VOCs, Pesticides, and Herbicides: Problems and Solutions


Volatile Organic Compounds, or VOCs, are chemical contaminants that find their way into our water from agricultural or industrial runoff. 

VOCs are found in a wide variety of commercial, industrial and residential products including fuel oils, gasoline, solvents, cleaners and degreasers, paints, inks, dyes, refrigerants and pesticides. They are carbon-containing compounds that evaporate easily from water into air at normal air temperatures.

People are most commonly exposed to VOCs through the air, in food, through skin contact, and in drinking water supplies. The U.S. Environmental Protection Agency (EPA) estimates that VOCs are present in one-fifth of the nation's water supplies.

How do VOCs end up in drinking water?

Most VOCs in the environment are the result of human activities. When VOCs are spilled or disposed of improperly, while some evaporates, a portion seeps into the ground. Rain may drag VOCs deeper into the soil, and eventually into ground water. When VOCs travel to nearby wells, they ultimately end up in drinking water supplies.

Another source of VOCs in the water supply is municipal treatment systems. When chlorination agents used for disinfection come into contact with naturally occurring organic materials in the source water, the process generates compounds called trihalomethanes (THMs).

A VOC of growing environmental concern is methyl-tertiary-butyl-ether (MtBE). MtBE is used as an oxygenate in gasoline to reduce air pollution. This chemical is so readily dissolved in water that it takes less than a teaspoonful of MtBE to contaminate an Olympic-sized swimming pool.

Should I worry about VOCs?

VOCs have numerous negative health effects. At high levels of exposure, VOCs can affect the central nervous system, the kidneys and the liver. Some VOCs are considered carcinogens (cancer causers). The EPA has stated drinking water standards for 23 VOC compounds.

How can I find out if my water has VOCs?

At high concentrations, some VOCs are identifiable by an unpleasant odor. Unfortunately, VOCs may be a health concern at much lower levels. It is important to determine their existence in the water (even if only in minute quantities) in order to verify the appropriate treatment.

The EPA has established Maximum Contaminant Levels (MCLs) - the maximum allowable level for a contaminant in drinking water - for approximately 25 VOCs, and also requires municipalities test for other unregulated VOCs on a regular basis. While public water systems are monitored on a routine basis for contamination, for private wells, it is the homeowner's responsibility to regularly evaluate water quality.

What VOC water treatment options do I have?

Water treatment systems can effectively reduce VOCs. When choosing a system, be sure to select one specifically certified to reduce VOCs.

Filtration systems may be installed for point-of-entry (POE) treatment where water enters the home, or point-of-use treatment (for example, drinking water faucets or showers.) Because VOCs may enter the body through skin absorption or through inhalation of water vapor, POE systems are preferred as they provide safe water for bathing and laundry, as well as for cooking and drinking.

Home filtration systems utilizing activated carbon filters can reduce VOCs if they are installed and managed properly. Granular activated carbon filters are typically used for drinking water.

Water treatment systems should be checked regularly to confirm they are operating properly. It is extremely important to change carbon filters on the recommended schedule, because once carbon is exhausted it can start to add the VOCs it was reducing. It is also important to periodically test the water before and after the filter to ensure proper filter function.

VOC Treatment Recommendations