Most Dangerous Contaminants

Information about common water contaminants and their health effects

Laboratory water testing

This information is provided for educational purposes. If you're concerned about contaminants in your water,check your local water quality or contact your water utility.

Lead

Sources:

Old pipes, solder, brass fixtures, some imported items

Health Effects:

Developmental issues in children, kidney problems, high blood pressure

Regulatory Limit:

EPA Action Level: 15 ppb (0.015 mg/L)

Treatment Options:

NSF-certified filters, replace lead pipes and fixtures
Arsenic

Sources:

Natural deposits, industrial waste, pesticide runoff

Health Effects:

Cancer, skin damage, circulatory system problems

Regulatory Limit:

EPA Maximum Contaminant Level: 10 ppb (0.010 mg/L)

Treatment Options:

Reverse osmosis, distillation, special arsenic filters
Mercury

Sources:

Industrial waste, fossil fuel combustion, natural deposits

Health Effects:

Kidney damage, neurological disorders

Regulatory Limit:

EPA Maximum Contaminant Level: 2 ppb (0.002 mg/L)

Treatment Options:

Activated carbon filters, reverse osmosis

Understanding Water Quality Reports

Water utilities are required to provide annual Consumer Confidence Reports (CCRs) that list contaminants detected in your water. Here's how to interpret them:

  • MCL (Maximum Contaminant Level): The highest level of a contaminant allowed in drinking water.
  • MCLG (Maximum Contaminant Level Goal): The level below which there is no known or expected health risk.
  • ppm (parts per million): Equivalent to milligrams per liter (mg/L).
  • ppb (parts per billion): Equivalent to micrograms per liter (μg/L).
  • ppt (parts per trillion): Used for extremely low concentrations of contaminants.