What is still water? It is plain water with no bubbles, the opposite of sparkling or carbonated water. When a waiter asks “still or sparkling?”, still means ordinary, flat water. Tap water, spring water, purified water and most bottled water are all still water. The word only tells you there is no carbon dioxide in it; it says nothing about where the water came from.
Below is how still water compares with sparkling, the types you see on bottled water labels and what the U.S. Food and Drug Administration says each one must be, and which to choose.
Still water vs sparkling water
| Still water | Sparkling water | |
|---|---|---|
| Bubbles | None | Yes, from carbon dioxide |
| Taste | Neutral, depends on minerals | Slightly tangy, because dissolved CO2 forms a weak acid |
| Hydration | Hydrates | Hydrates about the same |
| Calories | Zero | Zero if unflavored and unsweetened |
| Examples | Tap, spring, purified, still mineral water | Seltzer, club soda, sparkling mineral water |
Some people find still water easier to drink in large amounts because bubbles can make them feel full or bloated. Otherwise the choice is mostly taste. Our guide on whether sparkling water hydrates you covers the hydration question in detail.
What does “still” mean on a bottled water label?
Nothing official. FDA rules define bottled water by its source and treatment, not by the word “still.” What the label is really telling you is the type of water. Under 21 CFR 165.110, FDA defines bottled water as water “sealed in bottles or other containers with no added ingredients,” except optional antimicrobial agents and fluoride.
FDA also draws a line around the fizzy drinks: the bottled water rules do not include ingredients labeled “carbonated water,” “seltzer water,” “soda water,” “sparkling water” or “tonic water.” Those are treated as beverages in their own right, which is why a can of seltzer is not regulated as bottled water.
Types of still water
- Spring water. FDA says it must come “from an underground formation from which water flows naturally to the surface of the earth,” collected at the spring or through a bore hole feeding it. Our comparison of spring water vs purified water explains the practical differences.
- Purified water. Water “produced by distillation, deionization, reverse osmosis, or other suitable processes” that meets the U.S. Pharmacopeia standard. It may also be labeled distilled, deionized or reverse osmosis water.
- Mineral water. Water with “not less than 250 parts per million (ppm) total dissolved solids,” from a protected underground source, and “no minerals may be added.” Mineral water can be still or sparkling. Our list of the best mineral water to drink covers both.
- Artesian and well water. Groundwater from a tapped aquifer or a drilled well, also still unless carbonated.
- Tap water. Regulated by the EPA rather than the FDA, and still by default.
Is sparkling water just still water with bubbles?
Often, yes. Seltzer is usually plain water with carbon dioxide added. Sparkling mineral water can be different: FDA says “sparkling bottled water” is water that, after treatment, “contains the same amount of carbon dioxide from the source that it had at emergence from the source.” In other words, some sparkling mineral waters come out of the ground fizzy. Our guide to whether sparkling water and seltzer are the same sorts out the names.
Is still water healthier than sparkling water?
For most people, they are equally good. Plain sparkling water has no sugar or calories and hydrates you. The one area to watch is teeth: carbonation makes water slightly acidic, and flavored sparkling waters with citric acid are more so. If you sip sparkling water all day, still water between meals is the gentler option. Our article on whether sparkling water is good for you goes through the evidence.
Frequently asked questions
Is still water the same as regular water?
Yes. Still water just means water without bubbles. Regular tap water and most bottled water are still water.
Is still water the same as spring water?
Not necessarily. Spring water describes the source; still describes the lack of bubbles. Spring water is usually still, but still water can also be purified, mineral or tap water.
Is still water purified?
Only if the label says purified, distilled, deionized or reverse osmosis water. Those names have FDA definitions. “Still” alone does not mean purified.
What does still mean in a restaurant?
Flat, non-carbonated water, as opposed to sparkling. It may be tap or bottled; ask if it matters to you.
Does still water hydrate better than sparkling?
No meaningful difference for most people. Both hydrate; choose the one you will drink more of.
Can mineral water be still?
Yes. Mineral water is defined by its minerals (at least 250 ppm total dissolved solids under FDA rules), and it comes in both still and sparkling versions.
Sources
- U.S. Food and Drug Administration, 21 CFR 165.110, Bottled water.
