What it is
Arsenic is a natural element found in many minerals. It has no taste or smell in water and is detected only by laboratory testing.
Where it comes from
In the UK arsenic in private supplies comes mainly from natural minerals in the aquifer, particularly in some sandstone and mineralised areas, and occasionally from old industrial or mining activity and historic pesticide use.
Why it matters
Long-term exposure to arsenic above the guideline is linked to skin changes and an increased risk of several cancers, which is why the guideline is set low and a result over it is taken seriously, even though there is no immediate danger from a single glass.
What can be done about it
Arsenic is removed by specialist adsorption media (iron-based filters) or by reverse osmosis. Treatment is sized to the result and the form of arsenic present, and a retest confirms the water is clear. A Pozzani engineer will advise on which suits the supply.
Information last reviewed 5 October 2026 by Pozzani Pure Water.