Types and categories of drinking water

Nurbol Zhaksybek

warehouse operator

Published: 17 September 2026 Updated: 25 September 2026

The type of water is set by its source, composition and treatment

The word “drinking” on a bottle is not a description but a permit: it only means the water is allowed to be drunk. Everything else is hidden in the small print under the composition, and that is where it says how one bottle differs from the one next to it that costs twice as much. The difference between them is almost never the brand and almost always three lines: source, mineralisation, treatment method.

Three questions instead of a name

Water classification is simpler than the shop shelf suggests: it answers three questions in a row — where the water was taken from, what is dissolved in it and what was done to it before bottling. All the familiar names, from table water to distilled, come from a combination of these three answers, and none of them appears on its own.

Where from, what is inside and what was done

The first question is about the source. Water comes either from underground, from an aquifer, or from the surface: from a river, lake or reservoir, or from a melting glacier. Underground water is covered by a layer of dense rock and changes slowly, over years; surface water depends on the weather, floods, spring runoff and everything that has entered the catchment further upstream.

The second question is about composition. Dissolved calcium, magnesium and sodium salts and bicarbonates give water its taste and determine whether it is fit for everyday drinking or only for a course prescribed by a doctor. They are measured as total mineralisation, also called total dissolved solids, in milligrams per litre. This is the first figure worth looking for on the label, and often the only one there that really means anything.

The third question is about treatment. One water is only disinfected and bottled, another is pushed through a membrane and has its mineral composition rebuilt, a third is evaporated until no salts are left at all. This determines what will be left in the glass besides the water itself, and why two bottles with the same words on the side can taste completely different.

Four features in one line each

• Origin — underground from a protected aquifer, spring, glacier, surface, tap
• Composition — by mineralisation: table, medicinal table, medicinal
• Treatment — natural, purified, distilled
• Bottled water category — first or premium

Below we go through each line separately and finish with what people usually open articles like this for: which water makes sense to keep at home all the time, which to take as a short course, and which not to drink at all. None of the types is universal, and that is perhaps the main conclusion of the whole classification.

Types of drinking water: how they are really classified

Classification by source is the most honest of all, because it cannot be rewritten after the fact. A source either exists or it does not; it is stated in the documents together with the well number or the name of the water intake, and any reputable supplier can show it to you. Composition can be improved by treatment and the wording on the label can be softened, but origin is the hardest thing to fake.

Upper and lower aquifers

Underground water has its own ladder too, and the gap between its rungs is bigger than between some brands. Upper aquifers lie shallow, have nothing covering them and are fed by rain and melting snow, together with everything those picked up along the way. Lower ones are separated from the surface by an impermeable cap and live a life of their own, hardly noticing what happens above.

Surface water after treatment

Surface water is bottled too, but only after full water treatment: clarification, filtration, disinfection and reverse osmosis. After that chain almost nothing of the original river is left, and in composition the result is closer to purified tap water than to natural water. This is legal and safe; it is just not accurate to call such water natural.

The source line on the bottle

So the first thing to look for on a bottle is not a grand name but the line about the source. If it says “from the municipal water supply”, you are looking at purified tap water, and the price should match. If it gives the aquifer, the depth and the well number, the supplier has something to show, and the conversation moves on to composition.

Artesian water: what the word on the label means

Artesian water is water from a confined aquifer, that is, from a layer squeezed between two impermeable layers of clay or dense rock. The pressure in such a layer is higher than atmospheric, so once a well opens it, the water rises up the borehole by itself and sometimes flows out onto the surface without a pump. The name comes from the French province of Artois, where wells like this were drilled as early as the Middle Ages.

The cap above the aquifer

What matters most here is not the depth as such but the cap above the aquifer. It is what cuts off surface runoff: rain, melting snow, runoff from fields and everything that seeps down from above. Water under the cap receives no new load of contaminants and lives by its own rules — slowly filtering through the rock and picking up salts from it.

Age and stable composition

Hence the second feature — age. Between entering the aquifer and being pumped up, tens or even hundreds of years pass. In that time the water passes through sand, gravel and limestone, loses suspended matter and organic material, and gains a stable mineral composition. Stable is the key word: at the same well, the readings vary from year to year within about ten per cent, not by several times.

• A closed aquifer — surface runoff does not get into the layer
• A constant composition — season and weather hardly affect mineralisation
• Little organic matter — so there is no need for harsh disinfection
• Mineralisation already in place — the salts come from the rock, not added on the line

The mineralisation of such waters usually falls within a range of two hundred to six hundred milligrams per litre and depends on which rocks the aquifer has passed through. Limestone adds calcium and bicarbonates, dolomite adds magnesium, and sandstones give soft water with low total dissolved solids. That is why two wells in the same region can give water with a noticeably different character.

How it differs from water from a shallow well

A well at a country house twenty or thirty metres deep usually taps groundwater — the unconfined aquifer with no cap. It is fed from above, and along with the rain it receives nitrates from vegetable gardens, traces of fuel from roads and bacteria. Such water can be clear and pleasant-tasting, but its composition changes after every heavy rain, and it needs testing not once a year but every season.

