The U.S. Environmental Protection Agency sets standards for water that could affect human health and works with local government officials to reduce health risks in water where you swim or play. You may want to contact your local health deparment or state drinking water office for information specific to your area. Some EPA Web sites you may wish to check are:
- National Primary and Secondary Drinking Water Regulations
- Compilation of National Recommended Water Quality Criteria
- Beach Watch
Another source is the USGS Acute Toxicity Database.