If your tap water sometimes smells faintly like a swimming pool, the most likely explanation is residual disinfectant from municipal water treatment. Chlorine plays an important public-health role, but some households choose to reduce the residual chlorine in water used for drinking because they prefer the resulting taste and odor.
Why Is Chlorine Added to Drinking Water?
Disinfection is one of the most important steps in public water treatment. Chlorine is widely used because it can disinfect water during treatment and leave a residual that continues to protect water as it moves through storage tanks and distribution pipes.
The amount reaching a particular faucet can vary with utility operations, water demand, temperature, distance through the distribution system, and other conditions. A noticeable chlorine odor therefore does not necessarily mean the water is outside regulatory limits.
Why Does My Tap Water Suddenly Smell Like Chlorine?
A stronger-than-usual chlorine smell can have several explanations. Your utility may have adjusted treatment, distribution conditions may have changed, or you may simply be noticing the odor more strongly because of temperature or individual sensitivity.
If the change is sudden, unusually great, or persists, check your water utility's notices or contact the utility rather than assuming the cause. Utilities sometimes make operational changes or temporarily adjust disinfection practices.
EPA Chlorine Limits Explained
EPA regulates residual disinfectants under the Stage 1 Disinfectants and Disinfection Byproducts Rule.
| EPA value | Chlorine | Meaning |
|---|---|---|
| MRDLG | 4 mg/L as Cl₂ | Non-enforceable public-health goal for residual chlorine. |
| MRDL | 4.0 mg/L as Cl₂ | Enforceable maximum residual disinfectant level for applicable public water systems. |
For chlorine, compliance with the MRDL is based on the applicable system monitoring and averaging requirements, rather than treating 4.0 mg/L as a simple pass/fail reading for each glass of water. EPA rules also allow systems to raise residual disinfectant temporarily when necessary to address specific water-quality conditions.
Is Chlorinated Drinking Water a Health Concern?
Chlorination has major public health benefits because it controls waterborne diseases. EPA set the chlorine MRDL and MRDLG at 4 mg/L based on its health assessment while allowing utilities to maintain effective disinfection.
A separate issue is the formation of disinfection byproducts (DBPs) when disinfectants react with naturally occurring material in source water. EPA therefore regulates both disinfectant residuals and several DBPs, including total trihalomethanes (TTHMs) and haloacetic acids (HAA5).
These are different questions: the amount of residual chlorine at your tap is not the same measurement as the concentration of TTHMs or HAA5. If DBPs are your concern, review your utility's Consumer Confidence Report and see our TTHM Guide and HAA5 Guide.
Chlorine vs. Chloramine: Why the Difference Matters
Chlorine and chloramine are both used as drinking-water disinfectants, but they behave differently. Chloramines are most commonly formed when ammonia is added to chlorine. They are more stable and provide longer-lasting residual disinfection as water moves through distribution pipes.
| Characteristic | Chlorine | Chloramine |
|---|---|---|
| Role | Common primary and/or secondary disinfectant | Commonly used for longer-lasting secondary disinfection |
| Stability in distribution | Breaks down more readily | More stable and longer lasting |
| Taste/odor | Can be more noticeable to some people | Often less noticeable, though individual perception varies |
| EPA MRDL | 4.0 mg/L as Cl₂ | 4.0 mg/L as Cl₂ |
| Home treatment | Activated carbon can be effective | Requires filter performance specifically appropriate for chloramine; do not assume chlorine performance is equivalent |
If you do not know which disinfectant your utility uses, check its Consumer Confidence Report or contact the utility. For more detail, see Chloramine in Drinking Water.
Does Letting Water Sit Remove Chlorine?
Free chlorine can dissipate over time when water is exposed to air, so some people notice less chlorine odor after water sits. Temperature, surface area, starting concentration, and other conditions affect how quickly this happens.
This should not be treated as a precise treatment method, and it is much less useful for chloramine, which is more stable. If consistent reduction is important, use a filter with documented performance for the disinfectant your utility actually uses.
How Can Chlorine Be Reduced From Drinking Water?
For drinking and cooking water, several point-of-use approaches can reduce residual chlorine. Activated carbon is widely used because it reacts readily with chlorine. Options include pitchers, faucet filters, under-sink systems, and countertop gravity filters.
Whole-house carbon systems are another option when the goal is to reduce chlorine throughout the home, but they require different sizing, flow, maintenance, and installation considerations than drinking-water filters.
Can Berkey® Filters Reduce Chlorine?
