Break out your water filters. A new study by the Environmental Working Group (EWG), published this week in the peer-reviewed journal Heliyon, warns that a potentially “toxic cocktail” of chemicals in U.S. drinking water contributes to increased lifetime risk that adds up to more than 100,000 cases of cancer.

Researchers at the advocacy-focused nonprofit say the findings may help bolster their argument for more environmental protections on U.S. waterways and water systems. They also recommended that concerned consumers use water filters at home to combat the potential risk they face from drinking contaminated water.

Study authors said 87% of the more than 100,000 estimated cancer cases linked to tap water are due to by-products from chemicals used to disinfect it from pollutants such as industrial runoff, untreated sewage and farm fertilizer. Other risks came from naturally occurring arsenic as well as radioactive elements, including uranium and radium, found in some tap water samples.

The study is billed as the first to examine the cumulative cancer risk stemming from 22 carcinogenic chemicals commonly found in the nation’s tap water. The analysis is based on water-quality profiles for more than 48,000 water systems across the country and notes that the cancer risk is present even in the vast majority of the systems they investigated that are in legal compliance with U.S. national drinking water standards.

“Drinking water contains complex mixtures of contaminants, yet government agencies currently assess the health hazards of tap water pollutants one by one,” said EWG science analyst Sydney Evans, lead author of the paper, in a recent statement. “In the real world, people are exposed to combinations of chemicals, so it is important that we start to assess health impacts by looking at the combined effects of multiple pollutants.”

Researchers advised concerned consumers to review the water reports from their communities and choose an appropriate filter to reduce their cancer risk. Fortunately, EWG already has a database and a guide to help people figure both of these things out in practice.

The findings also highlight the need for better water protections that would help protect public health on a population-wide scale. EWG actively advocates for protections such as buffers and cover crops to keep toxic chemicals away from water systems, noting that it’s a lot easier (and cheaper) to prevent the problem than treat it.

To learn more about the links between tap water and cancer, click here.