Types of Water Explained: Spring, Artesian, Mineral, Purified, and Distilled

What Are the Different Types of Water?

Walk down the water aisle and you'll see spring, artesian, mineral, purified, distilled, alkaline, and a few names in between. It looks like marketing. Most of it isn't. The bottled labels are legal terms, and the U.S. Food and Drug Administration defines each one in its standards of identity (21 CFR 165.110).

The common types you'll run into are tap, well, spring, artesian, mineral, purified, distilled, deionized, reverse osmosis, filtered, alkaline, and sparkling. There are two useful ways to sort them, and once you have those, every label starts to make sense.

The first is by source: where the water comes from before anyone touches it. Tap, well, spring, artesian, and mineral water are all source categories. The second is by treatment: what's been done to it. Purified, distilled, deionized, reverse osmosis, and filtered water are all treatment categories.

Here's the part most articles skip. The word on the bottle tells you less about the water than what's actually dissolved in it. After decades of building filtration systems at Crystal Quest®, that's the lens we use: not "what's it called," but "what's in it, and is that what you want to drink." This guide walks through every common type on both axes, then answers the question you actually came for, which is which one to drink.

Key Takeaways

Types of Water at a Glance

Here's every common type on one screen, with what it is and where it usually shows up. The sections below go deeper on each one.

Water Types by Source

Source is where the water starts. It shapes the mineral content and, often, the taste, long before any filter or treatment enters the picture.

Tap Water

Tap water is what comes out of your faucet from a municipal supply. In the United States, water from public systems is regulated by the Environmental Protection Agency, which sets legally enforceable limits on contaminants for public water systems. That's a real floor of safety, and it's why the tap is a reasonable starting point for most homes.

It's a floor, though, not a ceiling. Tap water still carries whatever survives treatment and whatever it picks up on the way to you: chlorine or chloramine used to disinfect it, hardness minerals from the ground, and sometimes lead from older household plumbing. Quality genuinely varies from one town to the next, which is why two people can have very different opinions about "tap water" and both be right.

Well Water

Well water comes from a private well drawing on groundwater, and here's the catch that surprises people: private wells aren't covered by EPA drinking water rules. Testing and treatment are the owner's responsibility. Well water is often rich in minerals and can be excellent, but it can also carry bacteria, nitrates, iron, or hardness that city water would have handled. If you're on a well, the smart move is to test, then treat for what you find. We cover the split in well water vs city water.

Spring Water

Spring water has a specific FDA meaning. It has to come from an underground formation from which water flows naturally to the surface, and it has to be collected either at the spring or through a bore hole tapping that same underground formation. It usually keeps the minerals it picked up underground, which is where its taste comes from. "Spring water" isn't a promise that the water is purer, only that it came from a spring.

Artesian Water

Artesian water is spring water's pressurized cousin. It comes from a well that taps a confined aquifer, an underground layer of rock or sand where the water sits under enough natural pressure that its level rises above the top of the aquifer. That pressure is the whole story. It's why artesian water carries a premium image, though in practice it's groundwater like any other, defined by its source rather than by being cleaner.

Mineral Water

Mineral water is the one type with a number attached. The FDA defines it as water containing at least 250 milligrams per liter of total dissolved solids, coming from a protected underground source. Two rules matter here: the minerals have to be naturally present at a constant level, and no minerals may be added. So mineral water isn't manufactured, it's found. The dissolved calcium, magnesium, and other elements give it a distinct taste, which is the point for most people who buy it.

Water Types by Treatment

Treatment is the other axis. These categories describe what was done to the water, usually to pull out dissolved solids and contaminants, not where it came from.

Purified Water

Purified is the umbrella term, and it trips a lot of people up. Under the FDA standard, purified water is water that's been produced by distillation, deionization, reverse osmosis, or other suitable processes and meets a low dissolved-solids purity standard. In other words, distilled, deionized, and reverse osmosis water are all types of purified water. If a bottle says "purified," it was cleaned by one of those methods. We break the label down in filtered water vs purified water and cover the mineral question in does purified water have minerals.

Distilled Water

Distillation is the oldest trick in the book. You boil water into steam, then cool the steam back into liquid in a separate chamber. The minerals, metals, and most other dissolved solids stay behind in the boiling vessel because they don't evaporate with the water. What you collect is close to zero dissolved solids, which is why distilled water tastes flat and why it's a favorite for steam irons, CPAP machines, and lab work where minerals would cause scale or interference. Whether it's a good everyday drink is a separate question we answer in can you drink distilled water, and we compare it head to head in distilled water vs reverse osmosis.

