What are Volatile Organic Compounds (VOCs) in Water?

what are vocs in water

Volatile organic compounds, VOCs for short, are a common type of EPA-regulated drinking water contaminant.

Even today, VOCs can be found in a number of products that are used on a daily basis, like paint thinners, pesticides and insect sprays. VOCs can have nasty human health effects when they’re inhaled – but they’re just as dangerous if they end up in your drinking water supply.

It’s important to be aware of the risks of volatile organic compounds (VOCs), particularly as they’re so widely used, making them a highly likely environmental pollutant in groundwater in the US.

In this guide, I’ll be providing the lowdown on all things VOCs: what they are, how you can test for them in your water, and ultimately, how to eliminate them from your water supply once and for all.

What Are VOCs (Volatile Organic Compounds)?

Volatile organic compounds as usually spoken of in their abbreviated form: VOCs. They’re organic chemicals that are released by a broad range of industrial, agricultural and household products, from paints and solvents to fertilizers and gasoline.

VOCs have very low boiling points, which means that when they’re released into the air and exposed to “normal” temperatures, they’re quick to take on a gas or vapor form. Even when used in temperatures below freezing, VOCs are capable of converting into a gas, which is why they’re known as “volatile” compounds.

Most Common VOCs in Water

Some of the most commonly detected VOCs in water are PCE (perchloroethylene), trihalomethane and MTBE (methyl tert-butyl ether). While you might struggle to speak these spellings out loud, or even read them, it’s worth being aware that these are the three VOCs you’re most likely to come across in your public water supply.

  • PCE (perchloroethylene) is a chemical solvent byproduct, typically used as a degreaser for industrial processes or in dry cleaning applications. You may also find PCE in at-home laundry and dry cleaning products as well as shoe polish and certain solvents.
  • Trihalomethane is perhaps the most common public water VOC of all – and that’s because this chemical is a water disinfection byproduct. All states in the US use chlorine or chloramine to disinfect groundwater supplies and make them safe for consumption. When chlorine is used for the disinfection of water from rivers and lakes, the chlorine merges with organic material and results in the production of trihalomethane. This is a big issue for people who drink from city water supplies, but additionally, if you disinfect private wells with chlorine, you’ll likely face the same problem.
  • Finally, MTBE is now used as a lead substitute to improve the octane reading of gasoline. With such widespread use across the US, it wasn’t long before MTBE started showing up where it wasn’t wanted: in groundwater sources, private wells and city water sources. The main causes of MTBE water contamination are leakages and spillages.
vocs in water

Where Do Volatile Organic Compounds Come From?

VOCs are present in thousands of products that are used on a daily basis. These products, such as gasoline, glues, printer inks, paint, cleaning formulas, varnishes, fuels, paints, glues, permanent markers and much more, are all responsible for the release of high concentrations of VOCs into the air.

If you’re familiar with the distinct whiff you get at the gasoline station or when you remove the lid off a permanent marker, your nose will have already familiarized itself with the smell of VOCs being released from a product. Once a VOC is exposed to air, it’s able to take on a gaseous form immediately.

VOCs don’t just pose an environmental hazard in the air, though – these chemical pollutants are also detected in groundwater and public water supplies.

How Do VOCs Get Into Water?

VOCs aren’t usually naturally occurring – they’re typically a byproduct of human activity. Some of the most common activities that result in VOC contamination in ground water are:

  • Improper VOC disposal leading to groundwater leaching.
  • Chlorine disinfection resulting in chemical reactions that release VOCs as a byproduct.
  • Pollution caused by fuel spillages on the ground or leakage from a storage tank underground resulting in groundwater contamination.

Once VOCs get into a ground water supply, natural environmental occurrences such as precipitation cause these organic chemicals to merge into rivers, streams, and aquifers in private wells, affecting water quality.

Some VOCs, such as those that are released from plants, are naturally occurring, but it’s much more likely that you’ll find VOCs in groundwater sources that are the direct result of a deliberate human behavior or a human-related mistake.

Health Risks Associated With VOCs

A national Total Exposure Assessment Methodology report by the EPA found that around 12 common VOCs were more than twice the issue inside people’s homes than inside – and whether these homes were located in rural or industrial areas made no difference. When the problem is, quite literally, so close to home, it’s easy to see how volatile organic compounds may pose so many human health effects.

