Ozone water treatment is a disinfection and oxidation process that uses ozone gas, O3, to treat water. Ozone is closely related to ordinary oxygen, O2, but contains three oxygen atoms instead of two.
Because ozone is highly reactive, it can inactivate microorganisms and oxidize certain substances in water. This makes it useful in municipal treatment plants, bottled-water operations, food processing, industrial systems, and other controlled water-treatment applications.
Quick answer: Ozone is a powerful water-treatment oxidant and disinfectant. It can be effective against microorganisms and can oxidize compounds such as iron, manganese, and hydrogen sulfide under appropriate conditions. However, ozone is not a universal contaminant-removal method, it leaves little lasting disinfectant residual, and it can form unwanted byproducts such as bromate when bromide is present in the source water.
This guide explains what ozonated water is, how ozone generators work, what ozone treatment can and cannot do, and the main advantages and limitations of ozonation.
What Is Ozone?
Ozone is a molecule made from three oxygen atoms: O3.
Ordinary molecular oxygen contains two oxygen atoms, O2. When energy splits an O2 molecule, individual oxygen atoms can temporarily form. These reactive oxygen atoms can then combine with other O2 molecules to form ozone.
Ozone occurs naturally in the atmosphere and can also be produced deliberately using ozone generators.
It is important to distinguish between ozone's usefulness in controlled treatment systems and ozone gas exposure in occupied spaces.
Ozone gas is a respiratory irritant. Ozone used in treatment equipment must be carefully generated, contained, transferred into water, and managed to prevent exposure to unsafe concentrations of the gas.
What Is Ozonated Water?
Ozonated water is water into which ozone gas has been dissolved.
Once ozone enters the water, it reacts rapidly with microorganisms and various chemical compounds. Ozone itself is unstable and eventually breaks down, primarily back into oxygen.
This high reactivity is both an advantage and a limitation.
It allows ozone to act quickly during treatment, but it also means ozone generally does not provide the long-lasting disinfectant residual that chlorine or chloramine can in a distribution system.
How Does Ozone Water Treatment Work?
A typical ozone water-treatment process involves several steps.
- Ozone generation: An ozone generator converts some oxygen into ozone.
- Gas transfer: The ozone-containing gas is introduced into the water.
- Contact time: Ozone reacts with microorganisms and oxidizable substances.
- Post-treatment: Oxidized particles or reaction products may need to be removed through filtration or another downstream process.
- Off-gas management: Undissolved ozone must be safely handled.
The effectiveness of ozone treatment depends on several variables, including:
- Ozone dose
- Contact time
- Water temperature
- pH
- Organic matter
- Turbidity
- Target contaminant
- Other substances in the source water
How Is Ozone Produced?
Most ozone used for water treatment is generated on-site because it is unstable and difficult to store for long periods.
Two common generation methods are corona discharge and ultraviolet generation.
Corona Discharge Ozone Generators
Corona discharge systems use a high-voltage electrical field to split oxygen molecules.
Some of the resulting oxygen atoms combine with O2 molecules to form O3.
Corona discharge is widely used where higher ozone concentrations are required.
UV Ozone Generators
Certain wavelengths of ultraviolet light can also split oxygen molecules, creating ozone.
UV ozone generators generally produce lower ozone concentrations than many corona-discharge systems and are more common in smaller or specialized applications.
How Is Ozone Added to Water?
Generating ozone is only part of the process. The gas must also be efficiently transferred into the water.
Common approaches include:
- Venturi injectors
- Diffusers
- Contact tanks
- Specialized gas-transfer equipment
The objective is to maximize contact between ozone and water while preventing uncontrolled release of ozone gas.
What Can Ozone Do in Water Treatment?
Ozone can serve both as a disinfectant and as an oxidizing agent.
Microbial Disinfection
Ozone can inactivate a range of microorganisms under properly designed treatment conditions.
This is one reason ozone is used in municipal and bottled-water treatment.
However, effective disinfection depends on dose, contact time, water quality, and system design.
Oxidation of Iron and Manganese
Dissolved iron and manganese can sometimes be oxidized by ozone to less soluble forms.
