What is Trichloroethylene* and Why Does It Matter?

Trichloroethylene (TCE) is a colorless industrial solvent with a sweet, chloroform-like smell. For decades, manufacturers used it to clean metal parts, degrease machinery, and produce other chemicals. It doesn't stay put. TCE evaporates easily, seeps into soil, and eventually works its way into groundwater — the same groundwater many communities drink. Military bases, dry cleaners, and old manufacturing sites are among the most common sources of TCE contamination in drinking water supplies.

The health concerns around TCE are serious and well-documented. The EPA classifies it as a known human carcinogen, meaning there's strong evidence it causes cancer — particularly kidney cancer — with long-term exposure. The National Toxicology Program also links TCE to liver damage and immune system effects. Pregnant women face additional risks: studies show TCE exposure during pregnancy may cause heart defects in developing fetuses. Even at low levels, long-term exposure adds up. That's why the EWG's health guideline sits at just 0.1 ppb — a number based on what scientists consider genuinely protective, not just legally acceptable.

Here's where the regulatory gap becomes important. The EPA's legal limit for TCE in drinking water is 5 ppb. The EWG health guideline is 0.1 ppb — 50 times stricter. Of the 74 water systems that detected TCE across the country, 15 reported levels above that EWG guideline. The average detected level was 0.271 ppb, and the highest recorded level hit 1.68 ppb — more than 16 times above what the EWG considers safe. A water system can report TCE and still be in full legal compliance with the EPA, even when levels exceed health-based recommendations. That's a gap worth understanding.

Geography matters when it comes to TCE. California leads all states with 12 affected water systems, followed by New York with 9, Washington with 6, Alabama with 6, and Arizona with 5. These patterns aren't random. California and Washington both have long histories of aerospace and defense manufacturing, industries that relied heavily on TCE as a degreaser. New York's contamination often traces back to older industrial corridors and Superfund sites — areas where chemical cleanup is still ongoing. Arizona's dry climate means communities depend heavily on groundwater, making aquifer contamination especially difficult to avoid. Alabama's numbers likely reflect a mix of military installations and legacy manufacturing facilities scattered across the state.

The good news is that TCE is very effectively removed by the right filtration technology. Activated carbon filters can reduce TCE, but reverse osmosis (RO) systems are the most reliable option for home use. A quality RO system removes up to 99% of TCE from drinking water, bringing levels well below even the strictest health guidelines. Echo Water's reverse osmosis systems are designed specifically to handle contaminants like TCE — the kind that slip through legal limits but still pose real health risks. If you're in California, New York, Washington, Alabama, or Arizona, it's worth pulling your local water quality report and checking TCE levels directly. You can also request an independent water test if you want a clearer picture of what's coming out of your tap. Knowing your numbers is always the first step.

Regulatory Standards for Trichloroethylene*

Cities With the Highest Trichloroethylene* Levels

States Most Affected by Trichloroethylene*

Frequently Asked Questions

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