The dangers of lead solder

watersafeSince the 1980s, use of lead solder for jointing copper pipes has been prohibited for plumbing systems supplying wholesome water for drinking, cooking or bathing.

Under the Water Fittings Regulations, solder containing lead can be used only on non-drinking water installations where the water is not required to be wholesome, such as closed circuit central heating systems.

Despite this, UK water suppliers still find examples of recent installations where lead solders have been used illegally. In 2013, the Drinking Water Inspectorate received reports from water suppliers of 11 routine drinking water quality check samples exceeding the permitted amount of lead. In a recently-built luxury apartment block investigated by one water supplier, tap water samples contained more than 12 times the permitted amount of lead. Five or six joints on short lengths of distribution pipe entering each apartment had been made using solder containing lead. Enforcement notices under the Water Fittings Regulations required the developer to replace every suspect joint – at his own cost.

Most people know lead is a dangerous metal which can cause serious poisoning if too much enters the body. It has been banned in petrol, paint and plastics and to reduce human exposure via drinking water, at the end of 2013 the permitted maximum was further reduced by 60% to ten micrograms per litre (one part in 100 million). Using lead-free solder isn’t just a legal requirement, it safeguards customers’ health. In another incident, a little boy and his father suffered from lead poisoning which was directly attributable to the illegal use of leaded solder.

Workman-like manner and the AIM

If you install or use any plumbing systems or plumbing fittings which are to take water from the public water supply, you must follow the requirements of the Water Fittings Regulations. These requirements include the stipulation that all installations must be carried out in a ‘workmanlike manner’. One of the ways to ensure you do this is to follow an Approved Installation Method (AIM). There’s an AIM available for using solder and fluxes, available free from the WRAS website: Approved Installation Method leaflet ‘Solders & Fluxes No. 9-04-02′ ( – under ‘Consumers’ click on ‘Resources’, then ‘Publications’.)

Where the illegal use of lead based solder is found by water suppliers who enforce the Water Fittings Regulations, they will require the installation to be cleared of all joints containing lead solder at the installer’s cost. The installer may also face a criminal prosecution for not complying with the Regulations.

Using lead-free solder

Lead free solder such as Number 23, Tin/Copper Alloy Soft Solder made to BS EN ISO 9453 with a melting point of 230˚C to 240˚C will satisfy the requirements of the Regulations. Lead-free solders have a higher melting point than traditional leaded solders; the higher temperature causes old-style fluxes to burn or char before the solder melts, leaving carbon deposits in the pipe which can accelerate corrosion. So when working with lead-free solder you need to choose an appropriate flux. Water soluble fluxes are preferred because they are more easily cleaned from pipework after use than grease based fluxes.

Installation tips can be found in the comprehensive ‘Installation Tips – Fluxes and Solders’ on the from the UK Copper Board website,

Previous articleBaxi announces new partnership with Nest
Next articleWaterSafe agrees ‘keep it simple’…

No posts to display