Chloramine in Drinking Water: A Complete Homeowner's Guide
Most people do not think much about what comes out of the kitchen faucet until the taste, smell, or appearance of their water changes.
Over the past several decades, many public water systems have adopted chloramine because it can maintain a disinfectant residual longer than free chlorine as treated water moves through the distribution system.
For many households, the change is barely noticeable. Others become curious about how chloramine differs from chlorine, whether it affects taste and odor, and what options are available if they prefer to reduce it from drinking water.
Quick answer: Chloramine is a disinfectant used by many public water systems. It is generally more stable and longer-lasting than free chlorine, which makes it useful in large distribution networks. If your goal is to reduce chloramine at home, simply letting water sit is usually not enough; use a treatment method specifically designed and tested for chloramine reduction.
What Is Chloramine?
Chloramine is formed when chlorine reacts with a controlled amount of ammonia during drinking-water treatment.
Several chloramine compounds can exist, but the form most commonly used by public water systems is monochloramine.
Utilities use monochloramine because it is relatively stable and can remain in treated water as it moves through long networks of pipes.
This helps maintain a disinfectant residual farther from the treatment plant.
Why Do Water Utilities Use Chloramine?
Free chlorine has been used for drinking-water disinfection for many decades. It acts relatively quickly and remains an important treatment tool.
But once treated water enters a distribution system, utilities still need to maintain water quality as it moves through:
- Water mains
- Storage tanks
- Neighborhood distribution pipes
- Long-distance networks
Chloramine has an advantage in these settings because it generally persists longer than free chlorine.
Utilities may also use chloramine as part of a strategy to manage certain disinfection byproducts that can form when chlorine reacts with naturally occurring organic matter.
Not every city uses chloramine. Utilities choose disinfectants according to source-water chemistry, infrastructure, regulatory requirements, distribution-system conditions, and treatment goals.
Chloramine vs. Chlorine: What's the Difference?
Chlorine and chloramine are both used as drinking-water disinfectants, but they behave differently.
| Characteristic | Free Chlorine | Chloramine |
|---|---|---|
| Reaction speed | Acts relatively quickly | Generally reacts more slowly |
| Persistence | Dissipates more readily | Remains in water longer |
| Distribution use | Common in many systems | Useful where a longer-lasting residual is desirable |
| Taste and odor | Can produce a noticeable chlorine taste or smell | May be less noticeable to some people, although sensitivity varies |
| Removal by standing | Can dissipate more readily | Does not dissipate nearly as easily |
Neither disinfectant is universally better. Water utilities select treatment strategies that fit their own source water and distribution system.
If your utility uses chlorine instead, see our Chlorine in Drinking Water Guide.
Why Doesn't Chloramine Fade as Quickly as Chlorine?
One practical difference becomes obvious when water is allowed to sit.
Free chlorine can gradually dissipate from water exposed to air. Chloramine is more stable, so leaving water in an open pitcher overnight generally does not reduce it nearly as effectively.
This stability is useful for utilities because it helps maintain a disinfectant residual throughout the distribution system.
It also means homeowners need to use a treatment method specifically suited to chloramine if reduction is the goal.
Can You Remove Chloramine by Boiling Water?
Boiling is not a practical, general household method for reducing chloramine.
While heat and prolonged aeration can affect chloramine chemistry, boiling drinking water simply to address chloramine is inefficient and does not provide the same predictable treatment as a properly designed filtration system.
Chloramine behaves differently from free chlorine. Methods that work reasonably well for reducing free chlorine—such as simply letting water stand—should not automatically be assumed to work for chloramine.
Why Do Some People Notice Chloramine More Than Others?
People vary in their sensitivity to taste and odor.
Some households may not notice any difference when a utility changes disinfectants. Others may describe:
- A faint chemical taste
- A medicinal note
- A subtle pool-like aroma
- A difference in coffee or tea
Local water chemistry also matters.
Seasonal changes in source water, treatment adjustments, pipe conditions, and other dissolved substances can influence how tap water tastes.
That means an unusual taste is not proof that chloramine concentration suddenly increased.
What Does EPA Say About Chloramine?
Chloramine is not an accidental contaminant. It is intentionally used by many public water systems for drinking-water disinfection.
