Antimony in Drinking Water: Complete Guide (2026)

What is Antimony and Why Does It Matter?

ANTIMONY IN DRINKING WATER: WHAT YOU NEED TO KNOW

What Is Antimony and How Does It Get Into Your Water?

Antimony is a naturally occurring metal found in soil and rock throughout the United States. It enters drinking water supplies in two main ways. First, it leaches into groundwater from mineral deposits, especially in areas with certain geological formations. Second, it comes from industrial activities like mining, metal smelting, and manufacturing of batteries and semiconductors. Once in the water system, antimony doesn't break down or disappear — it stays in the water until it's removed through treatment.

The metal is particularly stubborn because it exists in two different chemical forms in water. Some antimony compounds dissolve easily in water, while others settle as particles. This makes antimony trickier to remove than some other contaminants, since different removal methods work better on different forms.

Health Effects: What the Research Shows

The EPA set the drinking water standard for antimony at 6 parts per billion (ppb) based on animal studies showing it can affect the liver, kidney, and heart with long-term exposure. However, the Environmental Working Group (EWG), which bases its guidelines on more recent research, recommends a stricter limit of 1.3 ppb for lifetime exposure.

At higher levels, antimony exposure has been linked to several health concerns. Animal studies show that chronic exposure can damage the liver and kidneys, increase blood sugar levels, and affect heart function. Pregnant women and young children are considered more vulnerable to these effects because their bodies are still developing. The EPA classifies antimony as a possible human carcinogen based on limited evidence, though more research is ongoing.

Most people exposed to antimony at typical drinking water levels won't notice immediate symptoms. The danger lies in long-term exposure — the kind that happens over months and years of drinking contaminated tap water. This is why even low levels matter, especially for families who rely entirely on tap water.

Regulatory Standards and Where the Gap Lies

The EPA's drinking water standard of 6 ppb has remained unchanged since 1992. The EWG's health guideline of 1.3 ppb reflects newer toxicology research that wasn't available three decades ago. Currently, 128 water systems across the United States serve water with antimony levels above the EWG guideline, though most stay below the EPA legal limit.

This gap between the EPA standard and EWG guideline matters for your family's protection. Just because water is "legal" doesn't mean it's as safe as it could be. If your water tests above 1.3 ppb, you have good reason to take action, even if it meets current EPA standards.

Geographic Hotspots: Where Antimony Is Most Common

Antimony contamination isn't evenly distributed across the country. Iowa leads with 253 water systems detecting antimony above guideline levels, followed by West Virginia (107 systems), South Dakota (100), Louisiana (83), and New York (80). These patterns reflect both geology and industrial history.

Iowa's high numbers relate to natural mineral deposits combined with agricultural and mining activities. West Virginia and Kentucky's coal mining heritage contributes to elevated levels. The Midwest's reliance on groundwater wells — rather than surface water — also means more exposure to naturally occurring antimony in deep aquifers.

Removing Antimony From Your Water

Antimony requires specific removal methods because standard filters don't work well against it. Reverse osmosis systems remove 95-99% of antimony by forcing water through a membrane so fine that antimony molecules can't pass through. Ion exchange systems, which swap contaminants for harmless ions, also effectively reduce antimony levels. Some activated carbon filters can remove certain forms of antimony, though their effectiveness varies.

If your water tests above 1.3 ppb for antimony, a reverse osmosis system under your sink or a whole-home treatment system provides reliable protection. Regular testing — at least annually — helps you confirm your system is working. Echo Water's testing and filtration solutions can identify your antimony levels and recommend the right removal method for your specific water chemistry.

Regulatory Standards for Antimony

Cities With the Highest Antimony Levels

States Most Affected by Antimony

Frequently Asked Questions

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