.
What to do:
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Run the cold tap for a bit (often it clears as the disturbance passes).
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Avoid washing light laundry until it clears (manganese can stain).
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If it persists or is widespread, contact your water supplier and ask if there were network works in your area.
2) Carbon fines after installing or changing a filter
If the specks appeared right after a new filter/cartridge, there’s a strong chance it’s just fine carbon particles that need flushing. GE’s support guidance for water filters specifically says black particles after install can be leftover carbon and recommends flushing several gallons.
What it looks like: tiny black “pepper” that may smear gray/black on tissue.
What to do:
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Remove your showerhead and run water through the line for a minute (reduces clogging in the head).
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Then reinstall and run the shower for a few minutes.
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If you have a filter, follow its flushing instructions carefully (many require an initial flush).
3) A degrading rubber washer, gasket, or hose lining
Rubbery black specks are often a plumbing “wear and tear” thing: washers/gaskets can break down and release particles.
Some water suppliers even mention broken washers as a cause of black particles.
What it looks like: squishy bits, sometimes irregular chunks rather than dust.
What to do (easy mode):
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Unscrew the showerhead and check the little rubber washer inside. Replace if cracked or degraded.
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If you have a handheld shower hose, check/replace it (inner linings can shed over time).
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If particles continue, a plumber can check other washers/gaskets upstream.
4) Water heater issues (if it’s mostly hot water)
If black specks appear only in hot water, your water heater may be the source (corrosion/sediment/anode rod deterioration can release particles).
What to do:
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Test: run cold water in the same bathroom tap into a clear glass → then run hot. Compare.
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If hot-only: consider a heater inspection/flush, and ask about the anode rod (especially if the heater is older).
A simple troubleshooting path (10 minutes)
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Does it happen only with hot water?
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Yes → look at the water heater.
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No → continue.
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Did it start right after changing/installing a filter?
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Yes → flush (carbon fines are common early on).
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No → continue.
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Do the particles feel rubbery?
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Yes → check/replace washers, hoses, gaskets.
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No → continue.
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Any black/brown staining on fixtures or discoloured water episodes?
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Yes → manganese is a strong candidate; water supplier pages explicitly mention it.
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Still unsure or it’s getting worse?
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Ask your water supplier if there were local works, and consider a basic water test (especially if staining persists).
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Is it dangerous?
Often, it’s more of a nuisance than a danger — but it depends on the cause.
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Carbon fines are widely treated as a harmless byproduct that clears with flushing.
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Manganese: health agencies note that showering/bathing in manganese-containing water is not the same risk as ingesting high levels, but it can cause noticeable staining and aesthetic issues.
If you’re immunocompromised, if the water smells unusual, or if discolouration is persistent and widespread, it’s reasonable to contact your supplier and/or do a formal test.
Quick “what to do right now” checklist
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✅ Wipe a speck on white tissue (dusty vs rubbery)
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✅ Compare hot vs cold
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✅ If new filter: flush a few minutes (per instructions)
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✅ Check the showerhead washer + hose
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✅ If staining/discolouration: check supplier notices / contact them