Human Health Benchmarks
Current testing methods now allow for the detection and measurement of chemicals, such as pharmaceuticals and pesticides, in water at low levels. Low levels of these chemicals measured in drinking water or source water do not necessarily indicate a health risk. Human health benchmarks are drinking water levels based on information about harmful health effects for potential drinking water contaminants. These benchmarks are not rules or regulations and are not enforceable, and they are for contaminants that have no drinking water standards or health advisories. They can be used by states, tribes, public health officials, drinking water systems, and the public to determine if the levels found in water need further investigation. For example, if a pharmaceutical or pesticide occurs in drinking water at levels higher than the benchmark, additional water monitoring or research could be conducted to help ensure protection of Americans’ drinking water.
Human Health Benchmarks for Pharmaceuticals (HHB-Rx)
The U.S. Environmental Protection Agency (EPA), in coordination with the Federal Workgroup on Pharmaceuticals in Water, including the U.S. Department of Agriculture (USDA), U.S. Food and Drug Administration (FDA), and U.S. Geological Survey (USGS), developed human health benchmarks for pharmaceuticals (HHB-Rx) that are approved by the FDA and may occur in source waters (surface and groundwater) and/or treated drinking water. To develop each benchmark, EPA used the lowest oral therapeutic dose from FDA approved labels.
In April 2026, EPA released 374 HHB-Rxs. The HHB-Rx table includes two benchmark values for each pharmaceutical: one for the general population (all ages) and one for infants. EPA may update the HHB-Rx as FDA drug labels change and add benchmarks for additional pharmaceuticals in the future as warranted.
- 2026 Human Health Benchmarks for Pharmaceuticals Table
- Fact Sheet: 2026 Human Health Benchmarks for Pharmaceuticals (pdf)
- Human Health Benchmarks for Pharmaceuticals: 2026 Technical Document (pdf)
- Human Health Benchmarks for Pharmaceuticals: 2026 Technical Support Appendix (xlsx)
- EPA Response to External Peer Review Comments on Human Health Benchmarks for Pharmaceuticals in Drinking Water (pdf)
Human Health Benchmarks for Pesticides (HHBPs)
The 2021 HHBP Table includes benchmarks for 430 pesticides that may be found in surface or ground water sources of drinking water. Noncancer benchmarks for acute (one-day) and chronic (lifetime) drinking water exposures to each pesticide were derived for the most sensitive life stage based on the available information. The table also includes cancer benchmarks for 48 of the pesticides that have toxicity information that indicates the potential to lead to cancer.