What is Testosterone and Why Does It Matter?

Testosterone in Tap Water: What You Need to Know

Testosterone is a natural hormone produced by humans and animals. Most people think of it as something made by the body — not something found in drinking water. But testosterone has been detected in 51 water systems across the United States, at concentrations averaging 0.044 parts per trillion (ppt) and reaching as high as 0.275 ppt. It enters the water supply primarily through human and animal waste. Farms, feedlots, and even suburban households contribute to this. When people or livestock excrete hormones, those compounds flow into wastewater systems or runoff into nearby waterways. Standard municipal water treatment wasn't designed to remove hormones, so trace amounts can pass through.

The health picture around testosterone in water is still developing, but researchers have reason to pay attention. Testosterone belongs to a broader class of compounds called endocrine disruptors — chemicals that can interfere with the body's hormonal system. Even at very low levels, some studies suggest these compounds may affect reproductive development, particularly in children and developing fetuses. The Environmental Working Group (EWG) notes that hormone-active substances can disrupt normal biological signaling at concentrations far below what traditional toxicology would consider dangerous. That said, the amounts currently detected in U.S. water supplies are extremely small. No systems in this dataset exceeded established health guidelines. Still, long-term, low-level exposure is an area scientists continue to study closely.

Regulation hasn't caught up with the science here. The EPA does not currently set a legal limit — called a Maximum Contaminant Level (MCL) — for testosterone or most other hormones in drinking water. That means water utilities aren't required to test for it or remove it. The EWG has flagged hormones as an emerging concern, but formal health guidelines specific to testosterone in water remain limited. This regulatory gap is common with newer categories of contaminants. Just because a substance lacks a legal limit doesn't mean it's harmless. It often just means the science is newer and the regulatory process moves slowly.

Geographically, California leads this dataset with testosterone detected in 10 water systems, followed by Illinois with 9, Pennsylvania and Indiana with 4 each, and Michigan with 3. These patterns aren't random. States with large agricultural industries — particularly those with concentrated animal feeding operations (CAFOs) — tend to show higher rates of hormone detection in water. California's massive dairy and livestock sector contributes significant hormone load to local waterways. Illinois and Indiana sit in the heart of the Corn Belt, where large-scale hog and cattle farming is common. Pennsylvania's mix of agricultural runoff and dense suburban development adds another layer of exposure risk. Urban wastewater treatment plants in these states also process large volumes of human waste, which contains naturally excreted hormones.

The good news is that effective filtration options exist. Reverse osmosis (RO) is the most reliable method for removing hormones from drinking water. A quality RO system can remove up to 99% of endocrine-disrupting compounds, including testosterone. Activated carbon filtration also helps, particularly when combined with RO. Standard pitcher filters and basic faucet attachments are generally not effective against hormones at trace levels. If you live in California, Illinois, Indiana, Pennsylvania, or Michigan — or anywhere near large agricultural operations — it's worth taking your filtration setup seriously. Echo Water's reverse osmosis systems are built specifically to address contaminants like these that standard treatment misses. Testing your water first is always a smart starting point. Knowing what's actually in your water lets you choose the right solution rather than guessing.

Regulatory Standards for Testosterone

Cities With the Highest Testosterone Levels

States Most Affected by Testosterone

Frequently Asked Questions

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