Volatile Organic Compounds (VOCs): Examples, Risks & Water

Volatile organic compounds, commonly called VOCs, are a broad group of carbon-containing chemicals that can readily enter the air as gases. Some can also contaminate groundwater or drinking-water supplies.

You may encounter VOCs from paint, solvents, gasoline, cleaning products, building materials, dry-cleaning chemicals, industrial activity, fuel leaks, and certain drinking-water treatment byproducts.

This guide explains what VOCs are, common examples, where exposure can occur, how VOCs can enter drinking water, and practical ways to reduce exposure at home.

What Are Volatile Organic Compounds?

Volatile organic compounds are organic chemicals that tend to evaporate relatively easily under ordinary environmental conditions.

This volatility explains why opening a container of paint thinner, gasoline, adhesive, or certain cleaning products can quickly create a noticeable smell.

However, odor is not a reliable measure of exposure or risk. Some VOCs can be detected by smell at low concentrations, while others may be present without a noticeable odor.

VOCs can come from both natural and human-made sources.

Natural sources include plants and biological processes. Human-made sources include:

• Fuels
• Solvents
• Paints and coatings
• Industrial processes
• Building materials
• Cleaning products
• Combustion
• Chemical spills and waste

VOCs in Air vs. VOCs in Water

One of the most useful distinctions is between VOC exposure through air and VOC contamination of water.

The same chemical can sometimes be relevant to more than one route of exposure.

For example, a volatile solvent in contaminated groundwater may be consumed in drinking water and may also transfer from water into indoor air during showering or other household use.

Common Sources of VOCs Indoors

Many VOC exposures occur inside homes, offices, workshops, and other buildings.

Potential sources include:

• Paints, stains, varnishes, and coatings
• Paint strippers
• Adhesives and sealants
• Pressed-wood furniture and cabinetry
• Some flooring products
• Cleaning and disinfecting products
• Air fresheners
• Aerosol sprays
• Craft and hobby supplies
• Permanent markers
• Dry-cleaned clothing
• Tobacco smoke
• Stored gasoline or fuel
• Printers and some office equipment

Indoor concentrations can increase when VOC-emitting products are used in enclosed areas with inadequate ventilation.

Outdoor and Industrial Sources of VOCs

VOCs are also released outdoors through transportation, industrial processes, fuel handling, and combustion.

Examples include:

• Vehicle exhaust and fuel evaporation
• Gasoline stations and storage facilities
• Industrial emissions
• Manufacturing
• Petroleum refining
• Solvent use
• Paint and coating operations
• Wildfire and biomass smoke

Some VOCs also contribute to atmospheric chemistry that leads to ground-level ozone and smog.

How Do VOCs Get Into Drinking Water?

VOCs can enter groundwater, surface water, or drinking-water systems through several pathways.

Potential sources include:

• Leaking underground fuel tanks
• Gasoline and petroleum spills
• Industrial solvent releases
• Improper chemical disposal
• Landfill leachate
• Contaminated industrial sites
• Leaking storage areas
• Certain water-treatment byproducts

Groundwater can be particularly vulnerable to certain VOCs because surface-spilled chemicals can move through soil and reach aquifers.

Once contamination reaches groundwater, it may persist and travel with groundwater flow.

Common Examples of VOCs

Are All VOCs Dangerous?

No.

The term VOC describes a broad chemical characteristic. It is not itself a toxicity rating.

The health significance of a VOC depends on:

• The specific compound
• Concentration
• Duration of exposure
• Frequency of exposure
• Whether exposure occurs through air, water, skin contact, or another route
• Individual susceptibility

Some VOCs mainly cause temporary irritation at elevated concentrations. Others have been associated with neurological, liver, kidney, reproductive, developmental, or cancer risks.

Possible Health Effects of VOC Exposure

Health effects depend heavily on the chemical and exposure level.

Short-Term Exposure

High short-term exposure to certain VOCs can contribute to symptoms such as:

• Eye irritation
• Nose or throat irritation
• Headache
• Dizziness
• Nausea
• Fatigue
• Loss of coordination at sufficiently high exposures

These effects are particularly relevant when solvent-containing products are used in poorly ventilated spaces.

Long-Term Exposure

Long-term health concerns vary much more by compound.

Certain VOCs have been associated with effects involving:

• The nervous system
• Liver
• Kidneys
• Blood and bone marrow
• Respiratory system
• Reproductive or developmental systems
• Cancer risk

Those effects should not be generalized to every VOC. Risk assessment must consider the individual chemical and actual exposure.

Who May Be More Vulnerable?

Individual sensitivity can vary.

People who may warrant additional attention around environmental exposures can include:

• Children
• Older adults
• Pregnant people
• People with asthma or other respiratory conditions
• Workers using solvents regularly
• People with medical conditions that increase vulnerability to particular chemicals

However, the most useful response is generally to identify and reduce unnecessary exposure rather than assuming that every detectable VOC poses the same danger.

How to Reduce VOC Exposure Indoors

Improve Ventilation

Ventilation can help prevent VOCs from accumulating indoors.

