Is Glyphosate in Your Drinking Water? What the Data Actually Shows
Glyphosate is the most widely used herbicide in the United States, and it isn't hard to find in surface water. A U.S. Geological Survey study sampled 70 streams and rivers from 2015 through 2018 and detected glyphosate at least once at 66 of the 70 sites. The same release adds the sentence that rarely makes the headlines: "Measured concentrations of glyphosate did not exceed human-health or aquatic-life benchmarks."
Detection and exceedance aren't the same finding, and most of what you need to know sits in the gap between them. Streams aren't finished tap water, either. The Minnesota Department of Health reports that glyphosate has been detected only four times in Minnesota public drinking water systems since 1993, at 1.1 to 39 micrograms per liter. So the useful question isn't whether glyphosate is out there. It's whether it's in your water, at what level, and what would actually take it out.
Key Takeaways
Common in Streams, Rare at the Tap
Wells Are Unregulated, Not Worse
The Agencies Asked Different Questions
Treatment Claims Need Glyphosate Data
Why Glyphosate Is Back in the News in 2026
Two federal actions put it there. On February 18, 2026, the President signed Executive Order 14387, which treats domestic production of glyphosate-based herbicides as a national defense priority. The order says these herbicides "play a critical role in maintaining America's agricultural advantage," notes that there's only a single domestic producer, and gives the Secretary of Agriculture Defense Production Act authority for "ensuring a continued and adequate supply."
That's an order about securing supply. Drinking water limits are a separate matter, set by EPA under the Safe Drinking Water Act. What the order did do is send a lot of people looking for whether the herbicide is in their water.
The second action is quieter. EPA says it's updating its evaluation of glyphosate's carcinogenic potential and its human health risk assessment, with completion anticipated in late 2026, and in August 2026 it opened a public comment period on the literature review behind that work. The science summary below is current as of September 2026, and it may move.
How Glyphosate Reaches Water, and Where It Usually Doesn't
Glyphosate is a non-selective weed killer that works by stopping the shikimic acid pathway, an enzyme pathway plants need to make certain proteins. The National Pesticide Information Center notes that it was first registered for use in the U.S. in 1974, and that people apply it "in agriculture and forestry, on lawns and gardens, and for weeds in industrial areas."
Where it goes next depends on the soil. NPIC explains that glyphosate binds tightly to soil, can persist there for up to six months depending on the climate and soil type, and is broken down by soil bacteria. Because it binds so tightly, NPIC says it's not likely to get into groundwater. Minnesota's monitoring lines up with that: the state's groundwater sampling hasn't yet detected it, even though it's frequently found at low levels in both urban and rural surface water.
Surface water is the main route. USGS found the highest concentrations where agricultural or developed land was nearby, and occurrence rose with the amount of glyphosate used for agriculture in the watershed. That makes the source of your water the first thing to figure out.
- Public water systems: glyphosate is a regulated contaminant with an enforceable federal limit, listed in EPA's National Primary Drinking Water Regulations. Systems that draw on rivers and streams sit closest to the route USGS measured.
- Private wells: EPA is plain about this. The quality of water from private domestic wells isn't regulated by the federal government under the Safe Drinking Water Act, and well owners are responsible for their own water. Glyphosate is unlikely to reach groundwater, but nobody else is going to check.
What the Health Agencies Actually Concluded
This is where glyphosate gets confusing, because the two conclusions people quote sound like they contradict each other.
In March 2015, the World Health Organization's International Agency for Research on Cancer (IARC) classified glyphosate as "probably carcinogenic to humans" (Group 2A). IARC based that on "limited" evidence of cancer in humans and "sufficient" evidence in experimental animals. Several of the human studies it weighed showed increased cancer rates in occupational settings, and the cancer type those studies kept pointing to was non-Hodgkin lymphoma.
The U.S. Environmental Protection Agency reached a different conclusion. In its words, "In its 2017 assessment, EPA concluded that glyphosate is not likely to be carcinogenic to humans," and its 2017 human health assessment "found no dietary risks of concern, including from drinking water."
EPA explains the gap itself: the two evaluations "differed in scope and methodology." IARC asks whether a chemical is capable of causing cancer under any conditions. EPA assesses risk under expected real-world exposures. The Minnesota Department of Health adds a practical point that fits here, noting that people are most likely to come into contact with glyphosate when they mix or apply it. Someone handling herbicide on the job and a family drinking from a public water system aren't in the same exposure situation.
What About AMPA, the Breakdown Product?
When glyphosate breaks down in the environment, one of the products is AMPA (aminomethylphosphonic acid). It shows up often. In the USGS stream study, AMPA was detected in 80 percent of samples at 84 percent of the sites, more often than glyphosate itself. USGS also notes that human-health and aquatic-life benchmarks aren't available for AMPA, so there's no limit to compare those detections against. That's an honest gap in the science, not a hidden danger and not an all-clear.
The Legal Limit, and What It Covers
EPA's maximum contaminant level for glyphosate is 0.7 milligrams per liter (700 parts per billion), and its health goal for the contaminant is set at the same 0.7 mg/L. EPA lists kidney problems and reproductive difficulties as the potential health effects of exposure above that limit, and runoff from herbicide use as the common source. The limit is legally enforceable for public water systems.
Some states go further in their guidance. The Minnesota Department of Health developed a guidance value of 500 parts per billion (0.5 mg/L), and it describes its guidance values as built to protect the people most vulnerable to a contaminant's effects. Check your own state's health or environmental agency for anything similar where you live.
