cis-1,2-Dichloroethylene
cis-DCE·Affects liver, heart
An industrial solvent and breakdown product of trichloroethylene (TCE). Found in groundwater near industrial sites, dry cleaners, and Superfund areas.
cis-DCE
EPA limit
0.07 mg/L (MCL)
Most at risk
Households near industrial sites, dry cleaners, or known TCE plumes
Found in
City water · Well water · Industrial areas
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
cis-1,2-Dichloroethylene primarily targets the liver and the cardiovascular system. Chronic exposure in animal studies shows liver damage, immune system suppression, and changes to red blood cell counts. It is one of two geometric isomers of 1,2-DCE (the other being trans-1,2-DCE); the cis form is more commonly detected in drinking water and is regulated at a lower level.
Unlike its parent compound TCE, cis-DCE is not currently classified as a probable human carcinogen by the EPA, but the toxicological data is limited and chronic effects are not fully characterized.
The EPA's limit of 70 ppb is set with a safety factor below the lowest observed adverse effect level in animal studies.
Where it comes from
How it gets into your water
cis-1,2-DCE rarely shows up as a primary contaminant. It almost always appears as a breakdown product of more dangerous chlorinated solvents like trichloroethylene (TCE) and tetrachloroethylene (PCE). When those compounds leak into groundwater, naturally-occurring soil bacteria break them down sequentially, and cis-DCE is one of the intermediate products.
The implication: if cis-DCE shows up in your water, there is likely a larger plume of related solvents nearby. Common sources include dry cleaners (PCE), metal degreasing operations (TCE), and electronics manufacturing.
Industrial sites
Metal degreasing, electronics, manufacturing
Dry cleaners
PCE breakdown in groundwater
Contaminated wells
Often near known TCE/PCE plumes
Find out for yourself
Is it in your water?
cis-1,2-DCE is on the EPA's regulated contaminant list, so all public water utilities test for it. It is usually undetected. If you see it on your Consumer Confidence Report, the utility is also probably reporting elevated TCE or PCE nearby.
Private well owners in industrial corridors, near current or former dry cleaners, or within a few miles of a Superfund site should specifically request VOC testing including cis-DCE, TCE, and PCE. State drinking-water programs maintain maps of known contamination sites.
The fix
How AquaOx filters it
Activated carbon is the standard treatment for chlorinated solvents including cis-DCE. The Centaur catalytic carbon and coconut shell carbon stages in The AquaOx adsorb these compounds as water flows through, with independent testing showing reductions of more than 95% across the VOC family.
If you have a known industrial plume nearby, we recommend coupling The AquaOx with the under-sink RO at your kitchen tap so drinking and cooking water gets a second-stage polish.
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