Once oxidized, these particles generally require removal via downstream filtration.
Ozone, therefore, does not simply make iron or manganese disappear; it changes their chemical form so that another treatment stage can remove them more effectively.
Hydrogen Sulfide and Odor
Ozone can oxidize hydrogen sulfide and other odor-producing compounds under suitable conditions.
This can make ozonation useful in systems designed to address certain taste and odor problems.
Organic Compounds
Ozone can react with some organic compounds in water.
But the degree of treatment varies widely. Ozone should not be assumed to eliminate all organic contaminants.
What Ozone Does Not Automatically Remove
One of the biggest problems with older ozone-water articles is the tendency to describe ozone as though it universally “purifies” water.
It does not.
Ozone treatment should not automatically be assumed to remove:
- Dissolved salts
- Hardness minerals
- All metals
- All PFAS
- Nitrate
- Every pesticide
- Every pharmaceutical compound
- Every volatile organic compound
- All sediment
In many systems, ozonation is one stage in a broader treatment train rather than the only treatment process.
Water-treatment principle: Different technologies address different problems. Ozone may disinfect or oxidize certain substances, while sediment filtration, activated carbon, reverse osmosis, ion exchange, or other processes may be needed for other contaminants.
Does Ozone Leave a Residual in Water?
One of ozone's defining characteristics is that it breaks down relatively quickly.
This can be an advantage because ozone does not generally leave a strong disinfectant taste or odor in finished water.
But it is also a limitation.
After treatment, ozone does not normally provide the same persistent disinfectant protection through miles of distribution pipe as chlorine or chloramine can.
For this reason, some public water systems that use ozone also use an additional disinfectant to maintain protection throughout the distribution network.
What Is Bromate?
Bromate is one of the most important concerns associated with drinking-water ozonation.
If the source water contains bromide, ozone can oxidize bromide through a series of reactions that may eventually produce bromate.
Bromate is an unwanted disinfection byproduct and is regulated in drinking water.
This means ozonation cannot simply be approached as “the more ozone, the better.”
Operators must balance:
- Required disinfection
- Oxidation goals
- Source-water bromide
- Ozone dose
- pH
- Temperature
- Contact time
- Other water chemistry
Bromate formation is one reason professional ozone systems require careful process control. Ozonation can create byproducts depending on the chemistry of the source water.
Is Ozonated Water Safe to Drink?
Water treated with ozone can be used as drinking water when the treatment process is properly designed, operated, and monitored and the finished water meets applicable drinking-water requirements.
That does not mean that simply bubbling ozone through any water source automatically makes it safe to drink.
Appropriate treatment depends on:
- The original water quality
- Microbial risks
- Chemical contaminants
- Potential disinfection byproducts
- Ozone dose
- Post-treatment filtration
- Testing and monitoring
Commercial bottled-water facilities and municipal treatment plants use controlled treatment systems rather than simple household-style ozone bubbling.
Does Ozonated Water Have Special Health Benefits?
This is where marketing claims often move far beyond the evidence.
There is no good basis for describing ordinary ozonated drinking water as a proven way to:
- Treat or prevent cancer
- Increase oxygen delivery to the brain
- Boost immunity
- Reduce arthritis
- Treat urinary infections
- Improve gut health
- Cause weight loss
- Reduce systemic inflammation
- “Detoxify” the body
Research involving ozone in specialized medical or dental settings should not be generalized into claims that drinking ozonated water provides the same effects.
Those are separate applications with different doses, exposure methods, treatment protocols, and research questions.
Ozone's strongest established role here is water treatment—not turning drinking water into a therapeutic beverage.
Ozone in Dentistry and Medical Research
Ozone has been studied in specialized dental and medical applications.
However, evidence from a clinical procedure involving ozone gas, ozonated oil, or locally applied ozonated water should not automatically be used to claim that everyday consumption of ozonated water treats disease.
The route of administration and intended use matter.
For a consumer drinking-water article, these specialized applications are best treated as separate research topics rather than promoted as benefits of drinking ozonated water.
Ozone in Bottled Water
Ozone is commonly used in bottled-water operations as an antimicrobial treatment.
