What is smart water, actually?
Strip the branding and smartwater is a two-step recipe: water is vapour-distilled, which removes everything dissolved in it, and a pinch of electrolytes is added back, calcium chloride, magnesium chloride, and potassium bicarbonate, purely for taste. That is the whole product. No sugar, no vitamins, no caffeine, and no ingredient your tap cannot match.
None of which makes it a scam: distilled-then-remineralised water has a genuinely consistent, soft taste, and taste is a fair reason to buy a drink. The marketing question is whether the word electrolytes buys you better hydration. It does not, and here is the honest comparison with what comes out of a UK tap.
Smartwater is vapour-distilled water with flavour-level electrolytes added back, and most UK tap water already carries more minerals, according to TapWater.uk's comparison. Hydration is identical; taste and price per litre are the only real differences.
The electrolyte claim, measured
The electrolytes in smartwater are dosed for flavour, not function. They amount to a few milligrams of minerals per bottle, a rounding error against what food supplies and well below the sodium levels that make sports drinks work during heavy sweating. Hydration research is unambiguous that for everyday drinking, plain water hydrates exactly as well. If you genuinely need electrolyte replacement, an actual electrolyte product with meaningful sodium is the tool; smartwater is not formulated to be one.
Smartwater vs UK tap water
Here is the part the label leaves out: most UK tap water already contains more calcium and magnesium than smartwater adds back, because much of the country's supply runs over chalk and limestone. Hard-water areas drink water carrying hundreds of milligrams of dissolved minerals per litre. The differences that remain are chlorine (tap water carries a trace disinfectant residual that distillation removes) and consistency (your tap varies by region, the bottle never does). Both are taste matters, and both are solvable at home: a carbon filter removes the chlorine note, and a reverse osmosis system with a remineralisation stage is, chemically, the smartwater recipe running under your sink.
What a litre costs
UK mains water costs a fraction of a penny per litre. Bottled smartwater at typical retail runs several hundred times that before counting the plastic. A filter jug lands at pennies per litre and removes the chlorine taste that sends most people to bottled water in the first place. If the soft distilled taste is specifically what you like, RO with remineralisation gets closest and pays for itself against a bottle habit within months.
What does your tap already deliver?
Enter your postcode to see the measured mineral content and quality of your own supply.
Try your postcode — e.g. SW1A, M1, B1
Frequently asked questions
What is smart water?
Smartwater (styled Glaceau Smartwater, owned by Coca-Cola) is vapour-distilled water with electrolytes added back for taste: typically calcium chloride, magnesium chloride, and potassium bicarbonate. The distillation removes everything, the added salts return a clean mineral taste. There is nothing else in it: no sugar, no caffeine, no vitamins in the standard version.
Is smart water good for you?
It is water, so it hydrates you exactly as water does. The added electrolytes are flavour-level amounts, far below what a sports drink or a normal diet provides, and no independent evidence shows a health benefit over tap or other bottled waters. It is not bad for you either; the honest description is premium-tasting water at a premium price.
Does smart water hydrate better than tap water?
No. Hydration comes from the water itself, and the electrolyte quantities in smartwater are too small to change fluid absorption meaningfully for everyday drinking. For heavy sweating, an actual electrolyte drink with meaningful sodium does the job smartwater's marketing hints at. For sitting at a desk, tap water performs identically.
Is smart water worth the price?
As hydration, no: at typical UK retail it costs several hundred times more per litre than tap water, and UK tap water in most areas already contains more calcium and magnesium than smartwater adds back. As a taste preference it is legitimate: distillation gives a consistent, soft taste some people genuinely prefer. A filter jug or reverse osmosis system with remineralisation reproduces much of that character for pennies a litre.