What is Trichlorofluoromethane and Why Does It Matter?

Trichlorofluoromethane (also called Freon-11 or CFC-11) is a synthetic chemical that was once widely used as a refrigerant and aerosol propellant. It belongs to a family of compounds called chlorofluorocarbons, or CFCs. Industrial facilities, old refrigeration equipment, and improper disposal of aerosol products are the main sources of this chemical. It can enter drinking water supplies through industrial discharge, leaking underground storage, or contamination of groundwater near manufacturing sites. Because it breaks down slowly in the environment, it can persist in water sources long after the original contamination occurred.

Health concerns with trichlorofluoromethane center mainly on the liver, kidneys, and central nervous system. Animal studies show that high-level exposure can cause liver damage and affect the nervous system (according to EPA toxicological data). At lower concentrations — like those found in drinking water — the long-term risks are less clearly defined, but chronic exposure to chlorinated compounds as a class is something researchers continue to study carefully. The EPA classifies trichlorofluoromethane as not classifiable as a human carcinogen based on current evidence, but that doesn't mean it's without concern at elevated levels.

Currently, the EPA has not set a formal Maximum Contaminant Level (MCL) specifically for trichlorofluoromethane in drinking water. It falls under broader monitoring requirements for volatile organic compounds (VOCs) — chemicals that evaporate easily and can move from water into air during activities like showering or boiling. The good news is that across the 23 water systems where this compound was detected, none reported levels above health guidelines. The average detected level was 2.172 parts per billion (ppb), with a maximum detection of 40.7 ppb. That maximum is worth noting — even without a formal violation, a level that far above the average deserves attention from anyone served by that system.

Geographically, New York leads with 6 water systems reporting detections, followed by California with 5 and Wisconsin with 4. Georgia and Washington each reported detections in 2 systems. This pattern makes sense when you consider where older industrial infrastructure, legacy refrigeration facilities, and manufacturing sites are concentrated. New York and California both have dense industrial histories and aging water infrastructure, which creates more opportunities for VOC contamination to reach municipal supplies. Wisconsin's detections likely reflect agricultural and industrial activity in areas with shallow groundwater. If you live in any of these states, it's worth pulling your local water utility's annual Consumer Confidence Report (CCR) to see whether trichlorofluoromethane was detected in your specific system.

The most effective way to remove trichlorofluoromethane from drinking water is through activated carbon filtration or reverse osmosis (RO). Activated carbon works by attracting and trapping VOCs as water passes through, and it's well-suited to this class of chemical. A quality under-sink carbon block filter can significantly reduce VOC levels in your drinking water. For the most thorough protection, a reverse osmosis system removes up to 99% of a broad range of contaminants, including VOCs like trichlorofluoromethane. Echo Water's reverse osmosis systems are designed specifically for this kind of whole-drinking-water protection, filtering what comes out of your tap before it ever reaches your glass. If you're in one of the affected states — especially if your utility reported a detection — adding a point-of-use filter at your kitchen sink is a practical, affordable step you can take today. You don't need to wait for a regulatory limit to be set before protecting your family.

Regulatory Standards for Trichlorofluoromethane

Cities With the Highest Trichlorofluoromethane Levels

States Most Affected by Trichlorofluoromethane

Frequently Asked Questions

Related Contaminant Guides