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PEHSU Factsheet on Lead and Drinking Water: Information for Health Professionals Across the United States (2016) > What factors affect how much lead gets into drinking water?

What factors affect how much lead gets into drinking water?

posted on Aug 1, 2019
Type of plumbing materials:
  • Homes built before 1986 are more likely to have pipes, fixtures, or solder that contain lead. Newer homes may also present a risk: until recently, approved “lead-free” plumbing fixtures may have contained up to 8% lead. As of January 2014, changes to the Safe Drinking Water Act have further reduced the maximum allowable lead content of pipes, pipe fittings, and plumbing fittings to 0.25%.
  • Lead can be included in plumbing materials from the water service main to the property line and/or to the internal household plumbing (Figure 1).
  • Families can identify if they have a lead service line by inspecting their own plumbing, hiring a plumber, or calling their water provider. Lead service lines are generally a dull gray color that are very soft and are easily scratched with a key.
  • Construction and repair work on supply and distribution lines can increase water lead content.
  • Corrosiveness of water: Lead can enter drinking water through corrosion of plumbing materials, especially where the water has high acidity or low mineral content.
  • Length of time water stands in pipes: Lead can build up in tap water when water stands in the pipes for an extended duration, such as for six hours or longer.