Basic Information about Xylenes in Drinking Water
Xylenes at a Glance
Maximum Contaminant Level (MCL) = 10 milligrams per Liter (mg/L) or 10 parts per million (ppm)
Maximum Contaminant Level Goal (MGLG) = 10 mg/L or 10 ppm
Some people who drink water containing xylenes in excess of the MCL over many years could experience damage to their nervous system.
Chemical Abstract Service Registry
Sources of Contamination
Discharge from petroleum factories; discharge from chemical factories
EPA regulates xylenes in drinking water to protect public health. Xylenes may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by EPA.
- What is xylenes?
- Uses for xylenes.
- What are xylenes's health effects?
- What are EPA's drinking water regulations for xylenes?
- How does xylenes get into my drinking water?
- How will I know if xylenes is in my drinking water?
- How will xylenes be removed from my drinking water?
- How do I learn more about my drinking water?
Uses for xylenes.
The greatest use of xylenes is as a solvent which is much safer than benzene. Other uses include: in gasoline as part of the BTX component (benzene-toluene-xylene); Xylene mixtures are used to make phthalate plasticizers, polyester fiber, film and fabricated items.
If you are concerned about xylenes in a private well, please visit:
This health effects language is not intended to catalog all possible health effects for xylenes. Rather, it is intended to inform consumers of some of the possible health effects associated with xylenes in drinking water when the rule was finalized.
What are EPA's drinking water regulations for xylenes?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur. These non-enforceable health goals, based solely on possible health risks and exposure over a lifetime with an adequate margin of safety, are called maximum contaminant level goals (MCLG). Contaminants are any physical, chemical, biological or radiological substances or matter in water.
The MCLG for xylenes is 10 mg/L or 10 ppm. EPA has set this level of protection based on the best available science to prevent potential health problems. EPA has set an enforceable regulation for xylenes, called a maximum contaminant level (MCL), at 10 mg/L or 10 ppm. MCLs are set as close to the health goals as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies. In this case, the MCL equals the MCLG, because analytical methods or treatment technology do not pose any limitation.
The Phase II Rule, the regulation for xylenes, became effective in 1992. The Safe Drinking Water Act requires EPA to periodically review the national primary drinking water regulation for each contaminant and revise the regulation, if appropriate. EPA reviewed xylenes as part of the Six Year Review and determined that the 10 mg/L or 10 ppm MCLG and 10 mg/L or 10 ppm MCL for xylenes are still protective of human health.
States may set more stringent drinking water MCLGs and MCLs for xylenes than EPA.
A federal law called the Emergency Planning and Community Right to Know Act (EPCRA) requires facilities in certain industries, which manufacture, process, or use significant amounts of toxic chemicals, to report annually on their releases of these chemicals. For more information on the uses and releases of chemicals in your state, contact the Community Right-to-Know Hotline: (800) 424-9346.
- EPA's Toxics Release Inventory (TRI) Web site provides information about the types and amounts of toxic chemicals that are released each year to the air, water, and land.
How will I know if xylenes is in my drinking water?
When routine monitoring indicates that xylenes levels are above the MCL, your water supplier must take steps to reduce the amount of xylenes so that it is below that level. Water suppliers must notify their customers as soon as practical, but no later than 30 days after the system learns of the violation. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.
If your water comes from a household well, check with your health department or local water systems that use ground water for information on contaminants of concern in your area.
How will xylenes be removed from my drinking water?
The following treatment method(s) have proven to be effective for removing xylenes to below 10 mg/L or 10 ppm: granular activated carbon combined with packed tower aeration.
How do I learn more about my drinking water?
EPA strongly encourages people to learn more about their drinking water, and to support local efforts to protect the supply of safe drinking water and upgrade the community water system. Your water bill or telephone book's government listings are a good starting point for local information.
Contact your water utility. EPA requires all community water systems to prepare and deliver an annual consumer confidence report (CCR) (sometimes called a water quality report) for their customers by July 1 of each year. If your water provider is not a community water system, or if you have a private water supply, request a copy from a nearby community water system.
Other EPA Web sites
- Find an answer or ask a question about drinking water contaminants on EPA's Question and Answer Web site or call EPA's Safe Drinking Water Hotline at (800) 426-4791
- EPA's Integrated Risk Information System
- EPA's Substance Registry System
- EPA's Technology Transfer Network Air Toxics website, Xylenes
Other Federal Departments and Agencies