Ozone water is water that has been treated with ozone gas, an unstable molecule composed of three oxygen atoms (\(\text{O}_3\)). This treatment method has been used in Europe for over a century and is increasingly common in municipal and bottled water systems worldwide. The core question is whether this powerful disinfecting agent remains in the water and poses a health risk by the time it reaches the consumer.
Understanding Ozone and Ozonation
Ozone (\(\text{O}_3\)) is an allotrope of oxygen, possessing a high degree of instability and reactivity. It is artificially generated on-site at water treatment facilities, typically by passing oxygen through a high-voltage electrical discharge, similar to the way lightning creates ozone in the atmosphere, or by using ultraviolet light. The resulting gas is then dissolved into the water in a process called ozonation.
The high reactivity of the ozone molecule makes it effective for purification and ensures its safety in the final product. Unlike more stable disinfectants, ozone readily degrades back into its stable form of two oxygen atoms (\(\text{O}_2\)). This decomposition occurs rapidly, often within minutes or even seconds, depending on the water’s temperature and composition. The ozone molecule itself does not persist for long in the treated water, which differentiates it from other chemical treatments.
The Primary Function: Disinfection and Purification
Ozone is introduced into water because it is an extremely potent oxidizing agent, stronger and faster-acting than traditional chlorine. This power allows it to effectively destroy a broad spectrum of waterborne pathogens, including bacteria, viruses, and protozoa, by breaking down their cell walls and genetic material. Ozonation is often employed as a primary disinfectant in municipal systems and is highly effective across a wide range of water pH levels.
The oxidation process also removes inorganic contaminants like iron and manganese, converting them into insoluble particles that can be easily filtered out. A significant advantage of ozonation over chlorination is its potential to reduce the formation of harmful disinfection byproducts (DBPs). While chlorine can react with organic matter to form compounds like trihalomethanes, ozone generally avoids creating these specific halogenated byproducts. Ozone can still produce other oxygenated byproducts, such as aldehydes and ketones, which are monitored and removed by subsequent filtration steps.
Safety of Consuming Treated Water
Water treated with ozone in municipal or bottled water plants is widely considered safe for consumption. This safety stems from the inherent instability of the ozone molecule, meaning that virtually no residual ozone remains by the time the water reaches the tap or bottle. The U.S. Food and Drug Administration (FDA) and the World Health Organization (WHO) have approved ozone for use in food processing and water treatment.
Regulatory bodies set strict standards for residual ozone, with the WHO recommending that the concentration in drinking water be controlled below 0.4 parts per million (ppm). At these low, transient levels, the remaining ozone quickly decomposes into oxygen after ingestion. Toxicity arises only when consuming water with high concentrations of dissolved ozone, such as that generated by some point-of-use home devices. Ingesting highly ozonated water can cause irritation to the mucous membranes of the mouth and stomach lining.
It is important to differentiate between professionally treated water and water from unregulated home systems. When ozonation is properly controlled and monitored, the final product is safe because the rapid decay of ozone ensures it performs its disinfecting function without leaving a persistent, toxic residue.
Examining Health Claims and Misconceptions
Despite the science confirming the safety of conventionally ozonated drinking water, highly ozonated water is often promoted with unsupported health claims. These claims suggest that drinking the water can provide “super-oxygenation,” “detoxification,” or “immune-boosting” effects, based on the idea that extra oxygen from the decomposed ozone will enhance the body’s oxygen levels.
The scientific evidence does not support these claimed internal benefits. Ozone’s instability means that any residual ozone breaks down immediately upon contact with organic matter in the digestive tract, preventing it from delivering an effective “oxygen boost” to the bloodstream. While ozone is a potent antimicrobial agent used topically in dentistry or wound care, these external applications do not translate into systemic health benefits when drinking the water. Medical ozone therapy, which involves the external or intravenous application of ozone under highly controlled conditions, is a separate, regulated, and often controversial practice entirely distinct from consuming ozonated drinking water.