What it is
Copper is the metal most household pipework is made from. Small amounts dissolve into water that stands in the pipes, and more dissolves when the water is soft, acidic or warm.
Where it comes from
Almost all copper in drinking water comes from the property's own pipework and cylinders, not from the source. New copper pipe releases more until a protective layer forms inside it. Low pH water, common from upland and peaty private supplies, is the usual reason for high copper.
Why it matters
Copper is an essential nutrient, but too much causes stomach upset, and long-term high intake can affect the liver in sensitive people. The guideline protects against that with a wide margin. Below it, the signs are blue-green stains on baths and basins and a metallic taste.
What can be done about it
Correcting a low pH with a neutralising filter is the usual answer, because it stops the water attacking the pipe in the first place. Running the tap to clear standing water before drinking helps in the short term. Where pipework is badly corroded, replacement is the long-term fix.
Information last reviewed 5 October 2026 by Pozzani Pure Water.