Lead in water is a toxic metal contamination that happens when lead from old plumbing dissolves into your drinking water. It’s colorless, odorless, and tasteless, which means you can’t detect it without testing. The EPA’s official safety goal for lead in drinking water is zero, because no amount of lead exposure is considered safe.
How Lead Gets Into Drinking Water
Lead doesn’t typically come from your local water source or treatment plant. It enters the water on the way to your tap, through a chemical reaction between your water and the plumbing it flows through. When water sits in contact with lead-containing materials, it gradually dissolves small amounts of metal into the water. This process is called corrosion.
The most common sources of lead in household plumbing include lead service lines (the pipe connecting your home to the water main), lead solder used to join copper pipes, and brass faucets or valves that contain small percentages of lead. Homes built before 1986 are most likely to have lead solder, and homes built before the 1950s may have lead service lines entirely.
Several factors determine how much lead actually leaches into your water. Acidic water or water with low mineral content corrodes pipes faster. Hot water dissolves more lead than cold. Water that sits in pipes for hours, like overnight or during a workday, absorbs more lead than water that flows regularly. Even the age and condition of the pipes matters: newer lead pipes without a protective mineral coating on the inside tend to leach more.
Health Effects in Children
Children are especially vulnerable to lead because their developing bodies absorb it more readily than adults. Even low levels of lead in a child’s blood have been shown to cause measurable harm. The effects target the brain and nervous system, leading to lower IQ, decreased ability to pay attention, and underperformance in school. Lead exposure in children is also linked to slowed growth and development, hearing and speech problems, and behavioral difficulties.
What makes lead particularly dangerous for children is that these effects can be permanent. There is no way to reverse neurological damage once it occurs. And because lead builds up in the body over time, even small daily exposures from drinking water can accumulate to harmful levels, especially in infants who drink formula mixed with tap water.
Health Effects in Adults and Pregnant Women
Adults with long-term lead exposure face increased risk of high blood pressure, kidney damage, and reproductive problems. The effects are slower to appear than in children but no less serious over years of exposure. Lead is stored in bones and can be released back into the bloodstream during periods of stress, illness, or aging.
Pregnant women face a unique risk: lead passes from parent to unborn baby. Lead exposure during pregnancy can cause the baby to be born too early or too small. Because pregnancy can mobilize lead stored in bones from past exposures, even women who haven’t been recently exposed may carry a risk if they had significant lead exposure earlier in life.
What the Regulations Say
The EPA’s maximum contaminant level goal for lead in drinking water is zero. That’s not an enforceable standard, though. It’s a health-based target acknowledging that no level of lead is safe. The enforceable rule, called the Lead and Copper Rule, requires water systems to monitor lead levels at customer taps. If lead concentrations exceed an action level of 15 parts per billion (ppb), the water system must take steps to control corrosion and notify the public.
That 15 ppb threshold doesn’t mean water below it is safe. It’s a regulatory trigger, not a health standard. Any detectable amount of lead in water adds to your overall exposure from other sources like soil, old paint, and certain consumer products.
How to Check Your Plumbing for Lead
You can do a simple test at home to check whether your service line is made of lead. Find the pipe where your water supply enters your basement or crawl space. Lead pipes are gray or dull silver in color. Scratch the surface gently with a house key: if the scratched area turns shiny silver, the pipe is likely lead. You can also hold a strong magnet to the pipe. Lead is not magnetic, so if the magnet doesn’t stick and the scratch test shows shiny silver, you’re looking at a lead pipe.
Copper pipes are a reddish-brown color and also non-magnetic, but they won’t turn shiny silver when scratched. Galvanized steel is gray but magnetic. These simple tests help you identify the material, but the only way to know your actual lead levels is to have your water tested. Many local water utilities offer free or low-cost testing kits.
Reducing Lead Exposure at Home
If you know or suspect lead in your plumbing, the most effective long-term solution is replacing lead service lines and lead solder. That’s expensive and time-consuming, so several interim steps can significantly reduce your exposure.
Flushing your tap before drinking is one of the simplest measures. Run cold water for 30 seconds to two minutes before using it for drinking or cooking, especially first thing in the morning or after the water has been sitting for several hours. This clears out the water that has been in contact with lead pipes the longest. Always use cold water for cooking and preparing baby formula, since hot water pulls more lead from pipes.
Water filters are highly effective when you choose the right one. Look for filters certified to NSF/ANSI Standard 53, which is the specific certification for lead reduction. Pitcher filters, faucet-mounted filters, and under-sink systems are all available with this certification. If you prefer a reverse osmosis system, look for certification to NSF/ANSI Standard 58. Not all water filters remove lead, so checking for these specific certifications matters.
If you have young children or are pregnant, getting your water tested and using a certified filter provides the most practical protection while you determine whether pipe replacement is feasible. Many cities are currently undertaking lead service line replacement programs, so it’s worth checking whether your water utility has a timeline for your neighborhood.