California Water Quality Directory

Find detailed information about water quality in cities and ZIP codes across California. Discover which contaminants might be present and understand how they compare to EPA and recommended limits.

About Water Quality

Water quality is a measure of the suitability of water for a particular use based on selected physical, chemical, and biological characteristics. In California, water quality can vary significantly by location, affected by factors such as:

Understanding Contaminants

Water contaminants include a wide range of substances from natural minerals to industrial chemicals. Some have health implications, while others affect taste, odor, or appearance of water.

EPA Standards

The Environmental Protection Agency (EPA) sets legal limits for contaminants in drinking water. These standards protect public health by limiting the levels of contaminants allowed.

Health Guidelines

Beyond EPA limits, there are often stricter health-based guidelines recommended by scientists and health organizations for optimal water quality.

Common Contaminants

Common water contaminants in California include arsenic, lead, nitrates, bacteria, pesticides, and industrial chemicals that can vary by region.