Artesian water is sourced from a unique geological formation that provides a degree of protection from surface contamination. The safety of this water, however, is not guaranteed simply by its origin; it depends entirely on the specific source’s geology, the presence of natural contaminants, and the rigorous processing and regulatory oversight it undergoes before it reaches the consumer. While the confined nature of the source often contributes to a high standard of purity, the presence of naturally occurring elements can introduce health risks if the water is not properly tested and treated.
Defining the Artesian Source
Artesian water is defined by the specific underground structure from which it is drawn. This water is located in a confined aquifer, which is a layer of porous rock, sand, or gravel saturated with water and situated between two layers of poorly permeable material, such as clay or dense rock, known as aquicludes. These impermeable layers trap the groundwater, creating a natural seal that protects it from surface-level pollutants.
The defining characteristic of an artesian source is the presence of hydrostatic pressure within the confined aquifer. This pressure builds because the recharge area, where rainwater or surface water enters the aquifer, is at a higher elevation than the well location. When a well is drilled into this confined layer, the pressure naturally forces the water to rise above the top of the aquifer, sometimes flowing all the way to the surface without the need for a mechanical pump.
Factors Determining Water Safety
Despite the natural protection offered by the impermeable rock layers, artesian water is not inherently free of all potential hazards. The water’s long contact time with the deep geological formations means it can dissolve and accumulate naturally occurring elements that are unsafe in high concentrations. These natural contaminants, such as arsenic, lead, and radon, are specific risks associated with certain bedrock types in deep aquifers. The inherent quality of the water is directly tied to the specific geochemistry of the source rock.
Beyond chemical factors, the microbial purity of artesian water is not absolute. The confined nature of the source protects against many surface bacteria, but contamination can still be introduced during the extraction and bottling process. Poorly constructed well casings or cracks in the confining layers can also create pathways for surface water and microorganisms to enter the aquifer. The presence of beneficial minerals like calcium and magnesium is common and contributes to the water’s taste, but the total dissolved solids (TDS) level, which measures these minerals, is not a direct marker of safety, only of mineral content.
Safety Assurance and Regulatory Oversight
The final safety of commercial artesian water is guaranteed through a comprehensive regulatory framework, primarily managed by the U.S. Food and Drug Administration (FDA). The FDA treats bottled water as a packaged food product and requires its quality standards to be at least as stringent as the municipal tap water standards set by the Environmental Protection Agency (EPA). The FDA has established a specific “Standard of Identity” for artesian water, ensuring the product must meet the geological definition to be marketed under that name.
This regulatory oversight mandates that bottled artesian water undergo regular testing for physical, chemical, microbial, and radiological contaminants. The FDA’s Standards of Quality set maximum allowable levels for more than 90 substances, ensuring the processed water is safe for public consumption. Bottlers must also follow current good manufacturing practices to prevent contamination during collection and packaging.
The regulations for private artesian wells differ significantly, as they fall under the purview of the well owner rather than the FDA or EPA. Owners of private artesian wells are solely responsible for testing their water for contaminants such as coliform bacteria, nitrates, and heavy metals. Private well owners must proactively arrange for annual laboratory analysis to confirm the water remains safe to drink.