Culligan does sell purified water, and it’s one of their core products. Their “Pure Drinking Water” line goes through a multi-stage reverse osmosis process that meets the FDA’s definition of purified water. However, Culligan also sells spring water and distilled water, so not every bottle or jug with a Culligan label has been purified the same way. The distinction matters depending on what you’re looking for.
How Culligan Purifies Its Drinking Water
Culligan’s purified water goes through five stages of filtration before it reaches your glass. The process starts when water enters the facility and passes through two parallel carbon filters, which strip out chlorine and dissolved solids. From there, the water moves through a softening step that removes hard-water minerals like calcium and magnesium, along with trace metals such as aluminum and copper. A secondary polishing softener catches any remaining residue.
The main event is reverse osmosis. Water is forced through a semipermeable membrane that works like an extremely fine net, catching contaminants down to the size of a micron. This includes things like lead, copper, bacteria, viruses, nitrate, microplastics, and PFAS (the “forever chemicals” that have become a growing concern in municipal water). The RO process drops total dissolved solids from around 1,000 parts per million to under 10 ppm, which represents a reduction of about 99%.
In the final step, the water passes through ozone treatment and ultraviolet light to kill any remaining microorganisms. By the end, Culligan’s purified water is essentially stripped down to its most basic molecular form.
Purified, Spring, and Distilled: Three Different Products
Culligan offers three distinct types of bottled water, and each one is treated differently.
- Pure Drinking Water (purified): This is the reverse osmosis product described above. It’s available in sizes ranging from 20-ounce bottles up to 5-gallon jugs. Nearly all minerals and contaminants have been removed.
- Spring Water: Available in 1-gallon to 5-gallon sizes. The FDA requires spring water to come from an underground source, and it’s filtered more gently to preserve naturally occurring minerals. It tastes different from purified water because those minerals remain.
- Distilled Water: Sold in 1-gallon containers. Distillation involves boiling water and collecting the steam, which leaves contaminants behind. This is the type often used for medical devices, humidifiers, and steam irons.
All three meet FDA standards for their respective categories, but if you specifically want purified water, look for the “Pure Drinking Water” label.
Water Softening Is Not the Same as Purification
This is where things get confusing for many Culligan customers, because the company is probably best known for its water softeners. A water softener and a purification system do very different things.
Water softeners use a process called ion exchange. Your water flows through a tank filled with tiny resin beads that carry a negative charge. Calcium and magnesium ions, which are positively charged, get attracted to the beads and pulled out of the water. The softener then periodically rinses those minerals off the beads using a salt solution so the system can keep working. The result is water that won’t leave scale buildup on your fixtures and appliances, but it still contains other dissolved substances. Softened water is not purified water.
Reverse osmosis goes much further. It removes chlorine, lead, bacteria, viruses, microplastics, and dissolved solids that a softener can’t touch. If you have a Culligan water softener installed in your home, your water is softer but not purified. To get purified water at the tap, you’d need a Culligan RO system, which the company sells as a separate under-sink or whole-home unit.
What “Purified” Actually Means by FDA Standards
The FDA requires water labeled “purified” to have been treated through one of three methods: reverse osmosis, deionization, or distillation. All three processes remove essentially everything except the water molecules themselves. Culligan uses reverse osmosis for its purified bottled water line, which eliminates around 97% of total dissolved solids.
Spring water, by contrast, only needs to come from a protected underground source and pass through basic filtration. It’s clean and safe, but it’s not purified in the regulatory sense. If you’re buying Culligan water specifically because you want the lowest possible mineral and contaminant levels, the purified option is the one to choose. If you prefer some mineral content for taste, spring water is the better fit.