Report No DWI0088

Mar 1981


  1. This report gives details of an investigation into the contamination of potable water by lead arising from the corrosion of soldered joints.

    The work was undertaken as part of a contract from the Department of the Environment to investigate the potential of materials used in plumbing systems to contaminate the supply.

  2. Because of the galvanic stimulation of the corrosion, it was found that even small areas of solder, exposed in the bore of the tube, could be expected to produce unacceptably high levels of lead given sufficient residence time of the water in the pipe.

  3. The recommendations of this report are:

    1. leaded solders should be prohibited for use in systems carrying potable water. To effectively enforce this ban it would be necessary to insist that either no joints can be made with leaded solders (which would include those in central heating systems), or that only compression fittings can be used in potable water systems.

    2. the detailed description on how to make a soldered joint, given in Copper Development Association publication TN22 should be more widely publicised (See Appendix VIII)

    3. regular flushing of new plumbing systems, to reduce contamination problems from materials of construction, including where used leaded solder joints should be encouraged.

Copies of this report may be available as an Acrobat pdf download under the 'Find Completed Research' heading on the DWI website.