One reason it is attractive in bottled-water production is that it can provide disinfection without leaving the persistent taste and odor sometimes associated with chlorine.
Ozone then decomposes rather than remaining indefinitely in the bottled product.
This is a controlled manufacturing application—not a claim that ozonated water in bottles provides special health benefits.
Ozone in Food Processing
Ozone can also be used in food-processing operations, including treatment of water used to wash fruits and vegetables.
Its antimicrobial properties can help control microorganisms on equipment, food-contact surfaces, and processing water when applied under appropriate conditions.
Again, this is a sanitation application rather than a nutritional benefit of ozone.
Advantages of Ozone Water Treatment
When used appropriately, ozone offers several practical advantages.
- Strong oxidation: Ozone reacts rapidly with many compounds.
- Effective disinfection: It can inactivate microorganisms under suitable treatment conditions.
- Useful for iron and manganese oxidation: Oxidized particles can then be removed downstream.
- Can address some tastes and odors: Particularly where oxidizable compounds are responsible.
- No long-lasting ozone residual: Ozone naturally decomposes after treatment.
- Generated on site: Large quantities of disinfectant do not need to be stored and transported as some chemicals do.
Disadvantages of Ozone Water Treatment
Ozone also has important limitations.
- Higher equipment complexity: Ozone must be generated, transferred, monitored, and safely vented or destroyed.
- Ozone gas is hazardous to breathe: Equipment must control leaks and off-gas.
- Bromate can form: Source water containing bromide requires careful process control.
- No residual disinfectant: The water can be recontaminated after ozone has decomposed.
- Often requires additional filtration: Oxidized iron, manganese, or other particles must still be removed.
- Not a universal chemical-removal system: Other technologies may be required.
- Maintenance requirements: Generators, injectors, contact systems, monitors, and off-gas equipment require upkeep.
Ozone vs. Chlorine
| Feature | Ozone | Chlorine |
|---|---|---|
| Disinfection | Strong disinfectant under controlled conditions | Widely used disinfectant |
| Residual protection | Little lasting residual | Can provide residual protection in distribution systems |
| Taste/odor | Ozone itself decomposes relatively quickly | Residual chlorine may affect taste or odor |
| Byproducts | Bromate can form when bromide is present | Can form regulated chlorinated disinfection byproducts |
| Storage | Usually generated on site | Chemical supply is commonly stored and dosed |
Neither technology is universally superior. Water-treatment plants often choose combinations of processes based on the source water and distribution system.
Ozone vs. UV Water Treatment
Ozone and ultraviolet treatment are both used for disinfection, but they work differently.
UV treatment exposes water to ultraviolet light without intentionally adding a chemical oxidant.
Ozone treatment dissolves a reactive oxidizing gas into the water.
Both can provide effective disinfection under appropriate conditions, but neither normally leaves a strong long-lasting disinfectant residual.
Ozone also has a stronger role in chemical oxidation, while UV is primarily used for microbial inactivation unless incorporated into more advanced oxidation processes.
Ozone vs. Activated Carbon
Ozone and activated carbon perform different functions.
Ozone reacts chemically with substances through oxidation.
Activated carbon can adsorb or otherwise interact with selected organic compounds, tastes, odors, and other substances depending on the media and system design.
In some treatment systems, ozonation and activated carbon are used together.
Ozone may first transform certain compounds, while biological or activated-carbon filtration provides downstream treatment.
Ozone vs. Reverse Osmosis
Reverse osmosis uses pressure to push water through a semipermeable membrane.
RO is particularly relevant to many dissolved substances that ozone does not simply remove.
Ozone, by contrast, is primarily used for disinfection and oxidation.
Comparing the two as though they perform the same job is therefore misleading.
If you're comparing water-treatment approaches more broadly, see our Types of Drinking Water Filtration Systems guide.
Can You Use an Ozone Generator at Home?
Residential ozone water-treatment equipment exists, but homeowners should distinguish between professionally designed water-treatment equipment and ozone generators marketed for general air use or improvised treatment.
