Copper water pipes can corrode for several reasons, including age, the chemistry of the water inside them and what touches them on the outside. Leftover soldering flux, contact with other metals and damp building materials can also play a part. Copper is a hard-wearing material, so corrosion is often slow, but it can still lead to leaks over time.
Corrosion From the Inside
Age is one of the most common factors. After many years in service, the inside wall of a copper pipe can slowly wear in places. Water flowing quickly through small bends or fittings may add to this wear.
Water chemistry can also matter. In general terms, things like how acidic or alkaline water is, and what minerals it carries, can affect how copper behaves over time. This varies from place to place and even between properties, so it is not something to guess at from home.
Flux residue is another possible cause. Flux is a paste used when soldering copper joints. If too much is used and it is not flushed out afterwards, small amounts left inside the pipe may slowly attack the copper near the joint. This is one reason joints can be a weak spot.
Corrosion From the Outside
Copper can also corrode from the outside. Contact with a different metal, such as old steel or iron, can cause what is called galvanic corrosion, where one metal wears faster because of the contact. This is sometimes seen where older and newer pipework meet.
Damp is another common cause. Pipes buried in cement floors, set into plaster or sitting against wet brickwork can be affected by moisture and by chemicals in those materials. Pipes under floors near a long-term leak may also show outside corrosion.
Signs of Corroded Copper Pipes
The most familiar sign is green or blue staining on the pipe, especially around joints. You may also see crusty build-up or dark patches. Blue-green marks on sinks, baths or tiles below a tap can sometimes be linked to copper in the water, though they can have other causes too.
Pinhole leaks are a more serious sign. These are tiny holes that may only weep or spray a fine mist at first, and they are not always easy to spot. Damp patches, water stains on ceilings or a musty smell can be clues. A single stain does not always mean the whole system is corroded, so it is best to have it looked at.
Why a Professional Assessment Helps
Corrosion in one spot does not always mean every pipe needs changing. A plumber can check how widespread the problem is, whether joints need remaking and whether a short section should be replaced. For copper pipe repair and replacement, an inspection helps you avoid both unnecessary work and repeated leaks.
If you have noticed green staining or small leaks on copper pipes at home, Emergency Plumber Swindon can help you work out what is going on. Call us on 01793 569521 to talk it through.