Sulfate (SO4) can be found in almost all natural water. The origin of most sulfate compounds is the oxidation of sulfite ores, the presence of shale, or of industrial wastes. Sulfates can also be due to a combination of sulfur and oxygen and are a part of naturally occurring minerals in some soil and rock formations that contain groundwater. The mineral dissolves over time and is released into groundwater.

Sulfate is also one of the major dissolved components of rain.

Sulfate minerals can cause scale buildup in water pipes similar to other minerals and may be associated with a bitter taste in water that can have a laxative effect on humans and young livestock. Elevated sulfate levels in combination with chlorine bleach can make cleaning clothes difficult

According to the EPA Web site of Drinking Water Contaminants, Sulfate is a substance that occurs naturally in drinking water. 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. Of particular concern are groups within the general population that may be at greater risk from the laxative effects of sulfate when they experience an abrupt change from drinking water with low sulfate concentrations to drinking water with high sulfate concentrations.