The difference shows up in the documents straight away: the passport of a confined-aquifer well states the aquifer and the impermeable cap, and on the delivery note the water is recorded exactly that way — artesian water, with the well number; the passport of a domestic well gives only the depth. If a supplier talks about a well but does not name the aquifer, it is almost certainly shallow water, and the price of the bottle should reflect that.

Spring, glacier and tap water: three neighbouring cases

The spring and its open outlet

Spring water is the same underground aquifer, only it has reached the surface on its own, without a well. Its composition can be excellent, but it has a weak point: the outlet is open. After a downpour or a flood, surface water gets into the spring intake, and the readings drift for several days. A conscientious bottler takes this into account and stops the line; an unscrupulous one does not.

Glaciers and meltwater

Glacier water and meltwater sit at the other end of the scale. Unlike artesian water, they contain almost no salts: total dissolved solids are often below fifty milligrams per litre. It is pleasant to drink and feels light, but water like this does not work as a regular source of minerals — the body then gets calcium and magnesium only from food.

Tap water and boiling

Tap water in a large city is usually mixed: part of it comes from surface intakes, part from underground ones, and the share of each changes with the season. It goes through full treatment and is safe by the standards, but it has two properties that cannot be removed — residual chlorine and a variable composition. On top of that there is the condition of the pipes between the plant and the flat, and no test report at the plant outlet shows that.

Boiling removes bacteria and some of the hardness, but it does not remove nitrates or heavy metals, and it even raises the salt concentration slightly through evaporation. So boiled tap water is disinfected tap water, not a separate, cleaner type of water.

Mineral water: where the line with drinking water runs

Mineral water is water from an underground source with a higher content of salts and trace elements, whose composition is stable and confirmed by testing. What sets it apart from ordinary drinking water is not its origin — that is the same — but how much is dissolved in it: rocks at depth can be richer, and total dissolved solids go above a gram per litre.

Table, medicinal table, medicinal

The line between drinking and mineral water runs along mineralisation, and it is a formal one. Up to one gram per litre the water counts as table water and can be drunk without limits. From one to ten grams it is medicinal table water: it is taken as a course, usually no more than a glass or two a day. Above ten grams it is medicinal water, and that is no longer a drink but a remedy that is prescribed.

When the aquifer gives up a lot of salts

The words “artesian mineral water” are not a contradiction and not a trick: such water is raised from the same confined aquifer, it is just that the layer gave it more salts along the way. In this case look not at the word about the well but at the total dissolved solids figure — that is what decides whether it is everyday water or water for a course.

Two extremes

The mistake people make most often is taking a bottle of medicinal table water as their everyday water because it is “healthier”. The body does not need that amount of salts every day: excess sodium retains fluid, excess sulphates upset digestion. The benefit is not linear here, and more does not mean better.

The opposite extreme happens too: someone drinks water with total dissolved solids of fifty milligrams for years and wonders why they get calf cramps. The body takes calcium and magnesium from everywhere, and drinking water makes up a noticeable share of that balance. A sensible range for everyday water lies roughly between two and five hundred milligrams per litre.

Read more: Mineral water delivery

Purified and distilled: what a membrane does to water

Purified water is tap or surface water that has gone through industrial treatment: mechanical filtration, carbon sorption, reverse osmosis and disinfection. A reverse osmosis membrane lets water molecules through and holds back almost everything else, including hardness salts, nitrates and residual chlorine. What comes out is water close to distilled.

What the membrane takes away along with impurities

Here lies the main side effect: the membrane does not tell the useful from the useless. Along with nitrates and chlorine it removes calcium, magnesium and bicarbonates — everything that makes water worth drinking rather than just swallowing. That is why a decent plant has a remineraliser after the osmosis stage to put some of the salts back, and the result depends on how it is set up.

• The membrane removes hardness salts, nitrates, chlorine, heavy metals and bacteria
• Calcium, magnesium and bicarbonates go along with them
• The remineraliser puts some salts back — but in the composition the producer has chosen
• Without a remineraliser you get technically pure but flat water

The difference between water with a remineraliser and without one is noticeable from the first sip: the taste of water rests on calcium, magnesium and bicarbonates, and when they have not been put back, what is left in the glass is a chemically flawless but empty liquid. You do not feel like drinking it, and without noticing you switch to tea and sugary drinks — so water bought for the sake of health ends up working against it.

Distilled water: no salts at all

Distilled water is the extreme case of the same idea. It is made by evaporation and condensation, it contains no salts at all, and its total dissolved solids are close to zero. Laboratories, irons and car batteries need it, but it is not meant for regular drinking: you can drink it, but building your water intake on it for months is not a good idea precisely because it has no minerals.

The jug and the under-sink osmosis unit

A home filter jug is not part of this group at all. It improves water in terms of chlorine and some organic matter and softens it a little — and that is all. The cartridge does not hold back nitrates and stops working before you can see it, so a jug should not be treated as a substitute for deep purification.

