Manganese in well water
Manganese dissolves into well water from rock and soil. Above 0.05 mg/L it leaves black stains and a bitter taste. Above the EPA's health advisory of 0.3 mg/L, it's a concern for the brain and nerves, and babies are the most sensitive. A water softener or an oxidizing filter removes it.
If you buy something through our links, we may earn a commission. We'd recommend the same thing either way, and we'll tell you when a free option exists. How we make money
What you need to know about manganese
| The health advisory | 0.3 mg/L (milligrams per liter, the same as 300 µg/L) for lifetime drinking. The EPA says babies under 6 months shouldn't drink water over 0.3 mg/L even for 10 days. |
|---|---|
| The stain and taste level | 0.05 mg/L, the EPA's secondary standard. It's a guideline for black stains and taste, not a health limit. |
| Who it hurts | Babies are the most sensitive. Years of high levels may affect memory, attention and motor skills in children and adults. |
| Where it comes from | Natural rock and soil, mostly in groundwater low in oxygen. It's common in the glacial aquifers across the northern states. |
| How often to test | At least once, and before a baby drinks the water. Iowa suggests every 3 years. |
| What removes it | A water softener for small amounts, an oxidizing filter for moderate levels, or chlorine followed by a filter for high levels. |
These counties see the most manganese in their wells
Ranked by the share of tested wells with a result over the limit. We only list counties with at least 25 tested wells, so a few bad results can't skew the ranking.
| County | Wells tested | Wells over the limit |
|---|---|---|
| Washington County, MS | 32 | |
| Lonoke County, AR | 28 | |
| Jackson County, MO | 55 | |
| Washington County, OR | 27 | |
| Monroe County, AR | 43 | |
| Nobles County, MN | 68 | |
| Multnomah County, OR | 46 | |
| Lancaster County, NE | 31 | |
| New York County, NY | 25 | |
| Washington County, NE | 44 |
* Likely overstated, because of who tested these wells, when or where.
See the full rankings and download the data
Manganese dissolves from rock into water with little oxygen
Manganese is a natural metal in rock and soil. Groundwater that's low in oxygen dissolves it, and Penn State Extension says it's more common in deeper wells, where water has sat against rock longer. It often shows up with iron, usually at lower levels.
It's widespread. In a national USGS study, about 23% of wells in drinking-water aquifers were over the 0.05 mg/L stain level, and about 7% were over 0.3 mg/L. The glacial aquifers that stretch across the northern states had manganese at levels of possible health concern in more than 10% of wells sampled.
Levels change from place to place. The Minnesota Department of Health says southeastern Minnesota tends to be under 0.05 mg/L, while some wells in southwestern Minnesota are over 1 mg/L.
Babies are the most sensitive to it
Your body needs some manganese, and most of it comes from food. Minnesota says the body absorbs manganese from water more easily than from food.
Too much over a long time is a concern for the brain and nerves. Minnesota says children and adults who drink high levels for years may have trouble with memory, attention and motor skills, and babies may develop learning and behavior problems.
The EPA set a lifetime health advisory of 0.3 mg/L to protect against these effects. Babies absorb more manganese and clear less of it, so the EPA advises that infants under 6 months not drink water over 0.3 mg/L even for 10 days. Minnesota goes further: if a baby drinks tap water or formula made with it, it advises 0.1 mg/L or less.
Bathing and showering in it are fine. Minnesota says high manganese is a concern only in water you drink.
Test for it even if the water looks clear
Dissolved manganese can come out of the tap clear and then turn into black specks or stains once it meets air. Penn State says a test should report both the amount and whether it's dissolved or already solid, because that decides the treatment.
Test at least once, and before a baby starts drinking the water. Ask a certified lab for manganese and iron together.
Some states test for free. Iowa's Private Well Grants program covers manganese, along with bacteria, nitrate and arsenic, and suggests a manganese test every 3 years.
If you already have a softener or filter, Minnesota notes it may lower the level at your tap. Test before and after the treatment to know what you're drinking.
A softener or oxidizing filter takes most of it out
Manganese stains and taste affect all the water in the house, so Penn State recommends treating it where it enters. Which system fits depends on how much iron and manganese you have together, and on your water's pH.
| Option | When it fits | Typical equipment cost | Things to know |
|---|---|---|---|
| Water softener | Small amounts of dissolved manganese; pH over 6.7 and dissolved iron under 5 mg/L | $500 to $1,500 | A Minnesota study in Dakota County found softeners can be effective for manganese |
| Greensand oxidizing filter | Iron and manganese together at 3 to 10 mg/L | $500 to $1,500 | Needs regular backwashing and potassium permanganate, which must be handled carefully |
| Birm filter | Water with enough oxygen and pH of at least 7.5 | $500 to $1,500 | Penn State says manganese removal with birm is highly variable |
| Chlorine plus a filter | Iron and manganese together over 10 mg/L | Ask for quotes | Needs a chemical feed pump and steady upkeep |
Costs are equipment ranges from Penn State Extension.
Polyphosphate feeders, which hold iron in solution to stop stains, generally don't work on manganese, according to Penn State.
Questions people ask about manganese
Is it OK to bathe in water with high manganese?
Yes. The Minnesota Department of Health says bathing or showering in water above its guidance level isn't harmful. The concern is drinking it.
What causes black stains in my toilet and sink?
Usually manganese. The EPA says it causes black to brown water, black staining and a bitter metallic taste above 0.05 mg/L. See our page on black specks.
Can I use my well water for baby formula?
Test it first. The EPA advises keeping babies under 6 months off water over 0.3 mg/L. Minnesota advises 0.1 mg/L or less for any baby who drinks tap water or formula made with it.
Does a water softener remove manganese?
It can. A Minnesota Department of Health study in Dakota County found softeners can be an effective way to lower manganese. Penn State says manganese that has already turned to solid particles fouls the resin, and an oxidizing filter handles that better.
Where this comes from
- U.S. EPA, Drinking Water Health Advisory for Manganese (2004)
- U.S. EPA, Secondary Drinking Water Standards
- Minnesota Department of Health, Manganese in Drinking Water
- Penn State Extension, Iron and Manganese in Private Water Systems
- Penn State Extension, Tips for Buying Water Treatment Equipment
- USGS Circular 1360, Water Quality in Principal Aquifers of the United States, 1991 to 2010
- Iowa DNR, Private Well Testing