Chloramine in Drinking Water: A Complete Homeowner's Guide
Chloramine is a drinking-water disinfectant used by many public water systems, usually as a longer-lasting secondary disinfectant after primary treatment.
It is most commonly formed when ammonia is added to chlorine under controlled treatment conditions. Compared with free chlorine, monochloramine generally persists longer as treated water moves through distribution pipes.
Quick answer: Chloramine is more persistent than free chlorine. If you want to reduce it at home, letting water stand is generally not an effective approach. Choose a treatment method with documented chloramine-reduction performance for the exact filter or media being used.
What Is Chloramine?
Chloramines are formed when ammonia is added to chlorine during drinking-water treatment. Several chloramine compounds can exist, but monochloramine is the form most commonly used for public drinking-water disinfection.
Its stability makes it useful as a secondary disinfectant because it can maintain a residual farther into a distribution network than free chlorine.
Why Do Water Utilities Use Chloramine?
Many public water systems use chlorine during treatment, but utilities also need to maintain water quality after treated water enters storage tanks and distribution pipes. Chloramine can provide a longer-lasting residual and may be used as part of a strategy to manage certain disinfection byproducts.
Not every utility uses chloramine. Treatment choices depend on source-water chemistry, infrastructure, regulatory requirements, distribution conditions, and treatment goals.
Chloramine vs. Chlorine: What's the Difference?
| Characteristic | Free Chlorine | Chloramine |
|---|---|---|
| Reaction speed | Acts relatively quickly | Generally reacts more slowly |
| Persistence | Dissipates more readily | Persists longer in distribution |
| Taste and odor | Can have a noticeable chlorine taste or smell | May be less noticeable to some people; sensitivity varies |
| Standing/aeration | Can dissipate more readily | Does not dissipate nearly as easily |
| Carbon filtration | Generally easier to reduce | Requires chloramine-specific performance and adequate contact time |
If your utility uses free chlorine instead, see our Chlorine in Drinking Water Guide.
What Does EPA Say About Chloramine?
Chloramine is intentionally used for drinking-water disinfection. EPA's federal Maximum Residual Disinfectant Level (MRDL) for chloramines is 4.0 mg/L as Cl₂.
EPA states that water containing chloramines and meeting regulatory standards is suitable for normal household uses such as drinking, cooking, and bathing. Public systems monitor disinfectant levels under the applicable regulatory framework; a single household measurement should not automatically be interpreted as a determination of compliance.
Can You Remove Chloramine by Letting Water Sit or Boiling It?
Leaving water in an open container is not an effective general approach to chloramine because chloramine is substantially more stable than free chlorine.
Boiling is also not a practical general household treatment strategy for chloramine. If reduction is the goal, a filtration method with documented chloramine performance is more predictable.
How Can You Tell If Your Water Contains Chloramine?
Start with your public water system's annual Consumer Confidence Report (CCR) or contact the utility directly. Ask whether the system uses free chlorine, chloramine, or seasonal switching between disinfectants.
Free-chlorine and total-chlorine tests can provide useful screening information, but utility confirmation is the best starting point for identifying the disinfectant in your public water supply.
Situations Where Chloramine Requires Extra Attention
Aquariums
Fish and other aquatic organisms can be sensitive to chlorine and chloramine. Use aquarium-specific conditioning or treatment appropriate for chloramine before introducing municipal tap water.
Home Dialysis
Dialysis water requires specialized treatment and monitoring. Anyone receiving dialysis at home should follow the requirements set by the healthcare team and the equipment manufacturer rather than relying on ordinary household drinking water filtration.
How Can Chloramine Be Reduced at Home?
Activated Carbon
Carbon filtration can reduce chloramine, but performance varies with media type, media quantity, flow rate, contact time, source-water conditions, and filter condition. A generic chlorine claim should not automatically be treated as a chloramine claim.
Catalytic Carbon
Catalytic activated carbon is commonly used when chloramine reduction is a specific treatment goal because it can improve the reactions involved in chloramine decomposition.
