UK legal limit: 50 µg/L. Find out what manganese is, its health effects, and how to check and reduce it in your tap water.
Free · Instant · No sign-up
Manganese is a naturally occurring metal found in soil and rock formations. It dissolves into groundwater and surface water, and can also enter tap water from the corrosion of ageing iron and manganese deposits in distribution mains. At elevated concentrations, manganese causes the most visible water quality complaint in the UK: black or brown discolouration, particularly noticeable after a period of low demand or after water main disturbance. The UK legal limit for manganese in drinking water is 50 µg/L.
UK compliance rates for manganese are generally good — over 99.5% of samples pass the legal limit. However, manganese is one of the more common parameters to occasionally exceed, particularly in groundwater-sourced zones and older distribution networks. Zones served by borehole sources in the East Midlands, East of England, and parts of Southern England can see higher manganese levels.
Manganese is an essential trace element — the body requires small amounts for enzyme function. However, at elevated long-term exposure, manganese can accumulate in the brain and cause neurological effects. Research published in the last decade has identified associations between elevated manganese exposure (typically via drinking water above 100–300 µg/L) and cognitive development effects in children, Parkinsonism-like neurological symptoms at very high occupational exposures, and reduced IQ scores in children exposed to high-manganese well water in studies from North America and Asia.
The WHO has a health-based guideline of 400 µg/L for adults — far above UK limits — but recommends more protective limits for infant formula preparation. The UK legal limit of 50 µg/L is set with a significant safety margin. At typical UK concentrations (usually below 20 µg/L), neurological effects from drinking water alone have not been demonstrated.
If you see black particles or brown discolouration in your tap water, this is often manganese or iron deposits disturbed from pipe walls. Run the tap until the water runs clear and report the issue to your water company. Do not drink visibly discoloured water until it clears. Persistent discolouration should be reported — your water company is obliged to investigate.
This page contains affiliate links. We may earn a commission if you purchase — at no extra cost to you.
Black particles in tap water are often manganese or iron deposits from the inside of water mains, disturbed by pressure changes or nearby work. Run the tap until clear and report to your water company if the problem persists.
At UK legal limit concentrations (50 µg/L), manganese in tap water is not associated with health risks for adults. Health concerns from manganese relate to sustained exposure at much higher concentrations, particularly for infants and children.
The UK legal limit for manganese is 50 µg/L. Most UK zones achieve levels well below this.
Groundwater-sourced zones in the East Midlands, East of England, and parts of Southern England tend to have higher manganese. Areas with old iron mains can also see manganese from pipe corrosion.
Greensand filters (iron/manganese media) are designed to remove dissolved manganese. Reverse osmosis also removes manganese. Standard jug filters have limited effectiveness for manganese removal.
Run the tap until clear. If the problem persists, contact your water company. Avoid drinking persistently discoloured water. Your water company must investigate and resolve the cause.