How to Remove Chlorine From Water (and Chloramine): Every Method Compared
By SubcontractorHub Editorial Team·Published September 2026
Short version: first find out whether your utility uses chlorine or chloramine, because the answer changes everything. Free chlorine leaves water if you let it sit for about 24 hours or boil it for 15 to 20 minutes, and almost any carbon filter removes it. Chloramine barely responds to either; it needs catalytic carbon with longer contact time, a reverse osmosis system with the right pre-filter, or vitamin C for small batches. A water softener removes neither, and chlorine shortens the life of its resin.
Chlorine is in tap water on purpose. Utilities add it to kill pathogens and keep a small residual all the way to your faucet, and that residual is why public water in the United States does not spread cholera or typhoid. The EPA caps it with a maximum residual disinfectant level of 4 mg/L for both chlorine and chloramine, and most systems run well below that. Chlorinated tap water is safe to drink.
People remove it anyway for good reasons: the taste and swimming-pool smell, dry skin and hair in the shower, fish tanks and ponds, and home brewing. This guide covers what actually works, how long it takes, and what to install if you want it gone from the whole house. It is written for homeowners and for the water treatment and water purification dealers who get asked about it every week.
1. Chlorine vs Chloramine: Check This First
Utilities use one of two disinfectants. Free chlorine is chlorine gas, sodium hypochlorite or calcium hypochlorite dissolved in water. It is effective but volatile, which is why it fades in long pipe networks. Chloramine (monochloramine) is made by adding ammonia to chlorine. It is weaker but far more stable, lasts longer in the distribution system and forms fewer regulated disinfection byproducts, so many large US utilities have switched to it. The CDC estimates that more than one in five Americans drink chloraminated water.
That stability is exactly what makes chloramine hard to remove at home. To find out which you have, check your utility’s annual Consumer Confidence Report (water quality report), which lists the disinfectant and measured residual. A free-and-total chlorine test strip also helps: total chlorine far above free chlorine usually means chloramine. Note that many chloraminated systems switch to free chlorine for a few weeks each year to clean the mains, which is when customers suddenly notice a strong smell.
2. Every Method Compared
The table covers the common options. Costs are typical US ranges for equipment and vary with brand, installation and local labor.
Rule of thumb: every method that removes chloramine also removes chlorine, but most methods that remove chlorine do little for chloramine.
3. The Free Methods: Letting Water Sit and Boiling
Does boiling water remove chlorine?
Yes, if it is free chlorine. A rolling boil for about 15 to 20 minutes drives off most of it. Leaving a pitcher or bucket uncovered for roughly 24 hours does the same job with no energy, and it goes faster in a wide container or if you stir it. Both are fine for a jug of drinking water or topping up a small tank.
Neither is a real answer for chloramine, which can persist for days in an open container and needs an impractically long boil to reduce. Boiling also concentrates what does not evaporate, including nitrate, lead and minerals, so it is a taste fix, not purification.
Vitamin C
Ascorbic acid and sodium ascorbate neutralize both chlorine and chloramine almost instantly. A commonly cited figure is that about 1,000 mg of vitamin C dechlorinates a full bathtub, and utilities use it to dechlorinate water flushed from mains. It is the best option for baths and the active ingredient in vitamin C shower filters. For aquariums, use a conditioner labeled for chloramine: breaking chloramine apart releases ammonia, which is toxic to fish, and those conditioners bind it.
4. Filters: Carbon, Catalytic Carbon, RO and KDF
Activated carbon removes chlorine by reacting with it on the carbon surface, and it works fast. Pitcher and faucet filters certified to NSF/ANSI 42 for chlorine taste and odor are enough for drinking water on a chlorinated system. Chloramine reacts far more slowly, so a small cartridge often lets a lot of it through. If you are on chloramine, look for a data sheet that specifically claims chloramine reduction.
For the whole house, standard granular activated carbon (GAC) handles chlorine well. For chloramine, the industry answer is catalytic carbon, a carbon whose surface has been modified to break chloramine down much faster, combined with a bigger bed or slower flow so the water spends longer in contact with it. The whole house water filter cost calculator estimates installed pricing.
Reverse osmosis systems include carbon pre- and post-filters, and the pre-filter matters: chlorine damages the thin-film membrane, so the carbon stage protects it. On chloramine, specify a catalytic pre-filter. RO also removes fluoride and dissolved solids; see how to remove fluoride from water and the reverse osmosis system cost calculator.
KDF, a copper-zinc media, converts free chlorine and holds up well in hot water, which is why it shows up in shower filters, usually beside carbon. It does little for chloramine. UV disinfects microbes and does not remove either disinfectant at residential doses.
5. Does a Water Softener Remove Chlorine?
No. A softener exchanges hardness minerals for sodium or potassium on ion exchange resin, and chlorine passes straight through. Chlorine and chloramine are oxidizers, and over time they attack the cross-linking that holds the resin beads together. The beads swell, turn mushy, pack down and lose capacity, and the resin wears out years earlier than it would on unchlorinated well water.
The fix is a carbon filter ahead of the softener, which removes the chlorine and protects the resin, or a more oxidation-resistant 10% cross-link resin. If a softener is already failing early, the water softener resin replacement guide covers the signs. For how the two systems split the work, see water softener vs reverse osmosis.