Reverse Osmosis Systems
Reverse-osmosis systems commonly include carbon pretreatment. When chloramine is present, the pretreatment stages are important; the membrane itself should not be viewed as the only relevant step in chloramine treatment.
Look for chloramine-specific evidence. Do not assume that every carbon filter provides the same level of chloramine reduction. Review performance information for the exact product and follow its replacement guidance.
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, so the evidence should be matched to the element rather than inferred from the stainless-steel vessel itself.
Phoenix Gravity Chloramine Test Results
Phoenix Gravity New Millennium Edition™ Filter Elements are the current primary replacement option for compatible Berkey® gravity-fed systems. In the April 20, 2026 Atom Testing Laboratory report, chloramine was reported at 3.02 mg/L before filtration and below 0.1 mg/L after filtration. Using the displayed reporting limit conservatively, that supports a reduction greater than 96.69% under the documented laboratory conditions.
This is independent laboratory testing, not a universal performance guarantee for all source-water conditions or service volumes. Review the complete context on the Phoenix Gravity Filter Test Results page.
Certification distinction: NSF currently lists Travel Berkey®, Big Berkey®, and Royal Berkey® configurations featuring Phoenix Gravity New Millennium Edition™ Filter Elements under NSF/ANSI 42 for chlorine reduction and taste-and-odor reduction. The current NSF listing does not identify chloramine reduction as a certified claim. Phoenix chloramine performance is documented separately through independent laboratory testing.
What About Black Berkey® Elements?
If you already have Black Berkey® Elements installed, evaluate chloramine performance using Black Berkey®-specific documentation rather than Phoenix test data. Standalone Black Berkey® replacement elements remain unavailable through normal authorized U.S. distribution channels, so customers who need compatible primary replacement elements should now review the Phoenix Gravity option.
Review Current Berkey® Filter Options
Compare the Phoenix laboratory results and current replacement options before choosing a configuration.
Choosing the Right Berkey® System Size
Once the filter element fits your water-quality goals, choose the system size based on 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 and current configurations, see our Berkey Water Filter Systems comparison guide. Travel, Big, and Royal are especially relevant when reviewing the current NSF-listed Phoenix-equipped configurations.
Chloramine and Disinfection Byproducts
One reason utilities may use chloramination is to help manage formation of certain regulated disinfection byproducts associated with free chlorine. Chloramination does not eliminate disinfection-byproduct considerations; utilities still balance disinfectant effectiveness, source-water chemistry, distribution conditions, and regulated byproduct formation.
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. Seasonal changes in source water, treatment adjustments, water temperature, and building plumbing can all affect taste.
If the change is strong, sudden, persistent, or accompanied by unusual color or sediment, contact your water utility rather than diagnosing the issue 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.
Is chloramine the same as chlorine?
No. Monochloramine is commonly formed by adding ammonia to chlorine under controlled treatment conditions. It is generally more persistent than free chlorine.
Can I remove chloramine by leaving water out overnight?
Not effectively in the way this method is sometimes used for free chlorine. Chloramine is considerably more stable.
Does activated carbon reduce chloramine?
Some carbon systems can reduce chloramine, but performance varies with media, contact time, flow rate, source-water conditions, and filter condition. Look for chloramine-specific data.
How can I find out whether my water contains chloramine?
Check your public water system's Consumer Confidence Report or contact the utility directly.
Do Phoenix Gravity filters reduce chloramine?
Independent April 2026 laboratory testing reported chloramine at 3.02 mg/L before filtration and below 0.1 mg/L after filtration, supporting a conservative reduction greater than 96.69% under the documented test conditions. This is separate from the current NSF/ANSI 42 Berkey® listings, which identify chlorine reduction and taste-and-odor reduction rather than chloramine reduction.
When should a chloramine filter be replaced?
Follow the rated-capacity or replacement guidance for the exact filter. Do not assume chloramine performance continues indefinitely beyond the product's intended service life.
Final Thoughts
Chloramine is an intentional part of drinking-water treatment in many communities. Its persistence is useful to water utilities but also means homeowners should not treat it exactly like free chlorine.
If your goal is reduction at the tap, first confirm what your utility uses and then choose a filter with documented performance for that exact disinfectant.
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.