Bottled water is drinking water sealed into containers for consumer sale and is one of the most widely consumed beverages globally. It can originate from various sources, including protected underground formations or municipal water systems. The journey from source to bottle involves distinct classification criteria and rigorous industrial processes designed to ensure purity and consistency. Understanding these steps clarifies the differences between the many products available and the regulatory framework that governs their quality.
Understanding the Types of Bottled Water
The classification of bottled water depends heavily on its source and the degree of treatment it undergoes before packaging. Federal regulators establish “Standards of Identity” that define what terms like “spring” or “mineral” water legally mean on a label. This framework helps consumers understand the product’s origin and inherent characteristics.
Spring Water
Spring Water is derived from an underground formation where water naturally flows to the surface. It must be collected either at the natural opening or through a borehole that taps the exact underground source feeding the spring. Regulations stipulate that this water must maintain the same composition and quality as the water that naturally surfaces.
Mineral Water
Mineral Water is defined by its Total Dissolved Solids (TDS) content, which must be at least 250 parts per million (ppm) at the source. This water originates from a geologically protected underground source and must have a constant level and relative proportion of minerals and trace elements. No minerals can be added, ensuring its unique composition is entirely natural.
Artesian Water
Artesian Water comes from a well that taps a confined aquifer, a water-bearing layer trapped between two impermeable layers. The water is under sufficient natural pressure, known as artesian pressure, to rise above the top of the aquifer without a mechanical pump. This pressure often forces the water to the surface, allowing for collection.
Purified Water
Purified Water contrasts with naturally sourced waters because it can come from any source, including municipal tap water. It is defined by the extensive treatment it receives, such as distillation, deionization, or reverse osmosis, to achieve a high level of purity. The final product must contain no more than 10 parts per million of total dissolved solids, making it essentially free of chemicals.
Sourcing and Purification Processes
The manufacturing process for bottled water is a highly controlled sequence of steps, varying based on the source (protected spring or municipal supply). Source water first undergoes extensive pre-treatment to prepare it for advanced purification. This initial phase typically involves mechanical filtration to remove large particulate matter, dirt, and sediment.
Activated carbon filters are a significant component of pre-treatment, particularly when starting with municipal water. These filters use adsorption to remove chlorine, organic compounds, and elements that can affect taste and odor. Removing chlorine at this stage protects the delicate semi-permeable membranes used in subsequent purification steps from chemical damage.
For purified water, the main treatment often involves Reverse Osmosis (RO). High pressure is applied to force water through a membrane with microscopic pores, rejecting up to 99% of dissolved inorganic solids, including salts and heavy metals. Distillation is an alternative method, involving boiling the water and condensing the steam to leave contaminants behind.
After purification, the water must be disinfected to remove any remaining microbes before bottling. The industry predominantly uses ozonation, which involves exposing the water to ozone gas (O₃), a powerful oxidizer. Ozone is preferred over chlorine because it is highly effective at killing bacteria and viruses, yet it rapidly decomposes back into oxygen, leaving no residual chemical taste or odor. The final stage is an automated, sanitary process where the water is filled into pre-sterilized bottles and sealed immediately to prevent post-treatment contamination.
Regulatory Oversight and Quality Standards
In the United States, bottled water is regulated as a packaged food product by the Food and Drug Administration (FDA). This is distinct from municipal tap water, which falls under the jurisdiction of the Environmental Protection Agency (EPA). By federal mandate, the FDA’s regulations for bottled water must be at least as stringent as the EPA’s standards for public drinking water.
The FDA enforces strict quality standards and mandates contaminant limits for chemical, physical, microbial, and radiological substances. For instance, the maximum allowable level for lead in bottled water is set at 5 parts per billion, compared to the 15 parts per billion limit set by the EPA for tap water. Bottlers must also follow Current Good Manufacturing Practices (CGMPs), which govern facility design, sanitary maintenance, and quality control testing.
These regulations ensure that the claims made on the bottle’s label meet the legally defined Standards of Identity. If a product uses a public water source and does not meet the FDA’s definition of “purified” or “sterile” water, the label must clearly state that the water is sourced from a community water system. This oversight maintains product safety and provides consumers with accurate information.