Lead
A neurotoxic metal that leaches from old pipes and solder. No safe level for children.
The science, plainly.
Lead is a heavy metal that was used in service lines, plumbing solder, and brass fixtures for most of the 20th century. It does not occur in source water at meaningful levels — it gets into tap water on the trip from the main into your house, especially when water sits in the pipes for hours.
The pathways into the tap.
- Lead service lines (still ~9 million in the U.S.)
- Lead solder in pre-1986 plumbing
- Brass faucets and fittings (legal up to 0.25% lead through 2014)
- Galvanized pipes downstream of lead
What the evidence shows.
There is no known safe blood lead level in children. Lead exposure during fetal development and early childhood is associated with permanent reductions in IQ, learning, and attention. In adults, chronic exposure is linked to high blood pressure, kidney impairment, and cognitive decline.
Children & infants
Even low-dose lead exposure is linked to lower IQ, behavioral problems, and slowed growth. Formula prepared with tap water is a major exposure route in lead-pipe homes.
Pregnancy
Lead crosses the placenta. Maternal exposure is associated with preterm birth and reduced fetal growth.
Adults
Long-term exposure is linked to elevated blood pressure, cardiovascular disease, kidney damage, and reproductive harm.
What the law allows vs. what's actually safe.
EWG and the American Academy of Pediatrics recommend treating any detectable lead as a problem.
Note: Lead is regulated by an 'action level' at the tap, not a strict MCL. If more than 10% of homes tested exceed the action level, utilities must take corrective action.
Where exposure is highest.
Highest risk in older urban housing stock — concentrated in the Midwest and Northeast (e.g., Chicago, Cleveland, Milwaukee, Detroit, New York City).
Filtration that actually works.
- NSF/ANSI 53 certified carbon block filters
- Reverse osmosis (NSF/ANSI 58)
- Distillation
We don't recommend brands. The certification on the box matters more than the brand printed on it. Look for the actual NSF/ANSI standard number specific to the contaminant you're removing.
Sources
- Lead and Copper Rule Improvements (Final Rule, October 2024) — U.S. Environmental Protection Agency
- Sources of Lead Exposure — Centers for Disease Control and Prevention
- Lead Pipes Are Widespread and Used in Every State — Natural Resources Defense Council
- Lead Service Line Inventory — U.S. Environmental Protection Agency