Sulfate
Sulfate is a naturally-occurring substance. Health concerns regarding sulfate in drinking water have been raised because of reports that diarrhea may be associated with the ingestion of water containing high levels of sulfate.

Sulfate in drinking water currently has a secondary maximum contaminant level of 500 milligrams per liter, based on aesthetic effects (i.e., taste and odor). This regulation is not a federally-enforceable standard, but is provided as a guideline for states and public water systems. The Las Vegas Valley's water supply falls within this secondary maximum contaminant level.

For more information, go to the Environmental Protection Agency's sulfate in drinking water page.