Water filters for lead have to be chosen on certification rather than on marketing, because lead is invisible, tasteless and enters the water from the pipes and fittings between the main and your tap rather than from the source. That also means the same house can have lead at one faucet and none at another, which changes where you put the filter.
Where lead comes from
Lead is not usually present in the water a utility sends out. It is picked up on the way to your glass from lead service lines, lead solder in copper joints, and brass fixtures containing lead. Corrosive water dissolves it, and water that has sat still in the pipes overnight picks up more than water that has just been running. That is why the exposure is highly variable between houses on the same street, and why running the tap before drinking after a long stagnation is a genuine, if partial, precaution rather than folklore.
The technologies that reduce it
Reverse osmosis rejects lead along with most dissolved metals and is the most thorough point-of-use answer. Specially formulated activated carbon blocks, often with an ion exchange component built in, are certified for lead reduction and cover pitchers, faucet mounts and under-sink cartridges. Distillation removes it by leaving it behind in the boiling vessel. What does not work is an ordinary sediment cartridge, since dissolved lead is not a particle, or a plain carbon block that carries no lead certification, since not all carbon is formulated for the job.
Certification is the thing to check
Lead reduction is a specific, independently tested performance claim. Look for a filter certified to the relevant standard for lead reduction and read the performance data sheet, not the box, because a manufacturer may certify one cartridge in a range and not another. Check whether the certification covers particulate lead, dissolved lead or both. Note the rated capacity in gallons as well, since a lead-certified cartridge only performs to the end of its rated volume and then keeps passing water while quietly doing less than it did on day one.
Find out what you have first
Every community water system publishes an annual Consumer Confidence Report and the EPA maintains a finder for it, which will tell you what the utility measured and whether lead service lines are known in your area. Because lead is picked up in your own plumbing, a utility report is a starting point rather than an answer, and a tap sample from your own kitchen is what actually settles it. Point of use is the right place for the filter: treating the kitchen tap you drink from is more effective than a main-line filter that leaves the last stretch of household plumbing untreated. Our replacement filter guide covers keeping certified cartridges current.
Questions people ask about water filters for lead
Do all water filter pitchers remove lead?
No. Only pitchers using a cartridge specifically certified for lead reduction do. A standard taste-and-odor carbon cartridge is not formulated for lead and should not be relied on.
Does boiling water remove lead?
No, it concentrates it. Water evaporates and the lead stays behind, so boiled water can carry more lead per glass than the water you started with.
Should a lead filter go on the main line or at the tap?
At the tap. Lead is picked up in household plumbing downstream of the main, so a whole-house filter can leave the final stretch of pipe untreated.
How do I know if my house has lead pipes?
Scratch an unpainted section of the service pipe: lead is dull gray, soft and scratches to a shiny silver. Your utility can also tell you what material your service line is recorded as.