Hydrogen peroxide is the alternative oxidant on a private well, used where chlorine's residual and taste are unwelcome. It oxidizes hydrogen sulfide, iron and manganese effectively and then decomposes into water and oxygen, leaving nothing behind, which is both its main appeal and the reason the system around it has to be arranged carefully.
What it does and what it leaves
Injected into the line, peroxide converts dissolved hydrogen sulfide into elemental sulfur particles and dissolved iron and manganese into oxidized particles, all of which a filter behind it can catch. Unlike chlorine it adds no chloride, no taste and no lasting residual, because it breaks down to water and oxygen. That means no carbon stage is needed simply to remove a residual, which shortens the train, and it also means there is no protection carried into the household plumbing.
What the system consists of
A solution tank, a metering pump triggered by the well pump or a flow switch, a static mixer so the dose blends at household flow rates, contact time in a retention tank or in the pipework, and a catalytic filter to catch the particles produced. Catalytic carbon is commonly used for that filter because it also helps break down any excess peroxide. Sizing follows the load from a laboratory result, since the dose required depends on how much sulfide and iron the water carries.
Handling it
The peroxide used for water treatment is considerably stronger than the household product, and it deserves respect: it causes chemical burns on skin contact and damages eyes, so gloves and eye protection are not optional when mixing or refilling. Store it in the container it came in, cool and out of sunlight, away from organic material and metals that catalyse its breakdown, and never in a sealed container that cannot vent, since it decomposes and generates pressure. Buy quantities you will use.
Choosing it against chlorination
Peroxide suits a household that dislikes chlorine taste, wants no chloride added, and does not need a residual through storage. Chlorination is cheaper to run, deals with iron and sulfur bacteria more reliably, and leaves a residual that protects the plumbing downstream. Peroxide handles the chemistry well and is less certain against biological growth. The EPA notes private wells are not federally regulated, so testing after installation is the owner's. Our treatment service guide covers dosing systems generally.
Questions people ask about peroxide water treatment
What does peroxide leave in the water?
Nothing lasting. It breaks down into water and oxygen, adding no chloride, no taste and no residual.
Does it need a carbon filter afterwards?
Not to remove a residual, though a catalytic filter is normally fitted to catch the oxidized particles and break down any excess.
Is it safe to handle?
Treatment strength peroxide is much stronger than the household product and causes burns, so gloves and eye protection are essential.
How does it compare with chlorination?
It adds no taste or chloride, but chlorination is cheaper, handles iron and sulfur bacteria more reliably and leaves a protective residual.