For chloramine, the federal Maximum Residual Disinfectant Level is 4.0 mg/L as chlorine.
Public water systems monitor disinfectant levels as part of their treatment and distribution operations.
Important distinction: Chloramine is intentionally added for disinfection. That is different from contaminants that enter water unintentionally through pollution, plumbing, industrial activity, or natural geology.
Why Do Some Households Choose to Reduce Chloramine?
For many homeowners, chloramine reduction is primarily about taste and preference.
Filtered water may be preferred for:
- Drinking
- Coffee
- Tea
- Cooking
- Ice
Other households are satisfied with their municipal water as supplied.
The right choice depends on your local water, your preferences, and what you expect from a filtration system.
How Can You Tell If Your Water Contains Chloramine?
The easiest way to find out is to check with your water utility.
Start with your annual Consumer Confidence Report (CCR).
The report typically provides information about:
- Your drinking-water source
- Treatment practices
- Regulated contaminants detected during monitoring
- Disinfectants and disinfection byproducts
You can also contact the utility directly and ask whether it uses:
- Free chlorine
- Chloramine
- A seasonal combination or switching strategy
This is more reliable than trying to identify chloramine by taste or smell alone.
Situations Where Chloramine Requires Extra Attention
Aquariums
Fish and other aquatic organisms can be sensitive to chlorine and chloramine.
Do not assume ordinary municipal tap water can be added directly to an aquarium without appropriate preparation.
Aquarium owners typically use water conditioners or other treatments intended to neutralize chloramine before adding new tap water.
Home Dialysis
People receiving dialysis at home should follow the water-treatment requirements provided by their healthcare team and equipment manufacturer.
Dialysis water requires specialized treatment and monitoring that are very different from those for ordinary household drinking water filtration.
Laboratory and Industrial Uses
Some laboratories, manufacturing processes, food-production systems, and other specialized applications require tightly controlled water chemistry.
In those cases, treatment should be designed for the process requirements rather than for ordinary drinking-water taste.
How Can Chloramine Be Reduced at Home?
Several treatment technologies can be used for chloramine, but performance depends strongly on filter design and contact time.
Activated Carbon
Activated carbon is widely used for drinking-water treatment.
Chloramine is generally more difficult to reduce than free chlorine, so not every basic carbon filter provides the same chloramine performance.
When chloramine is a specific concern, look for:
- Documented chloramine reduction
- Adequate carbon media
- Sufficient contact time
- Appropriate flow rate
- Clear replacement guidance
Catalytic Carbon
Catalytic activated carbon is often used in systems specifically designed for chloramine treatment because it can promote chloramine decomposition more effectively than certain conventional carbon configurations.
Reverse Osmosis
Reverse-osmosis systems commonly use carbon pretreatment stages before the RO membrane.
The carbon stages are particularly important when chloramine is present, as the membrane itself should not be viewed as the sole treatment stage.
If you're comparing treatment options, see our Types of Drinking Water Filtration Systems guide.
Do not assume that any carbon filter automatically provides meaningful chloramine reduction. Look for performance information for the exact product and replace the media according to its specified service life.
Berkey® Water Filters and Chloramine
Berkey® systems are countertop gravity-fed filters that operate without electricity or permanent plumbing.
Chloramine performance depends on the specific filter element installed.
Published testing for Black Berkey® Elements includes chloramine reduction. Phoenix Gravity New Millennium Edition™ Filters also include chloramine performance information as part of their available testing.
If chloramine reduction is one of your priorities, review the current test information for the exact filter before choosing a configuration.
You can review available filter-performance information on our Water Filter Test Results page.
Choosing the system size comes second. First choose a filter element appropriate to your source water and filtration goals. Then choose the stainless-steel Berkey® vessel that provides the capacity your household needs.
Choosing the Right Berkey® System Size
If you decide a gravity-fed Berkey® system fits your household, system size is mainly a question of storage capacity, countertop footprint, and daily water use.
| System | Capacity | Typical Fit |
|---|---|---|
| Travel Berkey® | 1.5 gallons | Individuals, couples, smaller spaces |
| Big Berkey® | 2.25 gallons | Everyday household use |
| Royal Berkey® | 3.25 gallons | Families wanting greater capacity |
| Imperial Berkey® | 4.5 gallons | Higher daily water use |
| Crown Berkey® | 6 gallons | Large households and shared spaces |
For dimensions, household recommendations, and current filter configurations, see our Berkey Water Filter Systems comparison guide.