Some of the most common potential health effects associated with exposure to VOCs include the following:

Carcinogenic effects

According to the Environmental Working Group, there are currently 12 detected VOCs that are classed as “potentially carcinogenic” – with 9 of these being classified by the EPA. A carcinogenic substance is capable of causing cancer. The 12 carcinogenic VOCs are:

  • Vinyl chloride
  • Benzene (from gasoline)
  • Styrene
  • 1,2,3-Trichloropropane
  • 1,1,2-Trichloroethane
  • Tetrachloroethylene (both PCE and PERC)
  • Trichloroethylene (TCE)
  • 1,4-Dioxane
  • 1,2-Dichloroethane
  • Carbon tetrachloride
  • 1,2-Dichloropropane
  • Dichloromethane (methylene chloride)

Not included in this list, but still important to know about, is MTBE, which has been proven in animal studies to cause tumors in the liver and kidneys.

Neurological Effects

Studies have found that exposure to MTBE in the air or drinking water may have damaging neurological effects, from headaches and nausea to dizziness and even depression.

Health Risk To Organs

VOCs can also pose a health risk to a number of the organs in the human body, including the kidneys and liver. Additionally, certain VOCs have shown the potential to cause nerve damage.

How to Test for VOCs in Water?

It’s important to be aware that VOCs, once waterborne, can affect your water quality without affecting its taste at all. While you can smell VOC chemicals in the air, in liquid form, they present no smell or taste – so you’d never know that you were drinking water VOCs unless you tested for them.

It’s easy to test for VOCs in your water – though testing isn’t cheap. To get a thorough understanding of how many VOCs are in your drinking water, and to what level, you’ll need to arrange for private water testing.

A quick Google search should bring up a number of state-certified laboratories in your local area that can test for water for VOCs like PCE, Trihalomethane and MTBE. You’ll usually be required to send off a sample of your drinking water supply to the laboratory, which will perform thorough testing to determine the quantity of VOCs in your water, and whether this quantity exceeds the suggested national maximum levels by the EPA (more on this below).

Laboratory water testing commonly costs around $100 to $200, but if you believe your health is at risk from VOCs exposure, professional testing might just be your best investment for your family. You may also be able to get a good deal on testing for additional groundwater or public drinking water contaminants, like chlorine and lead, which pose their own health effects that are worth knowing about.

You may have come across “at-home water test” kits online, which also claim to be able to test for many VOCs in your drinking water. I would advise against using an at-home test alone to detect your drinking water VOC levels, as these tests aren’t the most accurate, and won’t give you a clear indication of the problem you’re dealing with.

laboratory water testing

How to Remove VOCs from Drinking Water

The EPA currently regulates 23 VOCs, so if you get your water from a city source, you know that legally, your local authority must make sure that these volatile organic compounds are present in lesser amounts than the EPA’s Maximum Contaminant Level.

If you own a private well and your VOC levels are higher than the Maximum Contaminant Level set by the EPA, it’s essential that you take action and consider investing in water systems that will reduce or remove these chemicals to a safe drinking level.

I’ve highlighted some of the systems to consider for VOCs removal below.

Best Option: Activated Carbon Filters

Activated carbon filters are the most effective solutions for removing VOCs, including benzene and PCE, from drinking water. VOCs are organic compounds – it’s in the name – and that means that they’re carbon-based. For this reason, a carbon filter’s adsorption capabilities are ideally suited for attracting carbon-based VOCs and holding onto these contaminants, like a magnet.

There are no better available water systems than carbon filters for the removal of VOCs. A carbon filtration system may be as small as a refrigerator or pitcher filter and as large as a whole house carbon filter unit. The wide availability of carbon filters means there’s a product for every requirement and every budget.

Carbon filtration systems don’t only have the potential to remove VOCs, either – you can also use these systems to benefit from chlorine and chloramine removal. If you’re looking for clean, safe, better-tasting water at a price that won’t scare you off, a carbon filter offers the full package.

One thing that’s worth checking before you make a purchase, however, is that a carbon filter is capable of removing VOCs. Some filter media is designed to handle a greater quantity of VOCs than others. Look for a product that’s certified for VOCs reduction or removal if you want to be certain that you’re getting a good value for money.

coconut shell carbon

Does Reverse Osmosis Remove VOCs?

You might have heard that reverse osmosis systems are some of the best out there for removing high concentrations of a whole host of EPA-regulated contaminants, including lead, fluoride, chromium and bacteria. But, despite its national reputation for effectiveness as a water treatment solution, there’s no guarantee that this kind of filtration system can remove VOCs from public water supplies.

Make sure the RO system you’re interested in comes with a carbon pre- or post-filter. Without a carbon filter, an RO membrane alone can’t remove VOCs. So, technically, you may as well save your money if you’re only looking for VOC removal, as you only need the carbon filter – the rest of the RO system is an unnecessary extra.

Does Boiling Water Remove VOCs?

No. In fact, boiling drinking water will technically increase the concentrations of VOC as the heat will evaporate some of the water. You would need your own DIY distillation setup to catch the evaporated water particles and send them into a clean chamber – a process that usually takes several hours to create a single batch of water.