Protecting Public Health and the Environment.

Drinking Water Health Advisories

The US Environmental Protection Agency (EPA) develops health advisories to provide information on contaminants that can cause human health effects and are known (or anticipated) to occur in drinking water. Health advisories are intended to provide technical guidance to agencies and local officials when contamination situations occur.

Health advisories include levels or limits where health effects are not expected to occur and are updated as necessary. Published health advisory levels are based on non-cancer health effects for specified exposure durations; one-day, ten-day, and lifetime.

One-day and 10-day health advisories are considered acute or short-term levels that are not expected to cause adverse effects for up to one or ten days of exposure. These health advisories are intended to protect a 10-kg (22 pound) child consuming 1 liter of water per day.

Lifetime health advisories are considered chronic or long-term levels that are not expected to cause adverse effects after a lifetime of exposure. These health advisories are intended to protect a 70-kg (154 pound) adult consuming 2 liters of water per day.

Contaminants of Interest

Below is information about a few unregulated contaminants with associated health advisories of current public interest. EPA has finalized over 100 different health advisories.

EPA’s information on drinking water contaminants and health advisories can be found here.

Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS)

Health Advisory Level: 70 ppt or ng/L

To provide Americans, including the most sensitive populations such as children and pregnant women, with a margin of protection from exposure to PFOA and PFOS in drinking water, EPA established health advisory levels for both PFOA and PFOS at 70 parts per trillion (ppt). When these two chemicals are found in drinking water, the combined concentrations should be compared with the health advisory level.

EPA’s health advisory information for PFOA and PFOS is found here.

What are PFOA and PFOS?

PFOA and PFOS are fluorinated organic chemicals that are part of the perfluoroalkyl family and polyfluoroalkyl substances (PFAS) that do not occur naturally in the environment. These chemicals have been used to make carpets, clothing, fabrics for furniture, and paper packaging for food and other materials (e.g., cookware) that are resistant to water, grease, or stains. They are also used for firefighting at airfields and in a number of industrial processes. Due to the widespread use of these chemicals, most people have been exposed to them.

While consumer products and food are a large source of exposure to these chemicals for most people, drinking water can be an additional source in the small percentage of communities where these chemicals have contaminated water supplies. Contamination is typically localized and associated with a specific facility such as an industrial facility where these chemicals were produced or used to manufacture other products or an airfield where they were used for firefighting.

Do public water systems monitor for PFOA and PFOS?

Because these contaminants are not regulated, public water systems are not required to monitor for PFOA and PFOS. Idaho adopts EPA’s national primary drinking water standards, and currently, PFOA and PFOS are not regulated contaminants. Some public water systems have participated in EPA’s third round of the Unregulated Contaminant Monitoring Program, and others may have voluntarily collected samples that included testing for PFOA and PFOS. Information and results from the third round of the Unregulated Contaminant Monitoring Rule (UCMR3) is found on EPA's website.

What are the health effects of PFOA and PFOS?

Adverse health effects from PFOA or PFOS depend on the level and length of exposure, and age, lifestyle, and health of the consumer. Adverse health effects may include developmental effects to fetuses during pregnancy or to breastfed infants (e.g., low birth weight, accelerated puberty, and skeletal variations), cancer (e.g., testicular and kidney), liver effects (e.g., tissue damage), immune effects (e.g., antibody production and immunity), thyroid effects, and other effects (e.g., cholesterol changes).

EPA’s health advisory level of 70 ppt was developed based on drinking water consumption of pregnant women who drink water more than other people. The health advisory offers protection against adverse health effects for the most sensitive populations including developing fetuses, breastfed infants, and other children regardless of age and length of exposure. If you or your family are concerned about your health or have symptoms you think may be caused by PFOA or PFOS exposure, discuss your concerns with your healthcare provider.

How do I remove PFAS from my water?

If the PFOA or PFOS level in your drinking water is above the health advisory level, consider using alternate sources of water for drinking or installing a point-of-use device. PFOA and PFOS cannot be removed from water by boiling. Reverse osmosis home filtration units have shown the greatest removal potential. Granular-activated carbon may also be effective in removing PFAS. Point-of-use units can be installed under a sink, or point-of-entry units can be installed at your home’s main water line.

Look for units labeled as effective for removing pesticides and volatile organic compounds. We recommend units certified through third-party organizations that test the units for chemical reduction claims. These units will have a certification label from organizations such as the National Sanitation Foundation, Underwriters Laboratory, and Water Quality Association.

Any type of treatment device requires regular maintenance, such as changing filters, cleaning scale buildup, or disinfecting the unit. Failure to properly maintain a unit reduces its effectiveness and, in some cases, may make the water quality worse. Continued maintenance is necessary for the life of the device along with regular water testing to ensure the device is working properly. Follow the manufacturer’s recommendations for replacements and maintenance.

Can I cook with the water?

If the PFOA or PFOS level in your water is above the health advisory level, consider using alternate sources of water for foods where the water is absorbed or consumed such as soups, rice, and beans. Tap water may be used to wash produce and dishes as very little of this water will be consumed.

Can I use the water for showering and bathing?

PFOA and PFOS do not easily enter the body through the skin. Bathing, swimming, and showering with water that has PFOA or PFOS levels above the health advisory values is safe.

Can I use the water for laundry?

Very little water remains on clothing and fabric that has been washed. You may use water with PFOA or PFOS levels above the health advisory values for general cleaning and washing your clothing, bedding, and linens.

Can I use the water in a humidifier?

If the PFOA or PFOS level in your water is above the health advisory level, use distilled or treated water in your humidifier.

Can my pets drink the water?

The health effects from PFOA and PFOS on animals are probably similar to the effects on people. If the PFOA or PFOS level in your water is above the health advisory level, or you are concerned about your pet’s health, use bottled or treated water for drinking and food preparation.

Can I use the water for my garden?

At this time, we do not have adequate information to advise. Based on limited information, root vegetables and leafy vegetables may take in PFAS from water and the soil they are grown in, but other types of produce such as grains and fruits may take in less PFAS. Peeling root vegetables may reduce the amount of chemicals that could cling to the vegetables.

Where do I get my water tested?

Laboratories certified to test for PFAS (EPA Method 537) are listed here. Please note laboratories can only analyze PFC samples if the box “EPA 537” is marked with "X" next to their names. 

Staff Contacts

Drinking Water Program Analyst
Megan Larson
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0475

Additional Resources

DrinkTap: Perfluorinated Compounds

Agency for Toxic Substances and Disease Registry: Per- and Polyfluoroalkyl Substances and Your Health

Related Pages

Blue-Green Algae and Harmful Algal Blooms: Information for Public Water Systems