If there’s a dry cleaner anywhere near your well — especially an older one — this article is for you. Perchloroethylene, PCE for short, is the dry-cleaning solvent, and it has a long history of finding its way into groundwater.
What it is. Perchloroethylene (also called tetrachloroethylene, PCE, or “perc”) is a manufactured chlorinated solvent — a clear, colorless liquid that evaporates easily and carries a mild, sweet, chloroform-like odor. It is used mostly in dry cleaning and textile processing, with smaller uses in metal degreasing and chemical manufacturing. Like its cousins TCE and vinyl chloride, it’s a volatile organic compound — and like them, it’s denser than water, so spilled PCE sinks deep into aquifers and lingers for decades.
Where it comes from. Dry cleaners, first and foremost — decades of small spills, leaky machines, and improper disposal add up. Metal degreasing shops, chemical plants, and old industrial sites round out the list. And here’s the family connection: PCE breaks down very slowly underground into TCE, then into dichloroethylene (DCE), and then into vinyl chloride — so a PCE plume can generate its more dangerous relatives over time.
The health picture, honestly. The EPA’s health goal (MCLG) for PCE is zero, because the EPA classifies PCE as likely to be carcinogenic to humans. The legally enforceable limit (MCL) is 0.005 mg/L — 5 parts per billion. Drinking water with PCE above that limit over many years could lead to liver problems and an increased risk of cancer. Short-term exposure to high concentrations can affect the nervous system. And because PCE is volatile, showering and bathing add inhalation to the exposure — which is why this one is a whole-house conversation, not just a kitchen-sink one.
How to test. A lab VOC test (EPA Method 524.2) from a state-certified drinking water laboratory — basic home test strips will not work. The lab will give you specialized glass vials designed for volatile organic compounds, so the chemical doesn’t evaporate before analysis. City water folks: check your annual water quality report. Well owners within sight of a dry cleaner — current or long-closed — should test. Old cleaners are the gift that keeps on giving.
What removes it. Granular activated carbon and aeration are the EPA’s best available technologies for PCE. Solid carbon block filters certified for VOC reduction take it out at the tap, and reverse osmosis systems with carbon pre- and post-filters also remove it. At the city scale, treatment plants use air stripping (packed tower aeration) or granular activated carbon.
What does NOT remove it. Standard pitcher filters, basic refrigerator cartridges, and simple sediment filters will not reliably capture PCE. Water softeners, UV, and chlorine don’t remove it either. And boiling is not a fix: PCE evaporates easily, so boiling can drive it out of the water and into the air you breathe. A point-of-use filter at the kitchen sink also leaves the shower untouched — and with a volatile solvent, the shower matters.
What I’d buy: Treatment type: whole-house granular activated carbon filtration at the point of entry, NSF or WQA listed — with aeration ahead of it if your test numbers are high — plus an under-sink carbon block or reverse osmosis system certified for VOC reduction for drinking water. Retest after install and on a schedule; carbon exhausts, and you need to know when.
PCE is the quiet legacy of every strip-mall dry cleaner that ever spilled a bucket. But carbon and aeration take it out reliably. Test if there’s any history near your well, treat the whole house, verify.
Curious what’s in your tap? Start with What’s In Your Water?
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