6. Worked Example: Sizing a Whole-House Carbon System
Whole-house carbon is sized by empty bed contact time (EBCT): the volume of carbon divided by the flow rate. Undersize the bed and water rushes through at peak demand, so chlorine or chloramine gets past. Common rules of thumb are around 5 gpm per cubic foot of standard GAC for chlorine and around 2.5 gpm per cubic foot of catalytic carbon for chloramine; always check the media manufacturer’s rated service flow.
House: 3 bathrooms, peak demand about 8 gpm
Chlorine, standard GAC: 8 gpm ÷ 5 gpm/ft³ = 1.6 ft³ of carbon, EBCT about 1.5 minutes (1.6 ft³ × 7.48 gal ÷ 8 gpm)
Chloramine, catalytic carbon: 8 gpm ÷ 2.5 gpm/ft³ = 3.2 ft³ of carbon, EBCT about 3 minutes (3.2 ft³ × 7.48 gal ÷ 8 gpm)
The same house needs roughly two and a half times the media for chloramine, which usually means a much larger tank or two tanks in series, and it is why chloramine quotes come in higher. Run your own numbers in the carbon filter sizing calculator.
For Water Treatment Dealers
Chloramine conversions create demand. When a utility switches, customers notice a different taste, aquarium owners lose fish, and existing chlorine-only carbon systems stop performing even though nothing looks wrong. Every one of those homes needs a catalytic carbon upgrade or media change, and every softener on that system is now losing resin life faster.
The durable revenue is in the service plan: scheduled carbon media replacement, pre-filter changes and resin checks sold as an annual agreement rather than a one-off call. Tracking which neighborhoods are on which utility, and when they convert, turns a public notice into a marketing list. Much of the install is plumbing work: bypass loops, tank placement and drain runs.
SubcontractorHub is software for water treatment dealers: quotes that show the chlorine or chloramine finding, good-better-best system options, financing, e-signature and recurring service scheduling in one place.
Frequently Asked Questions
Does boiling water remove chlorine?
Yes, for free chlorine. A rolling boil for about 15 to 20 minutes drives off most free chlorine, and simply leaving an open container out for around 24 hours does much the same thing more slowly. Boiling does not work well on chloramine, which is far more stable and can take a very long boil to reduce meaningfully. Boiling also concentrates anything that does not evaporate, such as nitrate, lead and dissolved minerals, so it is a way to remove chlorine taste, not a way to purify water.
Does a water softener remove chlorine?
No. A water softener uses ion exchange resin to swap calcium and magnesium for sodium or potassium, and that process does nothing to chlorine or chloramine. Worse, chlorine and chloramine are oxidizers that slowly break down the cross-linking in softener resin, causing it to swell, turn mushy and lose capacity years early. On chlorinated city water, a carbon filter installed ahead of the softener removes the chlorine and protects the resin. Some combination units put a carbon layer in the same tank for the same reason.
How do you remove chloramine from water?
Use catalytic carbon, give it enough contact time, or use vitamin C for small batches. Catalytic carbon is activated carbon whose surface has been modified to break chloramine down much faster than standard granular activated carbon, and whole-house systems for chloramine are typically sized with a larger bed and slower flow than chlorine-only systems. Reverse osmosis systems with a catalytic carbon pre-filter handle it at the drinking tap. Vitamin C in the form of ascorbic acid or sodium ascorbate neutralizes chloramine in bath water. Letting water sit and boiling it are not practical for chloramine.
How do I know if my water has chlorine or chloramine?
Check your water utility's annual Consumer Confidence Report, also called a water quality report, which lists the disinfectant used and the residual levels measured. You can also call the utility or look on its website. Pool-style test strips that read free and total chlorine help too: if total chlorine is much higher than free chlorine, the residual is mostly combined chlorine, which usually means chloramine. Many utilities also switch temporarily from chloramine to free chlorine for a few weeks a year, so the answer can change seasonally.
Is chlorine in tap water safe to drink?
Yes, at the levels utilities use. The EPA sets a maximum residual disinfectant level of 4 mg/L for both chlorine and chloramine, measured as chlorine, and typical tap water is well below that. Disinfection is the reason public water does not spread waterborne disease. Most people remove chlorine for taste and odor, for skin and hair in the shower, or because it matters for a specific use: aquariums and ponds, some home brewing, and kidney dialysis, which is handled by the dialysis provider.
Do pitcher filters remove chloramine?
Some do, many are not certified to. Most pitcher and faucet filters are certified under NSF/ANSI 42 for chlorine taste and odor, which is a different claim from chloramine reduction. If your utility uses chloramine, look for a filter whose performance data sheet specifically lists chloramine reduction, and replace the cartridge on schedule, because the small amount of carbon in a pitcher cartridge is used up faster by chloramine than by free chlorine.
Related Guides & Tools
- Whole House Water Filter Cost Calculator
- Reverse Osmosis System Cost Calculator
- Water Softener vs Reverse Osmosis
- Water Softener Resin Replacement
- → SubcontractorHub for Plumbing
- → Water Treatment and Water Purification Contractor Software
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