A health advisory provides information on substances that can cause negative human health effects. Health advisories are non-enforceable and non-regulatory.
The health advisory levels were calculated to offer a margin of protection for all people, including sensitive populations and ages, against adverse health effects and take into account other potential sources of exposure beyond drinking water (for example, food, air, consumer products, etc.). Because these substances have been used in an array of consumer products, most people have been exposed to them and have them in their systems. According to the Centers for Disease Control (CDC), the average concentration (geometric mean) measured in the general U.S. population during 2017-2018 was 1.4 parts per billion (ppb) of PFOA and 4.3 ppb of PFOS. For comparative purposes, this average blood level is 1,400 parts per trillion (ppt) for PFOA when the health advisory in water is 0.004 ppt.