An ozone generator produces ozone from air or oxygen and dissolves it into water, where it acts as a very strong oxidizing agent. It kills bacteria, oxidizes iron, manganese and hydrogen sulfide, and then decomposes back to ordinary oxygen leaving no chemical residue at all. That last property is why it is attractive and also why it has a hard limit.
What ozone does in water
It oxidizes fast and thoroughly. Dissolved iron and manganese convert to particles a filter downstream can catch, hydrogen sulfide is destroyed rather than merely stripped, and bacteria and viruses are inactivated. It also breaks down many organic compounds that cause taste and odor, and it destroys the sulfur bacteria that keep regenerating a smell after other treatments appear to have worked. On the well water complaints it addresses, it is genuinely one of the most capable options available.
The residual problem
Ozone is unstable and decomposes within minutes, which is its great advantage on taste and its fundamental limitation on protection. There is no residual left in the plumbing, so anything that contaminates the water after the contact tank is not dealt with, and stored water can be recolonized. Chlorination leaves a residual that keeps working through the distribution pipework; ozone does not. That makes it excellent as a treatment step and unsuitable as the only barrier on a system with storage downstream.
What has to be built around it
A generator, a way of dissolving the gas into the water efficiently, usually a venturi injector, and a contact tank giving time for the reactions to complete. Then a filter to remove everything the ozone oxidized, because dissolved iron converted to particles must be caught or it simply deposits further downstream. Then, often, carbon to polish. Off gas from the contact tank must be vented safely, since ozone is a respiratory irritant and should not accumulate in a utility room.
How it compares
Against chlorination it is stronger, faster and leaves no taste or chloride, but costs more, needs power continuously and provides no residual. Against ultraviolet it is far more capable, since UV inactivates organisms and removes nothing, while ozone also handles iron, manganese and sulfide. Against aeration it is much stronger on manganese, which oxidizes reluctantly with air alone. It is the right answer where multiple oxidation duties exist at once. Our water treatment guide covers matching the method to an analysis.
Questions people ask about water ozone generator
What does ozone remove from water?
It oxidizes iron, manganese and hydrogen sulfide into filterable form and inactivates bacteria and viruses, leaving no chemical residue.
Why does it need a filter after it?
Ozone converts dissolved metals into particles. Without a filter downstream those simply deposit further along the plumbing.
Does it protect stored water?
No. Ozone decomposes within minutes and leaves no residual, so anything contaminating the water afterwards is untreated.
How does it compare with chlorination?
Stronger and faster with no taste or chloride added, but it costs more, needs continuous power and leaves no protective residual.