What is Picloram* and Why Does It Matter?

Picloram is an herbicide — a weed-killing chemical — used widely in agriculture and rangeland management. Farmers and land managers apply it to control broadleaf weeds and woody plants, particularly on pastures and rights-of-way. Because picloram binds poorly to soil, it moves easily with rainwater and runoff into nearby streams, rivers, and groundwater. That mobility makes it one of the more persistent agricultural herbicides in drinking water systems across the country.

Health researchers have raised concerns about picloram's long-term effects, even at low doses. Animal studies show that chronic exposure can affect the liver and thyroid, and the EPA classifies picloram as a possible human carcinogen (cancer-causing agent). The keyword there is "possible" — the evidence comes primarily from animal research, and human data is still limited. That said, the liver and thyroid play critical roles in hormone regulation and overall metabolism, so even low-level disruption deserves attention. Children and pregnant women are generally considered more vulnerable to chemical exposures of this type.

The EPA's legal limit for picloram in drinking water sits at 500 parts per billion (ppb). That number sounds reassuringly high — and the good news is that none of the 95 water systems where picloram was detected came anywhere close to it. The average detected level across those systems was just 0.024 ppb, with a maximum of 0.323 ppb. However, the EPA's legal limits were set decades ago and don't always reflect the latest science on long-term, low-dose exposure. The Environmental Working Group (EWG) has not yet published a separate health guideline for picloram, but their broader framework encourages caution around any pesticide detected in drinking water, even below legal thresholds. Technically legal doesn't always mean risk-free.

Geographically, picloram detections follow a clear agricultural pattern. Texas accounts for 73 of the 95 affected water systems — by far the highest concentration in the country. That's not surprising. Texas has millions of acres of rangeland where picloram-based herbicides are commonly used to manage invasive brush species like juniper and mesquite. Iowa comes in second with 6 affected systems, reflecting its intensive row-crop agriculture. West Virginia and Louisiana each show 5 affected systems, and New York rounds out the top five with 2. In each of these states, the connection between agricultural land use and water contamination is direct. Runoff from treated fields and pastures carries picloram into local water sources, particularly after heavy rain.

The practical question is: what can you do about it? Activated carbon filtration — the kind found in many pitcher filters and under-sink systems — can reduce picloram levels, but its effectiveness varies depending on the filter quality and contact time with the water. For the most reliable protection, a reverse osmosis (RO) system is your best option. Reverse osmosis pushes water through a semi-permeable membrane that blocks contaminants at the molecular level, removing up to 99% of pesticides and herbicides including picloram. Echo Water's reverse osmosis systems are designed specifically for this kind of whole-home or point-of-use protection, giving you clean water at the tap without relying solely on your municipal treatment plant. If you live in Texas or another state with confirmed picloram detections, it's worth requesting your local water quality report — called a Consumer Confidence Report — to see exactly what your utility has found. Knowledge is always the first step, and filtration is the practical follow-through.

Regulatory Standards for Picloram*

Cities With the Highest Picloram* Levels

States Most Affected by Picloram*

Frequently Asked Questions

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