When appropriate, open windows and doors, use exhaust ventilation, and increase airflow when using products such as paint, stains, solvents, adhesives, or strong cleaners.

Follow Product Instructions

Use products only as directed on the label, including any requirements for protective equipment or ventilation.

Do not assume that a household product is harmless simply because it is commonly sold.

Choose Lower-Emission Products

Low-VOC or lower-emission paints, coatings, adhesives, and building materials can reduce indoor emissions compared with some conventional alternatives.

However, “low VOC” does not mean that a product contains no potentially irritating or hazardous substances.

Store Chemicals Properly

Keep:

• Gasoline
• Paint
• Solvents
• Paint thinner
• Strong cleaners
• Automotive chemicals

tightly closed and stored according to manufacturer instructions, preferably away from occupied living areas when appropriate.

Dispose of Unneeded Chemicals Properly

Do not pour fuels, solvents, paint, or hazardous chemicals down household drains or onto the ground.

Use local household hazardous-waste programs where available.

What Does “Low VOC” Mean?

“Low VOC” labels can be useful when comparing certain products, but they require context.

VOC definitions and limits can vary by product category and regulatory program.

A low-VOC paint, for example, may emit fewer regulated VOCs than another paint but can still contain other ingredients that have odors or health considerations.

So product selection should combine:

• VOC information
• Manufacturer instructions
• Ventilation
• Appropriate protective measures

VOCs in Drinking Water

Although VOCs are often discussed as air pollutants, some are also important drinking-water contaminants.

Examples that may be relevant to water include:

• Benzene
• Toluene
• Trichloroethylene
• Tetrachloroethylene
• Vinyl chloride
• Carbon tetrachloride
• Dichloromethane
• Various chlorinated solvents

Public water systems monitor regulated contaminants in accordance with applicable federal and state requirements.

Your annual Consumer Confidence Report is a useful starting point for understanding what has been detected in your public drinking water supply.

Private well owners have a different responsibility because municipal utilities do not routinely monitor well water.

VOCs and Private Wells

VOC testing may be especially worth considering when a private well is located near:

• Gas stations
• Fuel storage areas
• Industrial properties
• Dry cleaners
• Landfills
• Known contaminated sites
• Areas with documented solvent spills

Testing should be performed by an appropriate laboratory using methods designed for volatile compounds.

Because VOCs can evaporate easily, sample collection and handling are particularly important.

If you use a private well, see our well-water testing and treatment guide for broader information about water-quality testing.

Can You Smell VOCs in Drinking Water?

Sometimes—but smell should not be used as a reliable water-quality test.

Some volatile chemicals can produce noticeable odors of solvents, fuel, or chemicals. Others may be present at concentrations that are not easily detected by smell.

Likewise, detecting an odor does not tell you which chemical is present or its concentration.

If water suddenly develops a gasoline-like, solvent-like, or unusual chemical odor, stop relying on smell alone and contact the appropriate water utility, health agency, or laboratory for guidance.

Can VOCs Move From Water Into Indoor Air?

Because VOCs are volatile, some can transfer from contaminated water into indoor air.

This may occur during activities such as:

• Showering
• Bathing
• Cooking
• Running hot water
• Washing dishes

This means that when substantial VOC contamination affects household water, exposure may not be limited to drinking the water.

For that reason, a significant confirmed VOC problem may require a broader evaluation than simply treating a single glass of drinking water.

Are Trihalomethanes VOCs?

Several trihalomethanes are volatile organic compounds.

Trihalomethanes, or THMs, can form when chlorine or other chlorine-based disinfectants react with naturally occurring organic material in source water.

Common regulated THMs include:

• Chloroform
• Bromodichloromethane
• Dibromochloromethane
• Bromoform

The four are commonly regulated together as total trihalomethanes, or TTHMs.

This is different from VOC contamination caused by a leaking fuel tank or industrial solvent spill, even though both situations involve volatile organic chemicals.

How Are VOCs in Drinking Water Regulated?

EPA has enforceable primary drinking-water standards for several individual VOCs in public water systems.

Examples include:

• Benzene
• Trichloroethylene
• Tetrachloroethylene
• Vinyl chloride
• Toluene
• Xylenes
• Carbon tetrachloride
• Dichloromethane

The important point is that EPA does not regulate “VOCs” as though they are a single substance. Individual chemicals have different standards based on their toxicology and other considerations.

How Do You Test Water for VOCs?

If VOC contamination is suspected, laboratory analysis is the appropriate approach.

A certified or otherwise qualified drinking-water laboratory can advise which VOC panel is appropriate.

Testing becomes particularly relevant when:

• A nearby fuel spill has occurred
• A dry cleaner or industrial facility has affected local groundwater
• A government agency has identified a contaminated site nearby
• Your well develops a chemical or fuel-like odor
• Previous testing has detected VOCs

Can Activated Carbon Reduce VOCs?

Activated carbon is one of the most commonly used technologies for reducing the levels of many organic chemicals in drinking water.

Carbon contains a large internal surface area that can adsorb many compounds as water passes through the media.

