What is Glyphosate and Why Does It Matter?

Glyphosate is the active ingredient in Roundup, one of the most widely used weed killers in the world. Farmers spray it on corn, soybeans, wheat, and dozens of other crops to control weeds before and after harvest. Rain carries it off fields and into streams, rivers, and groundwater — which often feed the same municipal systems that supply your tap water. It has now been detected in 33 water systems across the United States, with an average concentration of 1.907 parts per billion (ppb) and a peak level of 6.0 ppb.

The health concerns around glyphosate have grown significantly over the past decade. In 2015, the World Health Organization's cancer research agency classified it as "probably carcinogenic to humans," meaning there is credible evidence linking it to cancer in animal studies and some human research. More recent studies have focused on non-Hodgkin's lymphoma, a type of blood cancer, as a potential risk at higher exposure levels. Beyond cancer, some research suggests glyphosate may disrupt hormone function and harm gut bacteria, though scientists are still studying these effects. Children are considered more vulnerable than adults because their bodies are still developing and they consume more water relative to their body weight.

Here is where the regulatory picture gets complicated. The EPA sets the legal limit for glyphosate in drinking water at 700 ppb — a number so high that most detections look harmless by comparison. But the Environmental Working Group (EWG) sets its own health guideline at just 1 ppb, based on a more conservative reading of the cancer risk data. Of the 33 systems where glyphosate was detected, 4 tested above that 1 ppb EWG guideline. That gap between 1 ppb and 700 ppb is not a small rounding difference — it is a 700-fold difference in what different authorities consider acceptable. The EPA's limit was last updated decades ago and has not fully incorporated newer cancer research. For families trying to make informed decisions, the EWG guideline is the more protective benchmark to use.

Geographically, glyphosate detections follow the country's agricultural map closely. Iowa leads with 17 affected systems — no surprise given that the state sits at the heart of the Corn Belt, where glyphosate use per acre is among the highest in the nation. Florida accounts for 10 affected systems, reflecting heavy herbicide use in its sugar cane fields and citrus groves. South Carolina, Georgia, and New Hampshire each reported 1 affected system. The Iowa concentration is particularly worth watching. Heavy spring rains wash glyphosate from recently treated fields into waterways before treatment plants can fully address the spike. Rural water systems with limited filtration infrastructure are often the most exposed.

The good news is that effective filtration options exist. Activated carbon filters can reduce glyphosate levels, but the most reliable protection comes from reverse osmosis (RO) filtration. A quality reverse osmosis system forces water through a semi-permeable membrane with pores small enough to block glyphosate molecules, removing up to 99% of the herbicide from your drinking water. Echo Water's reverse osmosis systems are designed specifically for this kind of whole-contaminant protection, addressing glyphosate alongside other agricultural chemicals, heavy metals, and disinfection byproducts in a single system. If you are on a municipal system in Iowa or Florida — or anywhere with significant farming activity nearby — an RO filter at your kitchen tap is a straightforward and proven step. Check your annual water quality report (called a Consumer Confidence Report) to see whether your utility tests for glyphosate. Many do not, which makes home filtration an even smarter precaution.

Regulatory Standards for Glyphosate

Cities With the Highest Glyphosate Levels

States Most Affected by Glyphosate

Frequently Asked Questions

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