UK legal limit: 200 µg/L. Find out what aluminium is, its health effects, and how to check and reduce it in your tap water.
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Aluminium is used extensively in UK water treatment as a coagulant — aluminium sulphate (alum) or polyaluminium chloride (PAC) is added to raw water to cause suspended particles, organic matter, and microorganisms to clump together (flocculate), allowing them to be removed by sedimentation and filtration. When treatment is working correctly, virtually all the aluminium added is removed along with the particles it was meant to capture. The residual aluminium in treated water is typically very low — below 20 µg/L in most cases.
The UK legal limit for aluminium in drinking water is 200 µg/L. This limit is aesthetic rather than health-based — at concentrations above 200 µg/L, aluminium can cause visible discolouration (white milkiness or floc) and is a sign that coagulation treatment is not working optimally. Compliance is generally very high across the UK.
This is the question most people ask about aluminium in water. The short answer is: there is no convincing evidence that aluminium in tap water causes Alzheimer's disease. The hypothesis was proposed in the 1980s based on the observation that aluminium accumulates in the brains of Alzheimer's patients — but subsequent research has not established a causal link. The Alzheimer's Society, WHO, and UK water regulators are clear that aluminium in drinking water at concentrations found in the UK is not a risk factor for Alzheimer's disease.
Aluminium occurs naturally in food — it is the third most abundant element in the Earth's crust. Daily intake from food (antacids, baked goods, tea, processed foods) typically dwarfs any contribution from tap water.
Elevated aluminium in tap water is primarily a process control issue — it indicates that coagulation treatment was not fully effective. Events of elevated aluminium can follow sudden changes in source water quality (after heavy rainfall, algal blooms) when treatment parameters need rapid adjustment. Water companies monitor aluminium continuously and treat elevated readings as an operational alert.
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No. Despite the hypothesis raised in the 1980s, there is no convincing evidence that aluminium in tap water at UK concentrations causes Alzheimer's disease. The Alzheimer's Society and WHO are clear on this point.
Aluminium sulphate or polyaluminium chloride is added to water during treatment as a coagulant — to remove particles, organic matter, and microorganisms. Residual aluminium after treatment is usually very low.
The UK legal limit for aluminium is 200 µg/L. This limit is primarily aesthetic — at this concentration, aluminium can cause visible cloudiness. Most UK zones achieve much lower levels.
At UK tap water concentrations, aluminium is not considered a health risk by the WHO or UK regulators. Daily intake from food (tea, baked goods, antacids) typically far exceeds any contribution from tap water.
Reverse osmosis removes dissolved aluminium effectively. Activated carbon block filters have moderate effectiveness. Standard GAC jug filters are less effective.
White cloudiness from the tap is usually dissolved air (harmless, clears bottom-up within 60 seconds) or, more rarely, elevated aluminium from treatment issues. If white cloudiness persists or doesn't clear, contact your water company.