A water-treatment ozone system needs to account for:
- Correct ozone dosage
- Gas transfer
- Contact time
- Off-gas safety
- Water chemistry
- Post-filtration
- Byproduct formation
This is especially important when the water will be used for drinking.
Do not assume that running a generic ozone generator into a container of water produces properly treated drinking water. Treatment performance and safety depend on controlled system design and source-water chemistry.
Does Ozone Increase Oxygen in Drinking Water?
Because ozone decomposes into oxygen, ozonation can affect dissolved oxygen levels in treated water.
But this does not mean that drinking ozonated water meaningfully “oxygenates the brain” or replaces the role of the lungs.
Humans obtain the overwhelming majority of oxygen used for metabolism through breathing. Oxygen is transferred from the lungs into the bloodstream and carried by hemoglobin.
Claims that ozonated drinking water substantially increases oxygen delivery throughout the body should therefore be treated skeptically.
Can Ozonated Water Be Stored?
Ozone is unstable in water and gradually decomposes.
Its concentration therefore decreases with time, with the rate depending on factors such as:
- Temperature
- pH
- Organic matter
- Water chemistry
- Container conditions
This means “ozonated water” does not remain highly ozonated indefinitely after treatment.
FAQ: Ozone Water Treatment
What is ozone water?
Ozone water, or ozonated water, is water into which ozone gas has been dissolved. Ozone reacts rapidly with microorganisms and selected substances before gradually decomposing.
What is ozone used for in water treatment?
Ozone can be used for disinfection and oxidation. Depending on system design, it may inactivate microorganisms, oxidize iron and manganese, address hydrogen sulfide, and reduce some taste and odor compounds.
Does ozone remove everything from water?
No. Ozone is not a universal contaminant-removal process. Additional technologies may be necessary for dissolved salts, hardness, nitrate, sediment, PFAS, metals, and other contaminants.
Is ozonated water safe to drink?
Water treated with ozone can be used as drinking water when treatment is properly designed, and the finished water meets applicable quality requirements. Simply adding ozone to unknown water does not automatically make it appropriate for drinking.
Does ozone remain in drinking water?
Ozone is unstable and breaks down relatively quickly. This means it typically provides little lasting disinfectant residual after treatment.
What is bromate?
Bromate is a disinfection byproduct that can form when ozone reacts with bromide in source water. Controlling bromate formation is an important part of professional ozonation system design.
Does ozone remove iron?
Ozone can oxidize dissolved iron into less-soluble particles. Those particles generally need to be removed afterward using appropriate filtration.
Does ozone remove manganese?
Ozone can oxidize manganese under suitable conditions, after which downstream filtration may be needed to remove the resulting particles.
Does ozone remove chlorine?
Ozone is not usually selected simply as a household chlorine-removal method. Activated carbon is a more conventional approach for reducing chlorine taste and odor in drinking water.
Does ozone kill microorganisms?
Ozone is a strong disinfectant and can inactivate microorganisms when appropriate ozone dose and contact conditions are achieved.
Is ozone better than chlorine?
Neither is universally better. Ozone is a strong oxidant and disinfectant but leaves little persistent residual, while chlorine can provide continued disinfection through a distribution system. Each also has different potential byproducts.
Does drinking ozonated water provide health benefits?
There is not strong evidence supporting broad claims that ordinary ozonated drinking water treats cancer, boosts immunity, improves oxygen delivery, causes weight loss, or provides other therapeutic benefits often promoted online.
The Bottom Line
Ozone is a legitimate and powerful water-treatment technology, but it is best understood as a disinfectant and oxidizing agent rather than as a special health ingredient in drinking water.
Properly designed ozone systems can inactivate microorganisms and oxidize substances such as iron, manganese, hydrogen sulfide, and selected organic compounds.
At the same time, ozone has important limitations. It does not automatically remove every dissolved contaminant; it provides little lasting disinfectant residual; ozone gas must be handled safely; and bromate can form when bromide is present in the source water.
The best treatment systems therefore use ozone where it makes sense and combine it with other technologies when additional treatment is required.
Ozone is valuable for what it does in controlled water treatment—not because ozonated water has been proven to be a therapeutic health drink.