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Private Wells and Sulfate

Sulfate usually occurs naturally in the groundwater in New Mexico because the water dissolves it out of rocks, such as gypsum. Natural levels can be increased by contamination from mines, mills, landfills, sewage and other manmade sources.

Drinking water with sulfate concentrations above 250 milligrams per liter (mg/L) may have undesirable taste and odor. To avoid loose stool and diarrhea in persons not used to high levels of sulfate, the EPA advises public water systems and private wells not have sulfate above 500 mg/L. Drinking water with sulfate levels above 600 mg/L can cause strong laxative effects. Diarrhea and resulting dehydration may be more pronounced (and serious) for certain groups of people such as babies and people not used to higher sulfate water (visitors).
Levels of various naturally-occurring and man-made constituents in New Mexico groundwater including sulfate, might be elevated above the Environmental Protection Agency (EPA) Safe Drinking Water secondary standards (related to odor and taste). Ongoing drought conditions and aquifer mining have raised further concern that increases in constituents may occur in the absence of significant ground water recharge events. To assure that the water is safe for human consumption, well owners should periodically test their wells.

The information available on this page, including the maps, demonstrates sulfate found in tested private wells in New Mexico based on the data available from various sources.

To know the sulfate concentration in your water from your own well, you need to test. Learn about testing.

Wells Sampled 1903-2018

Sulfate levels in water samples from private wells vary between New Mexico counties and even within the same county. The groundwater system in New Mexico is very complex. This complexity can lead to sulfate concentration variability even amongst neighboring wells. Therefore, to know the sulfate concentration in your water from your own well, you need to test.

The secondary safe drinking water concentration for sulfate, related to aesthetics (odor and taste), is 250 milligrams per liter (mg/L). Some of the water samples from wells in all counties appear to exceed this Environmental Protection Agency (EPA) Safe Drinking Water secondary standard. However, counties with at least 45 percent of samples that exceed this standard are in south eastern NM.

People who drink water containing sulfate in excess of EPA's could experience a laxative effect.

Learn more about Sulfate and Health. Sulfate Distribution in NM private wells 1903-2018

Sulfate Distribution in New Mexico Private Wells (Wells Sampled Aug 1903 - Oct 2018
Sulfate Distribution in New Mexico Private Wells (Wells Sampled Aug 1903 - Oct 2018
New Mexico Private Wells Inventory (Sulfate Test Results Summary Aug 1903 - Oct 2018
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Content updated: Fri, 5 Apr 2019 15:14:30 MDT