Lead is hazardous to human health and the main sources of exposure are: lead based paint, lead contaminated dust or soil, and some plumbing materials such as lead service lines, solder, and brass fittings.
In 2017, NOCO Engineering Company worked with a local water district that was out of compliance for lead levels in their water. Lead had never been detected in their raw water source and the distribution system had no known lead service lines. The only known plumbing components containing lead were:
When water is in contact for several hours with pipes or plumbing that contain lead, the lead leaches into the drinking water. The EPA requires that the purveyor of the water reduce the likelihood of this occurring.
Water treatment has a "Domino Effect"; when you address one issue it can affect another issue. Finding the correct treatment method to meet all of the water quality parameters is challenging. Utilizing research from Virginia Tech, NOCO Engineering worked with the water district to establish a process to limit the amount of lead leached into the water while maintaining other water quality parameters. Testing 60 data points in their system, the water district was able to lower their lead levels from an average of 13 ppb (parts per billion) to 7 ppb in only three months and down to 2.7 ppb in six months.