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Health information notice: This page covers potential health effects associated with water contaminants. It's general information, not medical advice. Ask your doctor about risks specific to your health history.

Health disclaimer: VOC contamination in drinking water is a serious concern. This page provides general information only, not medical advice. If you suspect VOC contamination in your water supply, contact your state health department and a licensed water testing laboratory.

A USGS study found VOCs in approximately 65% of domestic well samples tested across the US. Most detections were below federal limits. But the prevalence is striking, and it tells you something important: these chemicals are in the ground nearly everywhere industrial and commercial activity has touched.

VOCs aren’t a single contaminant. They’re a class of hundreds of organic chemicals. In drinking water, the concern narrows to a much shorter list, the ones that come from industrial sites, fuel storage, and commercial chemical use.

The VOCs That Actually Matter in Drinking Water

The EPA regulates dozens of VOCs under the Safe Drinking Water Act. A handful come up most often in groundwater contamination cases.

Benzene has an MCL of 5 parts per billion (ppb) and an MCLG of zero. It’s a known carcinogen, associated with leukemia with long-term exposure. The main sources are gas stations, oil refineries, and fracking operations. It’s the compound most commonly found near leaking underground storage tanks.

Trichloroethylene (TCE) also carries an MCL of 5 ppb and an MCLG of zero. It was widely used as an industrial degreaser throughout the 20th century. Long-term exposure is associated with liver damage and non-Hodgkin lymphoma. The EPA classified it as a carcinogenic to humans in 2011. Thousands of industrial and military sites have TCE contamination in their groundwater.

Tetrachloroethylene (PCE or PERC) shares the same MCL of 5 ppb and MCLG of zero. Dry cleaners used it heavily for decades. It’s still in use. PCE is associated with kidney damage and is classified as probably carcinogenic to humans. Former dry cleaning sites and their surrounding neighborhoods frequently show PCE in groundwater.

Vinyl chloride has an MCL of 2 ppb and an MCLG of zero. It’s a known human carcinogen, associated with liver cancer. It doesn’t always come from a direct source, it forms when PCE and TCE break down in groundwater over time. So even sites contaminated decades ago can generate fresh vinyl chloride today.

The MCLGs of zero for all four tell you the EPA’s position: there’s no safe level for long-term exposure.

Where VOCs Come From

The contamination is local. A neighbor’s well a mile away could test clean while yours doesn’t, depending on which direction groundwater flows and what’s between you and the source.

Leaking underground storage tanks (LUSTs) are responsible for a large share of benzene contamination near residential wells. The EPA’s database tracks over 500,000 confirmed releases from underground tanks. Gas stations, auto shops, and fuel distribution facilities are common sites.

Dry cleaners are the primary source of PCE in groundwater. Most cities have several former dry cleaning locations. The PCE soaks into the soil and migrates downward into aquifers, sometimes for decades after the business closed.

Military bases and Superfund sites account for many of the worst TCE contamination cases. The DOD has TCE contamination at hundreds of installations. Some have affected municipal water supplies; others sit near private wells.

Industrial manufacturing sites, chemical plants, and printing facilities also contribute. Agricultural pesticides add to the picture in farming regions, though those tend to involve different compounds.

Municipal vs. Private Well Water

Municipal systems test for VOCs as part of routine compliance with the Safe Drinking Water Act. Your utility is required to notify you if levels exceed MCLs.

Private well owners have no such protection. No federal regulation requires private well testing. If your well is contaminated, you won’t know unless you test.

The risk isn’t evenly distributed. If you’re in a rural area with no industrial activity nearby, your VOC risk is low. If you’re near a gas station, former dry cleaner, old military installation, or Superfund site, testing is worth doing.

How to Test Your Water

A standard VOC panel from a certified lab tests for 50 or more compounds at once. Cost is typically $50 to $150. It covers the major regulated VOCs and many unregulated ones.

Don’t rely on at-home test strips for VOCs. They aren’t sensitive enough for most compounds at the concentrations that matter.

Your state health department can point you to certified labs and may have data on local contamination. The EPA’s Envirofacts database and Superfund site locator can help you identify nearby contamination sources worth knowing about.

If you’re within a mile or two of a gas station, dry cleaner, industrial facility, or old military base, a VOC test is worth the $50 to $150. That’s the direct recommendation here. The test tells you whether you have a problem and which compounds are present, which determines what treatment to install.

Treatment Options

Activated carbon is the primary treatment for most VOCs in drinking water. Granular activated carbon (GAC) filters in whole-house systems can handle high-volume needs. Solid carbon block filters at the point-of-use (under the sink or countertop) work well for drinking and cooking water. Carbon works by adsorbing the VOC molecules onto the carbon surface as water passes through.

Aeration physically strips dissolved VOCs from water by exposing it to air. Point-of-entry aeration systems treat all water entering the house. They’re effective for high concentrations and are commonly used in municipal systems for this reason.

Reverse osmosis paired with a carbon pre-filter gives you the strongest point-of-use protection. RO membranes add a barrier for compounds that carbon doesn’t fully capture, and the combination handles TCE and PCE well. See the best under-sink RO systems for reviewed options.

What doesn’t work: standard pitcher filters without proper carbon media. Boiling. Boiling removes water through evaporation, which concentrates dissolved VOCs rather than removing them. Never boil water as a treatment strategy for chemical contamination.

For mail-in lab options to get your VOC panel done, see best mail-in water tests.

If you’re a well owner unsure where to start, the well water testing guide walks through which tests to prioritize based on your location and local risks.

Sources:

Health disclaimer: WaterAnswer.com provides general information only. If you have concerns about VOC contamination in your water, consult your state health department and a qualified water testing professional.

Frequently Asked Questions

What are VOCs in drinking water?
VOCs (volatile organic compounds) are chemicals that vaporize easily at room temperature. In drinking water, the concern is dissolved VOCs from industrial contamination, things like benzene from gas stations, TCE from industrial degreasers, and PCE from dry cleaners. They enter groundwater when spills or leaks work their way down through soil into an aquifer.
Are VOCs in well water dangerous?
It depends on the compound and the concentration. The EPA has set the Maximum Contaminant Level Goal (MCLG) at zero for benzene, TCE, PCE, and vinyl chloride, meaning no level is considered safe for long-term exposure. Long-term exposure above the MCLs is associated with liver and kidney damage, central nervous system effects, and various cancers. Most detections in domestic wells are below EPA limits, but proximity to industrial sites raises the risk significantly.
How do I test my water for VOCs?
Order a comprehensive VOC panel from a state-certified lab. Most cost $50 to $150 and test for dozens of compounds at once. Standard at-home test strips don't cover VOCs. Your state health department can recommend certified labs and may know which compounds are most common near industrial sites in your area.
What filter removes VOCs from drinking water?
Activated carbon is the primary treatment for VOCs, both granular activated carbon (GAC) whole-house filters and solid carbon block point-of-use filters work well. Reverse osmosis adds a second layer of protection, especially useful for TCE and PCE. Aeration strips volatile compounds from water before they enter the home and is effective in whole-house systems. Standard pitcher filters without proper carbon media won't do the job.
How do VOCs get into well water?
VOCs enter groundwater through spills, leaks, and improper disposal at the surface. Leaking underground storage tanks at gas stations are a common source. Dry cleaners that used PCE have contaminated soil and groundwater at thousands of sites across the US. Industrial facilities, old military bases, and Superfund sites also contribute. Once in the soil, these compounds dissolve into groundwater and can travel significant distances from the original spill.
Medical disclaimer: WaterAnswer.com provides general information only. Nothing here is medical advice. Consult a licensed healthcare provider before making decisions about your health.