Lead in Drinking Water: Risks and Removal

What Is Lead?

Lead is a dense, soft heavy metal with the atomic number 82 and the chemical symbol Pb — derived from plumbum, the Latin word for lead. That etymology is not incidental: the Romans used lead extensively in their water infrastructure, and the English word plumbing traces directly to it. The connection between lead and water pipes is ancient, but the consequences of that connection are still playing out in American cities today.

What makes lead uniquely dangerous as a drinking water contaminant is that there is no known safe level of exposure. The EPA set its Maximum Contaminant Level Goal (MCLG) for lead at zero — the only value that reflects the scientific consensus that any detectable amount poses health risk. Lead is a cumulative neurotoxin. It does not flush from the body quickly; it accumulates in bones, blood, and soft tissue, where it can persist for decades.

The United States has known about lead’s dangers in plumbing for longer than most people realize. The 1986 amendments to the Safe Drinking Water Act banned the use of lead solder and lead pipes in new plumbing, and the 1988 Lead Contamination Control Act addressed lead in school drinking water. Yet because these laws applied prospectively — to new construction — they did nothing to remove the millions of lead service lines and soldered connections already embedded in the ground and inside homes across the country. That legacy infrastructure is why lead in drinking water remains a live public health concern four decades later.

How Lead Gets Into Drinking Water

Lead almost never enters source water naturally. Rivers, reservoirs, and groundwater aquifers contain very little of it. The contamination happens between the treatment plant and the tap — inside the distribution system and inside homes themselves.

The primary pathway is lead service lines (LSLs): the pipes that run from the water main in the street to the water meter at a home’s foundation. Nationwide, an estimated 9.2 million LSLs remain in service, according to EPA data. These pipes were standard practice in cities built before 1986, and they corrode over time, releasing lead directly into the water flowing through them.

Lead solder is the second major source. Before 1986, it was common practice to join copper pipes using solder containing up to 50% lead. Even a house with copper supply lines can have significant lead exposure if those lines are joined with pre-1986 solder. Fittings, valves, and brass fixtures — including faucets — are a third source; even fixtures certified as “lead-free” under current federal standards can legally contain up to 0.25% lead, and older fixtures contained far more.

The chemistry that drives lead release is corrosion. Low pH water (acidic) and low alkalinity are the primary culprits: acidic water dissolves lead from pipe surfaces more aggressively. Water temperature, chlorine levels, and the presence of certain minerals all affect the corrosion rate. Utilities are required to use corrosion control treatment — typically by adjusting pH or adding orthophosphate, which coats pipe interiors and reduces lead dissolution — but the effectiveness of these treatments varies.

The Flint, Michigan crisis illustrated what happens when corrosion control fails. From 2014 to 2019, the city switched its water source to the Flint River without implementing proper corrosion inhibitors. The more corrosive river water stripped the protective scale from pipes, releasing lead throughout the distribution system. Blood lead levels in children spiked. The crisis triggered federal investigations, criminal charges, and a national re-examination of how the EPA’s Lead and Copper Rule was being administered. Flint was an acute failure, but it reflected structural vulnerabilities present in water systems across the country.

Lead and copper often travel together in older plumbing systems — see our copper contaminant profile for details on that related risk.

Health Effects

Lead’s toxicity is dose-dependent, but the evidence base now supports treating zero as the safety threshold. The health effects differ meaningfully by population.

Children

Children are the highest-risk group by a wide margin. Their developing nervous systems absorb lead more readily than adults — a child’s gastrointestinal tract absorbs roughly 50% of ingested lead, compared to around 10% in adults. Lead crosses the blood-brain barrier and disrupts neurodevelopment at the cellular level.

Research consistently links early lead exposure to IQ reductions of approximately 2 to 5 IQ points per 5 µg/L (ppb) of blood lead concentration, with the steepest losses occurring at low-to-moderate exposures rather than only at high levels. The effect is not a cliff — it is a slope, and there is no identifiable threshold below which it disappears. Children exposed to lead show higher rates of attention deficit disorders, learning disabilities, impulsive behavior, and reduced executive function. These effects are largely irreversible. Lead absorbed during early childhood does not fully clear even if exposure stops.

For infant formula prepared with tap water, the risk is especially acute because infants consume a high volume of water relative to their body weight and have immature blood-brain barriers. Pediatricians and the CDC both advise that no blood lead level in children should be considered safe.

Adults

Adults are less neurologically vulnerable than children but are not unaffected. Chronic low-level lead exposure in adults is associated with kidney damage (nephrotoxicity), elevated blood pressure and hypertension, and cardiovascular disease. A 2018 Lancet study estimated that lead exposure contributes to roughly 412,000 deaths per year in the United States — with cardiovascular causes accounting for the majority. Reproductive effects in both men and women have also been documented, including reduced fertility and hormonal disruption.

Pregnant Women

Pregnancy creates a specific and underappreciated risk pathway. During pregnancy, maternal bone tissue is broken down to supply calcium to the developing fetus — and because lead is stored in bone alongside calcium, this process releases stored lead back into the bloodstream. A pregnant woman who was exposed to lead years or decades earlier can have elevated blood lead levels during pregnancy even with no current environmental exposure.

Placental transfer is efficient: lead crosses the placenta readily, exposing the fetus at precisely the period of greatest neurological vulnerability. Higher maternal blood lead is associated with preterm birth, low birth weight, and developmental delays in offspring. Pregnant women are advised to test their tap water and use appropriate filtration if lead is detected.

