Journal

Spring water vs mineral water vs purified water: what is the difference?

The three names on the front of a water bottle are not interchangeable. In the United States each one is a defined term under the FDA's standard of identity for bottled water, and each answers a different question. Spring water is about where the water surfaces. Mineral water is about what it carries. Purified water is about what has been done to it. Once you know which question a label is answering, the rest of the bottle becomes much easier to read.

The short version

Spring water comes from an underground formation that flows naturally to the surface, and is collected at the spring or through a borehole tapping the same source.
Mineral water comes from a protected underground source and contains at least 250 mg/L of total dissolved solids, with no minerals added.
Purified water has been treated by distillation, deionization, reverse osmosis or a similar process, which strips out nearly all dissolved minerals.

The categories can overlap. A spring water with enough natural mineral content may also meet the mineral water standard. A purified water can start out as municipal or well water. None of the three terms says anything about price or quality on its own.

Spring water: defined by the source

The FDA definition of spring water is geological. The water must come from an underground formation that rises to the surface on its own, and it must be collected at that spring or through a bore that draws from the same formation, with the same composition as the water at the spring. The definition sets no minimum or maximum for minerals, so spring waters vary widely.

Some of the lightest waters we carry are spring waters: Saratoga from Saratoga Springs, New York, at 116 mg/L; Acqua Panna from Tuscany at 130 mg/L; Mountain Valley from Hot Springs, Arkansas, at 220 mg/L. Others, such as Evian from the French Alps at 357 mg/L and Hildon from Hampshire at 312 mg/L, are spring sources that carry enough dissolved minerals to clear the 250 mg/L line.

Mineral water: defined by the content

Mineral water is the only one of the three terms with a number attached. To use the name in the US, a water needs at least 250 mg/L of dissolved solids, drawn from a source that is geologically and physically protected, and its minerals must be naturally present rather than added afterward. Below 500 mg/L a label may add "low mineral content"; above 1,500 mg/L, "high mineral content".

Within that one word sits an enormous range. San Benedetto from the Veneto just clears the threshold at 254 mg/L. Perrier sits at 475 mg/L, S.Pellegrino at 970, and Vichy Catalan at 3,052, a water so mineral it tastes distinctly salty. If the numbers are new to you, our explainer on what TDS in water means walks through them.

Purified water: defined by the process

Purified water starts with any approved source, including municipal supply, and is then treated until almost nothing remains dissolved in it. The FDA allows the label to name the method, so you will see "distilled water" or "reverse osmosis water" as well as "purified". The result tastes very clean and very neutral, because the minerals that give spring and mineral waters their character have been removed.

Many purified brands add a small, measured amount of minerals or electrolytes back for taste, and list them on the label. In our range, Essentia, Alkaline88, Boxed Water, Path Water and Open Water are purified waters, with published TDS between about 25 and 60 mg/L. They are not spring or mineral waters, whatever the bottle's design suggests, and the distinction is about origin rather than merit.

Artesian water, the label in between

Artesian water is a fourth FDA category worth knowing. It comes from a well that taps a confined aquifer, a layer of rock or sand under pressure, where the water level rises above the top of the aquifer. Voss from Norway, Fiji, and Vellamo from Finland are artesian waters in our range. Like spring water, the term describes the source, not the mineral content.

Why European labels read differently

Bottles from Europe often say "natural mineral water", an EU category with its own rules. The source must be underground, protected and officially recognized, the water must be bottled at the source, and its composition must stay stable over time. Treatment is tightly limited: unstable elements such as iron can be separated, and carbon dioxide can be removed or added, but the water cannot be disinfected or have minerals added.

The EU rules set no minimum TDS. That is why Tŷ Nant from Wales can be sold as a natural mineral water at 165 mg/L, below the American 250 mg/L threshold. Neither label is wrong. They are answering different regulatory questions.

Which should you choose?

Choose by taste and use, not by the category name. If you want something light for everyday drinking, a low-mineral spring water is an easy place to start; browse our still waters. If you want body and a firm finish with food, look at mineral waters above 500 mg/L, most of them in our sparkling range. If you want the most neutral possible base, purified water is built for exactly that.

Frequently asked questions

Can a water be both spring water and mineral water?

Yes. A spring water that comes from a protected source and naturally carries at least 250 mg/L of dissolved solids meets both definitions. The producer decides which name to put on the label.

Is purified water the same as distilled water?

Distillation is one of several methods that produce purified water. Reverse osmosis and deionization are others. A label may name the specific method used.

Why is a European "mineral water" sometimes below 250 mg/L?

EU natural mineral water is defined by a recognized, protected source and a stable composition, not by a minimum mineral content. The 250 mg/L threshold is an American rule.