One thing the federal limit doesn't do is follow you home to a private well. If you're on a well, 0.7 mg/L is a useful yardstick for reading a test result, but no one's required to measure your water against it.
How to Find Out If Glyphosate Is in Your Water
The only way to know whether glyphosate is in your water, and at what level, is a lab analysis. Here's a sensible order to work in.
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Start with your source.
If you're on city water, read your utility's annual water quality report, often called a Consumer Confidence Report, and look for glyphosate. If it isn't listed, ask the utility whether and when it sampled for it rather than assuming either way. If you're on a private well, the decision to test is yours.
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Decide whether testing is worth it.
A glyphosate test makes the most sense for a well close to land where herbicides are applied, for a household using surface water that isn't treated by a public system, or for anyone who simply wants a number instead of a guess. Given how rarely glyphosate reaches groundwater, a well far from any application should get the standard checks first.
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Use a glyphosate-specific test.
Crystal Quest's Informational Glyphosate Water Test ($175) is analyzed by our partner lab, National Testing Laboratories, and screens only for glyphosate, with a detection limit of 0.1 mg/L. Our well water test (from $159) covers a much broader panel, but glyphosate isn't on its analyte list, so it's a separate order.
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Read the result against the right yardstick.
A detection limit of 0.1 mg/L is one seventh of EPA's 0.7 mg/L limit. A "not detected" result tells you your water is well below the federal standard. It doesn't tell you the concentration is zero, and trace levels like the ones Minnesota recorded would sit below that detection limit.
For the rest of the process, our guides to testing your water at home and testing well water cover the broader testing picture, and our guide to water contaminants covers what else is worth checking.
What Actually Removes Glyphosate From Water
This is where a lot of online advice goes wrong. You'll find confident removal percentages for carbon filters and reverse osmosis, and we haven't been able to trace them to a primary source. Here's what the regulation and the research actually say.
At Public Water Systems: Oxidation
Federal drinking water rules list the best available technologies for meeting each organic contaminant limit. In that table, part of 40 CFR 141.61, the options are granular activated carbon, packed tower aeration and oxidation. For herbicides such as alachlor and diquat, the table marks granular activated carbon. For glyphosate, it marks oxidation alone.
That tells you glyphosate doesn't behave like a typical pesticide molecule. Researchers keep describing the same challenge: it's small, highly polar and carries a negative charge across most of the everyday pH range, which makes it harder to catch than many other organic contaminants.
Membrane Filtration: Promising, With Conditions
Membranes can reject glyphosate, but the details matter. A 2026 laboratory study in Nature Communications found that nanofiltration membranes with a molecular weight cut-off above 150 daltons, a measure of how small a molecule the membrane holds back, removed about 90 percent of glyphosate when it carried a negative charge, across a pH range of 4 to 12, and that removal dropped sharply at higher applied pressures, in one case from 86 to 28 percent.
A 2010 study in Water Science and Technology assessing a drinking water treatment plant equipped with reverse osmosis followed by activated carbon found that removal of most organic micropollutants was high for all the membranes tested, but it named glyphosate among the ones removed less efficiently. Put together, reverse osmosis is a reasonable barrier for drinking water, not a guaranteed one, and no single percentage honestly describes every membrane in every home.
Activated Carbon: It Depends Heavily on the Carbon
Carbon results for glyphosate vary widely. In a 2023 lab study in Environmental Monitoring and Assessment, activated carbon cloth adsorbed 42.5 percent of glyphosate from solution without an applied electrical current. Engineered carbons can do far better: in a 2023 study in the Journal of Hazardous Materials, a polymer-based spherical activated carbon removed 95 percent of glyphosate from a starting concentration of 1 microgram per liter, with surface area playing a key role. "Contains carbon" on a label doesn't tell you which end of that range you're getting.
Choosing a Home System Without Guessing
If a test shows glyphosate at a level you want to reduce, the most practical target is the water you drink and cook with. Before you buy anything, ask a few direct questions:
- Does the performance data name glyphosate specifically, not just "herbicides" or "pesticides"?
- What starting concentration and water conditions was it tested at?
- Was the testing done by an independent lab, on the same model you're buying?
- How often do the carbon stages and the membrane need replacing to hold that performance?
Crystal Quest's Thunder 1000C under-sink system ($298.40) combines both barriers discussed above: 12 stages, including a granulated activated carbon stage listed for herbicides and pesticides, ahead of a reverse osmosis membrane. We'll be straight with you, though. We don't publish a glyphosate-specific removal figure for it, which is the same standard we're asking you to hold every seller to. That's why the next step matters.
The Step Most People Skip: Test the Treated Water
If your first result was above the test's 0.1 mg/L detection limit, send a second glyphosate test once your system is installed, this time drawn from the treated tap. It's the only result that shows how your system performs on your water, and it turns a manufacturer's claim into something you've checked yourself. For more on how membrane systems work, see our guide to reverse osmosis water filtration.
Get a number, not a guess.
A lab-analyzed glyphosate test shows where your water stands against EPA's limit, and a second test after treatment shows whether your system is doing its job.
Frequently Asked Questions About Glyphosate in Drinking Water
Does a pitcher filter remove glyphosate?
Only trust one whose performance data names glyphosate. Lab results for carbon range from modest to strong depending on the carbon, so a carbon cartridge alone isn't evidence either way. If it matters to you, test the filtered water.
Does a "not detected" result mean my water has no glyphosate?
It means the concentration is below the lab's detection limit. For Crystal Quest's glyphosate test that's 0.1 mg/L, one seventh of EPA's 0.7 mg/L limit, so a nondetect tells you you're well under the federal standard rather than at zero.
