Lead in Drinking Water: Risks and What to Do
Lead almost never starts at the treatment plant. It comes from the service line and plumbing between the main and your tap. That makes it one contaminant you can do something about directly.
Lead is the contaminant that breaks the usual rules. Most substances we worry about are in the source water and removed by treatment. Lead is the reverse: the water leaving the plant is typically lead-free, and the metal is picked up on the way to your glass, from a lead service line or from solder, brass fixtures, and older pipes inside the home. That is why two houses on the same street can have very different lead levels.
Why lead is different
Because the problem is in the pipes, your utility’s report can tell you the system is compliant while your own tap still delivers lead. Lead also enters intermittently, leaching faster from water that has sat in the pipes overnight or that is more corrosive. This makes it invisible without testing and means the fixes are about your plumbing and your habits, not the treatment plant.
Where it comes from
The largest single source is the lead service line, the pipe connecting the water main to the home, common in houses built before the mid-1980s. Inside the home, lead can come from lead solder used on copper pipe before it was banned, from older brass faucets and valves, and from galvanized pipe that absorbed lead over decades. Hot water dissolves lead more readily, which is why you should never cook or make baby formula with hot tap water.
The health risks
There is no known safe level of lead exposure. In children, lead affects the developing brain and nervous system and is linked to lower IQ, attention problems, and slowed growth, with effects that can be permanent. In adults, it is associated with higher blood pressure, kidney problems, and reproductive harm. Pregnant women and young children are the most vulnerable, which is why lead gets more attention than its frequency alone would suggest.
The rules and the action level
The EPA regulates lead through the Lead and Copper Rule. Rather than a simple maximum contaminant level, it uses an "action level": if more than 10 percent of sampled taps exceed it, the utility must take corrective steps. The Lead and Copper Rule Improvements, finalized in 2024, lowered that action level from 15 parts per billion to 10 parts per billion and require water systems to identify and fully replace lead service lines, with most systems beginning the new compliance regime in late 2027.
| Item | Detail |
|---|---|
| Health-based goal (MCLG) | Zero. There is no safe level. |
| EPA action level | 10 ppb (lowered from 15 ppb under the 2024 LCRI) |
| Main source | Lead service lines and home plumbing, not the source water |
| Most at risk | Infants, young children, and pregnant women |
How to protect your home
Start by finding out whether you have a lead service line; many utilities now publish inventories, and your water provider can tell you. Then take practical steps: run the tap until it is cold before drinking or cooking if the water has been sitting, use only cold water for drinking and formula, and clean faucet aerators where particles collect. The reliable confirmation is a water test, since lead is invisible and tasteless. If lead is present, use a filter certified to NSF/ANSI Standard 53 for lead reduction, covered in our guide to home water filters, and pursue replacement of any lead service line. Replacing the pipe is the permanent fix; filtering and flushing manage the risk in the meantime.