1,2-Dichloroethane in Drinking Water: Complete Guide (2026)

What is 1,2-Dichloroethane and Why Does It Matter?

# 1,2-Dichloroethane: What You Need to Know About This Industrial Chemical

1,2-Dichloroethane is a colorless liquid chemical used primarily in manufacturing vinyl chloride, a plastic ingredient found in everything from pipes to medical equipment. It also shows up in some dry cleaning solvents and as a degreaser in industrial settings. When facilities that handle this chemical aren't properly regulated or maintained, it leaks into groundwater and eventually reaches municipal water supplies. Once in the environment, it's highly persistent—meaning it doesn't break down easily and can contaminate drinking water for years. Our analysis found 1,2-dichloroethane in 96 water systems across the United States, with 25 of those systems exceeding health guidelines.

The chemical's health effects depend on how much exposure you receive and for how long. Short-term exposure to high levels can cause dizziness, headaches, and gastrointestinal problems. Long-term exposure is the real concern. The EPA classifies 1,2-dichloroethane as a probable human carcinogen, meaning animal studies suggest it can increase cancer risk (EPA, Integrated Risk Information System). The Environmental Working Group (EWG) estimates that lifetime exposure to this chemical increases cancer risk, which is why their health guideline is stricter than the EPA's standard. In our data, the maximum level detected was 3.68 parts per billion (ppb), and the average across affected systems was 0.37 ppb.

Here's where federal and independent standards diverge. The EPA's legal limit for 1,2-dichloroethane is 5 ppb—the maximum contaminant level (MCL) that all public water systems must meet. However, the EWG's health guideline is 0.35 ppb, based on cancer risk assessment. This means that 25 water systems we identified exceeded the EWG guideline, and some were approaching or at the EPA limit. The EPA's standard protects against acute health effects, but the EWG's stricter threshold aims to minimize long-term cancer risk. If your water system reports 1,2-dichloroethane near or above 5 ppb, you should take action immediately. Even levels below 5 ppb warrant consideration, especially for families with young children or pregnant women, since developing bodies are more vulnerable to chemical exposure.

The geographic pattern here tells an important story. North Carolina leads with 14 affected water systems, followed by New York and Florida with 11 each, California with 8, and Minnesota with 6. These hotspots aren't random. North Carolina and Florida have significant industrial and chemical manufacturing sectors, particularly near coastal areas where groundwater contamination spreads quickly. New York's detections cluster around older industrial regions and areas with legacy dry cleaning operations. California's cases appear in agricultural areas and near manufacturing hubs. Cold-weather states like Minnesota show contamination linked to older industrial sites where groundwater moves slowly, allowing chemicals to persist. If you live in these states—especially near industrial zones, manufacturing facilities, or areas with historical dry cleaning operations—your risk is higher.

Removing 1,2-dichloroethane from your drinking water requires strong filtration. Activated carbon filters work well for this contaminant, but only if they're properly installed and regularly replaced. Reverse osmosis systems are even more effective, removing up to 99.9% of 1,2-dichloroethane and other volatile organic compounds. Boiling won't help—in fact, it can concentrate the chemical. If your water test shows levels above 0.35 ppb, a point-of-use filter on your kitchen tap or a whole-home system makes sense. Have your water tested first to confirm the presence and level of 1,2-dichloroethane. Contact your local water utility for their most recent water quality report, or request a professional water test. Once you know what you're dealing with, you can choose the right filtration solution for your family's protection.

Regulatory Standards for 1,2-Dichloroethane

Cities With the Highest 1,2-Dichloroethane Levels

States Most Affected by 1,2-Dichloroethane

Frequently Asked Questions

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