What is lead and why are we working to keep it out of drinking water?

Lead is a naturally occurring element that humans have been mining and using in all sorts of products for thousands of years. High doses of lead have been known and accepted as toxic to humans for a long time, but concerns around the toxicity of low levels of exposure are more recent.

People are exposed to lead when they inhale or ingest it. This usually happens when a product containing lead is burned or disturbed in some way. Children are more vulnerable to lead due to higher absorption levels per ingested dose, and their natural proclivity for putting things in their mouths.

Occupational lead exposure became a growing concern in the United States starting in the 1920s. Cases of lead poisoning popped up periodically, but took decades to gain enough political clout to overcome national lobbying efforts in favor of the usefulness of lead products.

MORE INFORMATION: Learn about symptoms of lead poisoning and its lasting effects

The Clean Air Act of 1970 gave the Environmental Protection Agency (EPA) the power to regulate pollutants in the United States. Lead was one of the pollutants the EPA focused on, putting in regulations and guidelines for removing lead from the manufacturing of gasoline, paint, toys, cosmetics and more.

In 1986, the EPA updated the Safe Drinking Water Act to limit the concentration of lead in public water systems. Before the end of 1987, lead was no longer being used in newly installed water pipes.

Still, the EPA and other regulators balked at the daunting – and expensive – task of requiring the removal or destruction of all products manufactured or installed before the regulations went into effect. This meant that things like lead paint or lead water service lines already in homes were only replaced if the individual homeowner had the money and desire to replace it.

Why are we now going back to replace them?

In short, the EPA revised its Lead and Copper Rule. That rule went into effect in 1991 and set stringent limits on the concentration of lead and copper allowed in public water systems. It was then revised in 2021 and 2024, adding mandates that all service line materials be identified and any containing lead be replaced – regardless of current lead levels in the water.

To add more context, this all stems from the water disaster in Flint, Michigan.

In April 2014, Flint’s drinking water source was changed from Lake Huron to the Flint River. This change was made in an attempt to save money. The area was dealing with decades of financial decline and taking water from the Flint River would greatly reduce the cost of transporting water all the way from Lake Huron.

For 1 year and 6 months, Flint River water flowed through the water utility system in Flint, Michigan. During that time nearly 100,000 people were exposed to elevated levels of lead in their drinking water.

But even when the water source was switched back to Lake Huron, problems remained.

That’s because neither the Flint River or Lake Huron were the source of the lead getting into people’s tap water. The source was the water service lines connected to many of the homes in the region. Many of those service lines had been installed before the EPA discontinued the use of lead water pipes.

The Flint River was much more naturally corrosive than Lake Huron. When water from the river, without proper corrosion control additives, began flowing through those lead pipes, the corrosive water caused the plumbing materials to corrode. The corroding pipes, connectors, valves, etc. exposed lead ions and resulted in them being released into the water.

When Flint officials learned that the water service lines were the source of the problem, they also learned that they had almost no verified data about the city’s service lines, due to outdated records.

The city then set out to identify and replace all the lead service lines.

The scope of the problem in Flint resulted in a push to eliminate these lead service lines throughout the entire United States. That’s why the EPA revised its Lead and Copper Rule in 2021 and 2024 to mandate that all public water utilities identify their service line materials and replace any that contain lead.