Yes. Both Black Berkey® Elements and Phoenix Gravity New Millennium Edition™ Filter Elements have documented chlorine-reduction performance.
Black Berkey® Elements
Manufacturer-published independent laboratory testing for Black Berkey® Elements includes chlorine reduction. Existing owners using Black Berkey® Elements can review the Black-specific reports on our Berkey® Filter Test Results page.
Phoenix Gravity New Millennium Edition™
Phoenix Gravity PGF9-2 has an additional advantage for this particular contaminant: the filter element itself is currently listed by NSF under NSF/ANSI 42 in the filter-cartridge component category for chlorine reduction and taste-and-odor reduction. NSF notes testing to a capacity of 4,000 liters for those NSF/ANSI 42 claims.
Separately, Travel Berkey®, Big Berkey®, and Royal Berkey® system configurations featuring Phoenix Gravity elements are currently listed under NSF/ANSI 42 for chlorine reduction and taste-and-odor reduction, with a listed service cycle of approximately 1,050 gallons.
What About Chloramine?
Phoenix also has independent laboratory evidence for chloramine reduction: April 2026 testing reported chloramines at 3.02 mg/L before filtration and <0.1 mg/L after filtration, corresponding to a calculated reduction greater than 96.69% under the documented conditions. That chloramine result is independent laboratory evidence; it is not an NSF chloramine-reduction certification.
Review the full test evidence and current replacement-filter options for the exact element installed in your system.
Choosing a Berkey® System Size
The stainless-steel system determines water-storage capacity; chlorine-reduction performance depends on the filter element installed.
| System | Capacity | Typical Fit | Product |
|---|---|---|---|
| Travel Berkey® | 1.5 gallons | Singles and couples | View Travel Berkey® |
| Big Berkey® | 2.25 gallons | Many households | View Big Berkey® |
| Royal Berkey® | 3.25 gallons | Larger households | View Royal Berkey® |
| Imperial Berkey® | 4.5 gallons | Higher daily use | View Imperial Berkey® |
| Crown Berkey™ | 6 gallons | Large households and group use | View Crown Berkey™ |
Frequently Asked Questions
Why does my tap water sometimes smell more strongly of chlorine?
Utility treatment changes, distribution conditions, temperature, and individual sensitivity can all affect how noticeable chlorine seems. If the change is sudden or unusually strong, check utility notices or contact your water provider.
What is EPA's limit for chlorine in drinking water?
EPA's MRDL for chlorine is 4.0 mg/L as Cl₂, and the MRDLG is 4 mg/L. These values apply within EPA's regulatory framework for residual disinfectants in public water systems.
Is chlorine the same as chloramine?
No. Chloramine is most commonly formed by adding ammonia to chlorine and is more stable in distribution systems. A filter's chlorine performance should not automatically be assumed to apply to chloramine.
Does refrigerating or letting tap water sit remove chlorine?
Free chlorine can dissipate when water is exposed to air, so its odor may decrease over time. Results vary, and this approach is much less effective for chloramine because chloramine is more stable.
Do Black Berkey® Elements reduce chlorine?
Yes. Black Berkey® Elements have independent laboratory evidence for chlorine reduction. Review the Black-specific reports on the Berkey® Filter Test Results page for the documented conditions.
Are Phoenix Gravity elements NSF listed for chlorine reduction?
Yes. Phoenix Gravity PGF9-2 is currently listed by NSF under NSF/ANSI 42 in the filter-cartridge component category for chlorine reduction and taste-and-odor reduction. NSF notes testing to 4,000 liters for those claims.
Do Phoenix Gravity elements reduce chloramine?
Independent April 2026 testing reported chloramines at 3.02 mg/L before filtration and below 0.1 mg/L after filtration, or greater than 96.69% calculated reduction under the documented conditions. This is independent testing, not an NSF chloramine-reduction certification.
Related Drinking Water Guides
Final Thoughts
Chlorine in municipal tap water is there for an important reason: maintaining disinfection from the treatment plant through the distribution system. A noticeable chlorine taste or odor does not by itself mean the water is outside EPA requirements.
If you prefer less residual chlorine in drinking water, first determine whether your utility uses chlorine or chloramine. Then choose a treatment option with documentation for that disinfectant. Both Black Berkey® and Phoenix Gravity elements have evidence of chlorine reduction, while Phoenix PGF9-2 also has a current NSF/ANSI 42 component listing for chlorine and taste-and-odor reduction.