EPA Regulation and Limits

The EPA’s regulatory framework for lead in drinking water is called the Lead and Copper Rule (LCR), originally issued in 1991. After decades of criticism that the rule’s sampling protocols could be manipulated and its requirements were too weak, the EPA finalized a significant revision in October 2024: the Lead and Copper Rule Improvements (LCRI).

Standard	Old LCR (1991)	New LCRI (Oct 2024)
Action Level	15 ppb	10 ppb
Trigger Level	None	10 ppb
LSL Replacement	Best efforts	Mandatory 10-year timeline
Sampling Protocol	1st-liter draw	Dual (1st-liter + 5th-liter)
MCLG	0 ppb	0 ppb (unchanged)

The reduction in the action level from 15 to 10 ppb is significant but still draws criticism from public health advocates who note that the MCLG remains zero — meaning any detectable lead is above the health-protective goal. The mandatory 10-year LSL replacement timeline is the LCRI’s most consequential provision: for the first time, utilities are legally required to replace all lead service lines, not merely make “best efforts.” The dual-sample protocol addresses a known weakness in the old rule, under which utilities sometimes used pre-flushing or other techniques that artificially lowered reported lead concentrations. For a deeper look at the regulatory history and what LCRI means in practice, see our complete guide to lead in water.

How Widespread Is Lead?

The 9.2 million lead service lines still in service are not evenly distributed. They are concentrated in the Midwest and Northeast, in cities with older housing stock built before the 1986 ban. Chicago is the single largest challenge: the city has an estimated 400,000 LSLs, more than any other American city, and virtually every home connected to the water main through a service line installed before the mid-1980s has one.

Other cities with large LSL inventories include Milwaukee, Cleveland, Detroit, and Newark. Many smaller Midwestern cities have proportionally high rates even if their absolute numbers are lower. In these communities, the age of housing is a strong proxy for lead risk — a home built before 1940 is especially likely to have both LSLs and lead solder throughout interior plumbing.

The LCRI includes mandatory service line inventory requirements. Utilities must now compile and publish complete maps of their distribution systems identifying where LSLs exist, what materials are unknown, and the timeline for replacement. This transparency requirement represents a genuine improvement: for the first time, many communities will have public, searchable records of where lead pipes are located.

How WaterVerge Tracks Lead

WaterVerge pulls lead sampling data from the EPA Envirofacts Lead and Copper Rule (LCR) API, which aggregates results from utility compliance monitoring across all community water systems. For each city, we display the 90th percentile lead level — the metric the EPA uses to determine whether a system exceeds its action level, calculated from samples collected at high-risk locations in the distribution system.

We also track LCR violations: instances where a utility’s 90th percentile exceeded the action level, or where required monitoring or reporting was not completed. Violation history is meaningful context — a single exceedance does not necessarily mean ongoing risk, but a pattern of violations indicates systemic problems.

Because lead is so localized — a home with a lead service line may have very different results than a neighbor without one — city-level data has limits. We present it as a starting point and recommend supplementing it with your own tap testing, particularly if your home was built before 1986.

How to Remove Lead

If your water contains lead or you have reason to believe your plumbing puts you at risk, filtration is the most reliable protection available to households. Not all filters remove lead — activated carbon alone does not — so the filter type and certification matter.

Method	Removal Rate	Certification	Best For
Reverse osmosis (under-sink)	95—99%	NSF/ANSI 58	Comprehensive removal, high volume
Pitcher filter (NSF 53 certified)	Up to 99%	NSF/ANSI 53	Affordable, no installation
Faucet-mount filter	95—99%	NSF/ANSI 53	Convenience, point-of-use
Whole-house filter	Varies	NSF/ANSI 53	Full home coverage (rare, expensive)

Reverse osmosis systems are the gold standard for lead removal. Installed under the sink, they use a semipermeable membrane to block lead ions before water reaches the tap. They also remove a wide range of other contaminants. The trade-off is cost (typically $150—400 installed) and the production of reject water.

NSF/ANSI 53 certified pitchers are the most accessible option and, when certified, effective. The NSF 53 standard specifically requires lead reduction testing, so certification is not optional — it is the only meaningful guarantee. Our guide to the best water filter pitchers covers the top certified options with current pricing.

Faucet-mount filters certified to NSF 53 offer similar removal rates at a lower cost than under-sink systems and are worth considering for renters or those who cannot modify plumbing.

Whole-house systems capable of lead removal exist but are expensive and less common. For most households, point-of-use filtration at the kitchen tap and a dedicated drinking water filter is the more practical approach.

Operational tips that matter:

• Always use cold water for drinking, cooking, and especially infant formula. Hot water dissolves lead from pipes much more aggressively than cold.
• Flush your tap for 30 seconds to 2 minutes before drawing water for consumption, especially after the tap has been unused for several hours. This clears standing water that has been in contact with lead-containing plumbing.
• Never use hot tap water to prepare baby formula or food for young children under any circumstances, regardless of filtration.

What does not work: Standard activated carbon filters not certified to NSF 53 for lead — including many popular pitcher brands and most refrigerator filters — do not reliably remove lead. Boiling water does not remove lead; it concentrates it as water evaporates. Water softeners are not designed for lead removal and should not be relied upon for this purpose.

Check Your City

Lead risk varies dramatically by location, water system, and the age of your home’s plumbing. WaterVerge tracks 90th percentile lead data, violation history, and LSL inventory status for thousands of US water systems.

Search your city to see the latest lead data for your local water utility, including any action level exceedances, open violations, and infrastructure details from the EPA’s monitoring records.