But performance varies significantly according to:

• The specific VOC
• Type of activated carbon
• Amount of carbon
• Contact time
• Flow rate
• Competing organic compounds
• Incoming concentration
• Filter age

For that reason, the statement “activated carbon removes VOCs” is too broad.

A better question is: Has this particular filter demonstrated a reduction in the VOC I'm concerned about?

Granular Activated Carbon vs. Carbon Block

Activated carbon is available in several configurations.

Granular Activated Carbon

Granular activated carbon, or GAC, consists of loose carbon particles.

Large GAC treatment vessels are widely used for organic contaminant treatment because they can provide significant amounts of carbon and contact time.

Carbon Block and Composite Filters

Carbon can also be incorporated into compressed blocks or proprietary composite filter elements.

Actual contaminant reduction depends on the entire design—not simply the presence of carbon.

Can Reverse Osmosis Reduce VOCs?

Reverse osmosis systems can reduce certain organic compounds, but membrane performance varies by chemical.

For this reason, residential RO systems commonly incorporate activated-carbon stages as part of the treatment train.

The carbon and membrane stages can complement one another.

If you're comparing treatment methods, our Types of Drinking Water Filtration Systems guide explains activated carbon, RO, gravity filtration, distillation, UV, and other approaches.

Why Boiling Is Not a Good General VOC Treatment

Boiling should not be used as a general household strategy for solving VOC contamination.

Because VOCs are volatile, heating contaminated water can cause certain compounds to transfer from water into indoor air.

Boiling also provides no reliable way for a homeowner to verify the contaminant's final concentration.

Does Distillation Reduce VOCs?

Distillation requires special caution when handling volatile contaminants.

Standard distillation works well for many nonvolatile dissolved substances because water is vaporized and recondensed while the contaminants remain behind.

But some volatile organic compounds can also vaporize.

For that reason, a basic distillation process should not automatically be assumed to remove every VOC unless the treatment system is specifically designed for that contaminant, potentially with additional stages such as activated carbon.

Berkey® Filters and VOCs

Berkey® gravity-fed systems are countertop vessels. Their contaminant-reduction performance depends on the specific filter elements installed.

This distinction is important because the stainless-steel Berkey® chamber itself does not determine VOC reduction.

If VOC reduction is one of your goals, review the current performance information for the individual filter element.

Black Berkey® Elements

Black Berkey® Elements use proprietary filtration media and are designed to reduce the levels of various organic chemicals.

For any specific VOC concern, compare the contaminant identified in your water report or laboratory analysis with current performance information for the Black Berkey® Elements rather than relying on a general “VOC” claim.

Phoenix Gravity New Millennium Edition™ Filters

Phoenix Gravity New Millennium Edition™ filters use coconut-shell activated carbon media and are designed for municipal drinking-water applications.

Available testing includes reduction performance for selected VOCs and other organic compounds.

You can review the available results on our Water Filter Test Results page.

Point-of-Use vs. Whole-House VOC Treatment

If VOCs have been confirmed in the water entering your home, it is worth considering whether treatment is needed only for drinking water or for all household water.

A point-of-use system treats water at one location, such as the kitchen.

A point-of-entry system treats water before it is distributed throughout the building.

This distinction can matter for highly volatile contaminants, as VOCs may enter indoor air during showering and other activities.

A significant confirmed contamination problem may therefore warrant evaluation by an experienced water-treatment or environmental professional rather than relying solely on countertop filtration.

How to Choose a Water Filter for VOCs

A practical process is:

1. Identify the contaminant. Use your water report or laboratory testing.
2. Determine the concentration.
3. Check the treatment technology. Activated carbon is common, but not every VOC behaves the same way.
4. Review documented reduction performance.
5. Determine whether point-of-use treatment is sufficient.
6. Follow the specified filter replacement schedule.
7. Retest when appropriate.

How to Reduce VOC Exposure Overall

VOCs are part of modern life, so eliminating every possible exposure is neither practical nor necessary.

A more useful approach is to reduce avoidable exposure from significant sources.

That can include:

• Providing adequate ventilation when using solvents or coatings
• Choosing lower-emission products where practical
• Storing fuels and solvents properly
• Removing unnecessary chemical products from living spaces
• Following workplace safety requirements
• Disposing of hazardous household chemicals responsibly
• Reviewing local drinking-water reports
• Testing private wells when contamination is plausible

FAQ: Volatile Organic Compounds

The Bottom Line

Volatile organic compounds are a broad group of chemicals found in everyday products, fuels, industrial processes, building materials, air, and sometimes drinking water.

The term VOC does not describe a single contaminant or a single level of health risk.

Some VOCs become a concern only at high indoor concentrations, while others—such as benzene, vinyl chloride, TCE, and PCE—are regulated in drinking water due to more serious long-term health concerns.

At home, reducing unnecessary exposure often starts with simple measures: ventilation, careful chemical storage, appropriate product use, and responsible disposal.

For drinking water, the process should begin with identification. Review your water-quality report or obtain laboratory testing when there is a reason to suspect VOC contamination.

Once you know what is present, choose treatment based on documented reduction performance for that specific compound rather than relying on a broad promise that a filter “removes VOCs.”