Chloramine and Disinfection Byproducts
One reason utilities may consider chloramination is to help manage the formation of certain regulated disinfection byproducts associated with chlorination.
However, chloramination has its own water-chemistry considerations and does not eliminate the broader issue of disinfection byproducts.
Related compounds and topics include:
Utilities balance microbial control, residual disinfectant, source-water chemistry, and byproduct formation when selecting treatment strategies.
What If Your Tap Water Suddenly Tastes Different?
A change in taste or odor does not automatically mean the water is unsafe or that chloramine has suddenly appeared.
Possible reasons include:
- Seasonal changes in source water
- A change from free chlorine to chloramine
- Temporary treatment adjustments
- Changes in reservoir conditions
- Plumbing conditions inside the building
- Changes in water temperature
If the change is strong, sudden, persistent, or accompanied by unusual color or sediment, contact your water utility rather than trying to diagnose the problem from taste alone.
Frequently Asked Questions
Does every city use chloramine?
No. Some utilities use free chlorine, some use chloramine, and some may change treatment approaches depending on operating conditions.
Why would one utility choose chloramine instead of chlorine?
Utilities consider source-water chemistry, distribution-system size, disinfectant persistence, infrastructure, regulatory requirements, and disinfection-byproduct management when choosing a treatment strategy.
Is chloramine the same as chlorine?
No. Chloramine is formed by combining chlorine and ammonia under controlled treatment conditions. It is generally more stable and persistent than free chlorine.
Can you smell chloramine?
Some people notice a chemical or medicinal taste or odor, while others notice little or nothing. Smell alone cannot tell you whether your water contains chloramine or how much it contains.
Can I remove chloramine by leaving water out overnight?
Not effectively in the way people commonly use this method for free chlorine. Chloramine is considerably more stable.
Does boiling water remove chloramine?
Boiling is not a practical, general household chloramine treatment method. A filtration system specifically designed for chloramine reduction is a more predictable approach.
Does activated carbon reduce chloramine?
Some activated-carbon systems can reduce chloramine, but effectiveness varies substantially with carbon type, media quantity, contact time, flow rate, and filter condition.
Is catalytic carbon better for chloramine?
Catalytic carbon is commonly used when chloramine reduction is a specific treatment goal, as it is designed to enhance the reactions involved in chloramine decomposition.
How can I find out whether my water contains chloramine?
Check your public water system's annual Consumer Confidence Report or contact the utility directly.
Why is chloramine important for aquarium owners?
Fish and other aquatic organisms can be sensitive to chlorine and chloramine. Aquarium water should be treated using a method appropriate for chloramine before municipal tap water is introduced.
Is chloramine important for home dialysis?
Yes. Dialysis water requires specialized treatment. Anyone receiving dialysis at home should follow the water-treatment requirements provided by the healthcare team and equipment manufacturer.
Do Black Berkey® Elements reduce chloramine?
Published performance information for Black Berkey® Elements includes chloramine reduction. Review the current documentation for the exact filter element and its operating conditions.
Do Phoenix Gravity filters reduce chloramine?
Phoenix Gravity New Millennium Edition™ Filters include chloramine performance information in their available test results. Review the current test-results page for details.
When should a chloramine filter be replaced?
Follow the replacement or rated-capacity guidance for the specific filter. Chloramine performance depends on adequate media and contact time, so filters should not be operated indefinitely beyond their intended service life.
Final Thoughts
Chloramine is an intentional part of drinking-water treatment in many communities.
Its main advantage for utilities is persistence: it can maintain a disinfectant residual longer than free chlorine as water moves through the distribution system.
For homeowners, the most useful first step is simply finding out whether their utility uses chloramine.
If your goal is to reduce it, choose a filter with documented chloramine performance rather than assuming that standing water, boiling, or any generic carbon filter will provide the same result.
Know what your utility uses, understand what your filter is designed to do, and base treatment decisions on documented performance for the exact filter element.