A home reverse osmosis system under the sink is an honest option, but a demanding one. The membrane is replaced every two or three years and the pre-filters every six months, and a missed deadline turns purification into its opposite: the same biofilm builds up on a worn-out cartridge as in a cooler tank. Plus the remineraliser, which also needs servicing. If there is no one to keep an eye on this, it is more honest to buy ready-made water with a clear source than to keep a unit at home that nobody remembers to service.

Water categories: first and premium, what the difference is

Technical regulations divide bottled water into two categories — first and premium. These are not marketing words and not a verdict on taste: each comes with its own list of requirements for the source, the composition and the depth of treatment. The category is stated on the label, and unlike epithets such as “crystal clear”, it cannot be written in at will.

First category

The first category is the basic safety level. The source can include the municipal water supply, any approved treatment is allowed, and the limits on residual impurities are stricter than for tap water but less strict than for the premium category.

Premium category

The premium category requires a protected underground source and preservation of the natural composition: the water may be disinfected but not rebuilt from scratch. On top of that it must be physiologically adequate — that is, contain calcium, magnesium, fluoride and iodine in amounts the body actually uses. It is this requirement that screens out empty water after osmosis, even if it is perfectly clean.

Standards, not taste

An important caveat: the category is about standards, not taste. First-category water with a well-balanced mineralisation may be more to your liking than premium water with a high bicarbonate content. The category answers the question “how strictly was it tested”, not “will you like it” — and those are different questions.

How to read the label and not buy tap water

The official name of the product on the bottle sounds dull: “drinking water, packaged in containers”. Everything printed larger and more attractively has nothing to do with classification — it is the brand name. Read where the print is small, and start with three lines: source, category, mineralisation.

Natural and purified on paper

Regulatory documents list the types of drinking water packaged in containers, and each comes with its own obligations: natural water has requirements for the source and for preserving its composition, purified water for the depth of treatment and for residual substances. The producer must assign its product to one of them, and that line shows what is actually inside.

Five lines on the back

• Source — the aquifer, depth and well number, or an honest “municipal water supply”
• Category — first or premium
• Mineralisation — a range in milligrams per litre, not one round number
• Composition — calcium, magnesium, sodium, bicarbonates and sulphates with figures
• Bottling date and shelf life — on the container itself, not on a sticker over it

When there is no composition

There is exactly one warning sign, but it is a reliable one: no composition. If instead of figures there is a word about balance and living structure, it means there is nothing to show. Water from a decent source has its composition printed willingly, because that is its main argument.

What goes into a nineteen-litre bottle

Large bottles hold exactly the same types as small ones, only in different proportions. Most often it is water from an underground aquifer, less often purified tap water, and very rarely spring water, because it is hard to keep a large line steadily supplied from a spring. You cannot tell the type from the look of the bottle: you have to look at the batch passport.

Why large bottles are bought from a supplier

Delivery of artesian water in nineteen-litre bottles has grown into a market of its own for a simple reason: it is easier for the buyer to check the supplier's documents once than to read the label in a shop every time. The check is done once, and the result holds for months — provided the supplier does not quietly change the source.

The bottle itself and how it is washed

The second question with large bottles is the bottle itself. A polycarbonate one lasts for years and withstands washing in a hot solution; a PET one is lighter and cheaper but is designed for fewer cycles. Either way, what decides the matter is not the material but whether the bottles are washed between runs and checked for cracks.

Hence a practical rule for large bottles: look at two things at once — the source and how the bottle is handled. Excellent water in a poorly washed bottle stops being excellent by the end of the week, and no category on the label will fix that.

Which type of water to choose for home, office and children

For adults and children to drink

For everyday drinking by adults and children, premium-category artesian drinking water is the best fit: it has a stable composition, a clear origin and mineralisation within the range the body handles without reservations. For children, low hardness and no excess sodium also matter — and that can be seen in the same composition line.

For the kettle and cooking

For the kettle and cooking, simpler water will do: hardness matters more here than a complete composition, because some of the salts drop out as limescale on boiling anyway. That is why a sensible household setup looks like two waters in the kitchen — one for drinking, the other for the pot and the kettle.

Mineral, distilled and purified

Medicinal table mineral water is kept as a separate product and drunk in courses, not instead of water. At home, distilled water is for the iron and the humidifier. Purified tap water is a workable option if the producer is known and the remineraliser is set up properly, and a poor one if a single word is all that is said about treatment.

A five-step check

1. Find the source on the label: protected underground or municipal water supply
2. Check the category — first or premium
3. Check the mineralisation: for everyday drinking, 200–500 milligrams per litre is sensible
4. Check the composition for calcium and magnesium — they are what make water complete
5. Try it and come back to the first four points a week later: the body does not respond straight away

On a delivery note and in a lab report all this looks dry: source, category, total dissolved solids, date of analysis. Behind those four lines stands exactly what we have covered above — a closed aquifer, a stable composition and minimal intervention on the way to the bottle. In essence, the choice is not between brands but between these characteristics, and they are printed on every bottle.