Deionized Water

Deionized water, often shortened to DI water, is made by running water through ion-exchange resins that pull out dissolved charged particles, the ions. The result is extremely low in dissolved minerals, which makes it valuable in laboratories, electronics manufacturing, and cooling systems where even trace minerals cause problems. Deionization doesn't necessarily remove bacteria or non-ionic contaminants, so DI water is a purity tool for industry more than a drinking choice. If you're weighing the two, distilled vs deionized water and can you drink deionized water lay it out.

Reverse Osmosis Water

Reverse osmosis, or RO, is the method most people can actually run at home. It pushes water through a semipermeable membrane with pores so fine that water molecules pass but the large majority of dissolved solids, metals, and many contaminants don't. It's the practical way to make purified water at your own sink, and unlike distillation it doesn't need heat. Because RO strips minerals along with the bad stuff, many systems add a remineralization stage to put a little taste and mineral content back, which we explain in how to remineralize reverse osmosis water.

Filtered Water

"Filtered water" is the loosest term of the bunch, and it's worth separating from "purified." Filtration usually means passing water through carbon or sediment media to improve taste and cut specific contaminants like chlorine, some organics, or particles. It isn't the same as purification. A carbon filter makes water taste better and removes real contaminants, but it doesn't strip dissolved solids the way distillation or RO does. Both are useful. They just do different jobs.

Alkaline Water

Alkaline water simply has a pH above neutral, meaning it's less acidic than plain water. That higher pH can come naturally, when water picks up minerals underground, or it can be produced by an ionizer that separates the water electrically. The mineral route raises pH by adding something, while an ionizer rearranges what's already there. It's largely a taste preference, and it's a category people ask about far more than the science supports.

Sparkling Water

Sparkling water is water with carbon dioxide dissolved into it, whether it bubbled up that way from a spring or the fizz was added later. The FDA recognizes "sparkling bottled water" as its own label. The carbonation doesn't change what's dissolved in the water in any meaningful way for filtration purposes. It's a beverage choice, not a purity one.

Which Type of Water Is Best to Drink?

Strip out the marketing and the answer gets simple. For most households, the best water to drink isn't a specific bottled label at all. It's clean water from your own tap, filtered to remove what you don't want.

Think about what each bottled type is really selling. Spring and mineral water sell a source and a taste. Purified, distilled, and RO water sell the absence of dissolved solids. You can get either at home. A good filter or reverse osmosis system lets you decide what stays and what goes, at a fraction of the cost of bottled water and without the plastic waste. The label stops mattering once you control the water yourself.

One more "type" is worth naming, because people feel it every day: hard water versus soft water. That's about dissolved calcium and magnesium. The U.S. Geological Survey classifies water hardness as soft below 60 mg/L as calcium carbonate, moderately hard from 61 to 120, hard from 121 to 180, and very hard above that. Hard water is safe to drink, but it scales your pipes and appliances, which is why so many homes soften or condition it. We go deeper in the complete hard water guide.

The practical path is short. Find out what's in your water, decide what you want gone, and match a system to it. If you're not sure where to start, that's exactly the kind of thing our water specialists sort out every day.

Frequently Asked Questions About Types of Water

What is the healthiest type of water to drink?

For most people it's clean, properly filtered water from a safe source, not any single bottled label. What matters is that harmful contaminants are removed and the water isn't stripped of everything. Filtered tap water, or reverse osmosis water with a little mineral content added back, covers both.

What is the difference between spring water and purified water?

Spring water is defined by its source. It flows naturally to the surface and keeps its natural minerals. Purified water is defined by treatment. It's been distilled, deionized, or run through reverse osmosis to remove dissolved solids. One tells you where the water came from, the other tells you what was done to it.

Is mineral water better than regular water?

Mineral water contains at least 250 mg/L of dissolved solids by FDA definition, so it does deliver some minerals and a distinct taste. It isn't a meaningful way to meet your daily mineral needs, though, since food provides far more. For most people it's a taste preference rather than a health upgrade.

Is distilled water the same as purified water?

Distilled water is one kind of purified water. The FDA lists distillation as one of the accepted purification methods, alongside deionization and reverse osmosis. So all distilled water is purified, but not all purified water is distilled. It could have been made by RO or deionization instead.

What type of water is best for humidifiers, CPAP machines, and irons?

Low-mineral water is best for appliances, which usually means distilled or reverse osmosis water. Regular tap water leaves mineral scale behind as it evaporates, and that buildup shortens the life of the device. Distilled water is the common recommendation because it's close to zero dissolved solids.

Can I make purified water at home?

Yes. Reverse osmosis is the practical home method. An RO system pushes water through a fine membrane and produces low-solids purified water right at your sink, with no heat or boiling required. Many systems add a remineralization stage so the water tastes better than plain RO or distilled.