Does a Water Filter Remove Lead? What the Test Data Shows

Some water filters reduce lead, and the ones worth trusting have independent test results to show it. “Lead-free” and “reduces lead” are two different things, and ideally a water filter does both. Here’s how to tell the difference, and how to read the test results behind a lead claim.

See the Test Results

Evidence, more than the brand name, is what sets filters apart.

Which water filters actually remove lead?

Plenty of filters say they help with lead, and fewer can show it. The way to tell them apart is the evidence behind the claim: an independent lab test that shows what went in, what came out, and for how many gallons.

Here’s what a solid lead test looks like. The lab adds lead to water at 150 micrograms per liter (µg/L, which is the same as parts per billion, or ppb), far more than most taps carry, and runs it through the filter. To pass, the filter has to bring that down to 5 µg/L or less, sample after sample, across the gallons being tested. That method comes from NSF/ANSI 53, the standard for filters that reduce health-related contaminants, and reverse osmosis systems use a sister standard, NSF/ANSI 58.

When you read a report or a listing, check three things: that lead is named, how many gallons it was tested to, and who ran the test. A general “NSF” badge on its own doesn’t tell you anything about lead.

The BOROUX rows come from the IAPMO R&T Lab reports described below, and both runs used a 150 µg/L challenge and a 5 µg/L pass limit.

Is “lead-free” the same as removing lead?

They’re two different promises, and a good filter keeps both. “Lead-free” is about the filter itself: the parts that touch your water can’t contain more than a trace of lead. Under EPA’s definition, that means a weighted average of no more than 0.25% lead across those wetted surfaces, and 0.2% for solder and flux. That matters more than it sounds, because a filter that added lead to your water would undo the very job you bought it for.

The standard behind the badge is NSF/ANSI/CAN 372. It’s a materials standard, so it answers “does this product add lead?” Lead reduction is a separate question, answered by a performance test like the ones below. Our Foundation Filters are WQA certified to NSF/ANSI/CAN 372, so the hardware is covered, and the lab reports below show what happens to the lead in the water. That combination is the one worth looking for.

What a real lead test looks like

The most important thing to look for is independence, or third-party status. Testing should always be done by a neutral, professional organization, because in-house results are hard for anyone else to verify. The testing house used for the Foundation Filters was IAPMO R&T Lab in New Jersey, an accredited lab that meets ISO/IEC 17025 (the international quality standard for testing labs), using an R&D test to the NSF/ANSI 53 lead-reduction method. Two tests were performed because water acidity and alkalinity change how lead behaves:

• pH 6.5, 4,000 gallons: lead dropped from 150 µg/L to an average of 1.7 µg/L, with no sample above 3 µg/L. That’s a 98.87% average reduction.
• pH 8.5 with particulate lead, 450 gallons: lead dropped from 150 µg/L to an average of 1.6 µg/L, a 98.93% average reduction. Particulate lead is lead carried as tiny solid specks rather than dissolved in the water.

The two pH tests used different protocols, so the 4,000-gallon figure doesn’t carry over to alkaline water, which means each test is best read on its own terms. You may also see “up to 99.36%,” which is the best single sample in the pH 6.5 run rather than its average. The lab tested a single filter, and our methodology note says a two-filter system can double the gallons.

Review the reports: the pH 6.5 lab report, the pH 8.5 lab report, and the full test-report page.

Certifications are separate from test reports. The filter is WQA certified to NSF Standards: NSF/ANSI 42, NSF/ANSI/CAN 372, and NSF/ANSI/CAN 401, and you can look those up on the certifications page and the WQA listing.

Do carbon and gravity filters remove lead?

Activated carbon block filters can reduce lead when they’re designed and tested for it. “Gravity” just describes what powers the system: gravity itself doesn’t filter anything, so the work is all done by the filter element. Activated carbon has an enormous amount of surface area, and lead can stick to it in a process called adsorption, while a dense carbon block can also physically block small particles.

The capacity is finite, though. As Consumer Reports explains, the experts there liken activated carbon to a Velcro wall: eventually there’s no room left for new contaminants to stick, and other contaminants compete for the same spots. That’s why replacement timing is part of the lead claim. The same Consumer Reports experts note that heat can interfere with adsorption, which is one more reason to use cold water. Lead filters also aren’t tested above 150 ppb, so a filter’s result doesn’t cover water with more lead than that. In practice, a filter on your counter is only as good as its last change date.

That covers what a filter can do, but it also helps to know where the lead comes from in the first place.

How does lead get into tap water?

Usually it gets there after the water leaves the treatment plant. EPA’s overview says the most common sources are lead pipes, faucets, and fixtures, and lead service lines, the pipes that connect your home to the water main, are typically the most significant source. Homes built before 1986 are more likely to have lead pipes, solder, or fixtures, which is why an older house is where a test matters most.

Corrosion and standing water make things worse, because water that sits in pipes for hours can dissolve more lead. You can’t see, taste, or smell it, so the first real signal is usually a test or a notice from your water system, and that raises the question of how much a small amount should worry you.

Is any amount of lead in water safe?

Health agencies are careful on this point. EPA and CDC agree that there is no known safe level of lead in a child’s blood, and for drinking water, EPA has set the maximum contaminant level goal at zero. That is a public health goal, not an enforceable line under which everything is considered harmless. EPA also says drinking water can make up 20% or more of a person’s total lead exposure, and 40% to 60% for infants who consume mostly mixed formula.

EPA’s list of possible effects is why the goal is zero. In children, even low exposure is linked to behavior and learning problems, lower IQ, hyperactivity, slowed growth, hearing problems, and anemia. During pregnancy, exposure is linked to reduced fetal growth and premature birth. In adults, it is linked to cardiovascular effects, decreased kidney function, and reproductive problems. CDC adds that the effects of lead poisoning can be permanent and disabling.

Since you can’t judge lead by look or taste, testing is how you find out whether this is a question for your house at all, and it comes before any filter decision.

How to check your water and lower your exposure

Testing usually costs $20–$100 through a state-certified lab, and some local health departments offer kits. If you’d like a walkthrough, there’s a guide to testing your own tap water.

While you wait on results, these simple steps come straight from EPA and CDC:

• Use cold water for drinking, cooking, and baby formula.
• If the tap hasn’t run for several hours, flush it until the water is noticeably cold.
• Clean the faucet aerator; lead particles can collect there.
• Boiling does not remove lead.
• Don’t run hot water through a filter, and replace the filter on schedule.

Testing and filters deal with your own tap, but a bigger fix is also underway, because the rules for lead pipes are changing.

What’s changing for lead pipes

EPA finalized the Lead and Copper Rule Improvements in October 2024. The action level is the lead concentration that obliges a water system to act, which makes it a regulatory trigger rather than a health threshold, and EPA’s health goal remains zero. Under the new rule, the action level drops from 15 µg/L to 10 µg/L on November 1, 2027. Most systems with lead service lines must replace them within 10 years. EPA estimates up to 9 million homes and businesses are still connected through legacy lead pipes, and systems with repeated exceedances will have to make filters available.

As of late 2026, that schedule remains the current rule, so if you’re reading this later, check the EPA page for updates. The rule sets a timeline for water systems, but it doesn’t replace testing your own tap in the meantime.

What to do next

Start with a water test, then choose a filter by its lead-reduction test results as well as its lead-free certification. If a gravity carbon block filter fits your situation, the BOROUX Foundation filter has the published test data to back it up: 4,000 gallons at pH 6.5 and 450 gallons at pH 8.5.