In recent years, the presence of water contaminants such as perfluorooctane sulfonate, also known as PFOS, has increased. Commonly found in many stain barrier products, PFOS has been proven to be harmful to human health, even from short-term exposure. Whether you're on well water or the city water supply, you need to understand the dangers of PFOS, how you test for it, and the PFOS treatment you can use to minimize it in your home's water.