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Black Specks or Black Water in Well Water: Manganese and What to Do

Updated November 1, 2026 · General information, not medical or plumbing advice

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What manganese looks like

• Clear, then dark. Pennsylvania's health department says water containing manganese might appear colorless at first, but black stains or particles quickly appear as the manganese is exposed to oxygen. Penn State Extension says dissolved manganese is most common in groundwater with a pH below 7.0.
• Black particles. Connecticut says the particle form makes water look black or leaves black particles that settle out.
• Stains. Connecticut says manganese may cause brown-black staining. Soaps and detergents will not remove it, and chlorine bleach may make it worse. Pennsylvania says it can stain laundry and sinks.
• Metallic taste. Pennsylvania says manganese causes a strong metallic taste, and that iron and manganese often occur together, which can increase the taste and discoloration.
• Equipment. Connecticut says deposits can build up in pressure tanks, water heaters and softeners, reducing their effectiveness and water pressure.

The pages we opened cover manganese only. They do not say what else can make black specks, such as worn plumbing parts or filter media, so a lab test and a look at your equipment come first. For iron's orange stains, see iron in well water.

Is it a health problem?

• Taste and stain level. Pennsylvania and Connecticut both give 0.05 mg/L as the EPA's recommended (aesthetic) limit. Both say it is based on taste, color and odor, not health.
• Health advisory level. Pennsylvania says to avoid drinking water above 0.3 mg/L over a long period. Connecticut's action level for private well water is also 0.3 mg/L. Penn State Extension says the EPA's 0.3 mg/L health advisory is non-enforceable and was set over concerns about neurological effects from regularly consuming water above it.
• Higher levels. Pennsylvania says if manganese is above 1 mg/L, its health department advises against using the water for drinking or cooking.
• Babies. Pennsylvania says babies under six months should never drink water or formula made with water above 0.3 mg/L, and that it is best for them to have water below 0.1 mg/L. Connecticut says infants absorb more manganese and excrete less, and recommends pregnant women and young children drink water below 0.3 mg/L.
• Showering. Pennsylvania says manganese does not go into the air and is not taken in through the skin, so bathing and washing dishes and clothes remain safe.

What to do

1. Test at a state-certified lab. Connecticut says home test kits may not provide accurate results. It says to identify the form of the manganese if possible, because the results help decide treatment. Penn State Extension says concentration and form determine the treatment choice.
2. Protect babies in the meantime. Use bottled water for formula until you have results (our suggestion, based on the infant guidance above).
3. Match treatment to the lab report. Connecticut says solid manganese is typically handled with a particle filter, and lists oxidizing filters, ion exchange, aeration with filtration and chemical oxidation with filtration. Penn State Extension says phosphate addition is generally ineffective for manganese and that chlorine is not recommended as an oxidant for very high manganese. A licensed water treatment professional can size a system.

Common questions

Why is there black stuff in my well water?

One common cause is manganese. Connecticut's health department says manganese in its particle form makes water look black or leaves black particles that settle out, and that dissolved manganese looks clear at first and then turns black when exposed to air. The pages we opened cover manganese only, so a lab test is how you confirm the cause.

Is black manganese in water dangerous?

It depends on the amount and who is drinking it. Pennsylvania's health department says manganese above 0.05 mg/L is unlikely to harm health. It advises avoiding long-term drinking of water above 0.3 mg/L, and says babies under six months should never drink water or formula made with water above 0.3 mg/L.

Is it safe to shower in water with manganese?

Pennsylvania's health department says manganese does not go into the air and is not taken in through the skin, so showering, bathing and washing dishes or clothes is still safe even if the level is too high for drinking. It also says water above 1 mg/L should not be used for drinking or cooking.

How do I test for manganese?

Connecticut says to use a state-approved laboratory certified to test drinking water, and that home test kits may not provide accurate results. Penn State Extension says concentration and form determine the treatment choice. Ask the lab to report both.

Will bleach or soap remove the stains?

Connecticut says soaps and detergents will not remove manganese stains, and chlorine bleach may make them worse.

Related guides

• Iron in well water: orange stains and fixes
• Well water testing: what, when and how often
• What's wrong with my well water? (checker)