Chloramine vs Chlorine: What’s The Difference?
Quick Summary: Chloramine, a chemical variant of chlorine containing ammonia, is increasingly replacing chlorine in municipal water treatment due to its longer-lasting disinfecting properties and reduced taste and odor. While chloramine is generally safe for drinking and household use, it can pose risks to specific populations, such as dialysis patients and those with respiratory issues, and is harmful to aquatic life. Municipalities favor chloramine for its effectiveness in ensuring long-term water disinfection and reduced buildup in water systems, although it can be more corrosive to pipes and impact baking outcomes.
Los Angeles tap water is treated before it reaches your home. That treatment includes disinfectants designed to kill bacteria and other pathogens as water travels through miles of pipes. For most of LA’s history, that disinfectant was chlorine. That’s been changing.
The LADWP is currently in the process of converting the entire city water system from chlorine to chloramine. If you’ve noticed a shift in how your tap water smells or tastes, or you’ve received a notice from your water district, this is likely why.
Here’s what both chemicals are, how they compare, and what it means for your water at home.
What Is Chlorine?
Chlorine is a chemical disinfectant that has been used to treat municipal drinking water since the early 1900s. It kills bacteria, viruses, and other pathogens effectively and quickly. Most people recognize it by its distinctive smell, similar to a swimming pool.
Chlorine is added to water at the treatment plant, but it breaks down relatively quickly as water travels through the distribution system. In a large, spread-out city like Los Angeles, that limited staying power is one of its drawbacks.
Los Angeles tap water currently measures chlorine at 1.9 mg/l, well below the EPA maximum contaminant level of 4.0 mg/l. The water meets federal standards, but chlorine at any level can affect taste, smell, and skin, and it reacts with organic matter in the water to form disinfection byproducts.
What Is Chloramine?
Chloramine is formed by combining chlorine with ammonia. It’s been used as a drinking water disinfectant in the US for more than 90 years and is approved by the EPA and the State of California.
The key difference between chloramine and chlorine is stability. Chloramine stays active in water longer, which makes it more effective at maintaining disinfection as water moves through long distribution systems. It also tends to produce a less noticeable smell and taste than chlorine.
Chloramine is the disinfectant used in water purchased from the Metropolitan Water District of Southern California, which supplies a significant portion of LA’s water. As LADWP works to blend more MWD water into the city’s supply, the shift toward chloramine treatment across the whole system has followed.
Does LA Use Chlorine or Chloramine?
Both, depending on where you live, and that’s shifting.
The harbor and eastern portions of Los Angeles have received chloraminated water for more than 25 years, since that water comes primarily from the MWD. Other parts of the city have historically used chlorine but are being converted.
LADWP is currently constructing chloramination facilities across the city as part of a system-wide conversion. Active projects include the 99th Street Water Treatment Plant in South LA, the North Hollywood Ammoniation Station, and the Mission Wells Chloramination Station in Sylmar, with construction running through 2027 and 2029 respectively.
Other cities in the LA area, including Burbank, Glendale, Pasadena, and the Crescenta Valley Water District, have also made the switch to chloramine in recent years, largely driven by the need to use more imported water, which is typically treated with chloramine.
If you’re unsure which disinfectant your local district uses, you can check your annual Consumer Confidence Report or call your water provider directly. Water districts are required by law to notify customers of any switch from chlorine to chloramine.
Chlorine vs Chloramine: How They Compare
| Effect | Chlorine | Chloramine |
|---|---|---|
| Chemical makeup | Chlorine only | Chlorine + ammonia |
| Staying power in pipes | Breaks down faster | Stays active longer |
| Taste and odor | More noticeable | Less noticeable |
| Disinfection byproducts | Higher (THMs, HAA5s) | Lower, but different byproducts |
| Pipe corrosion | Less corrosive | More corrosive over time |
| Safe for dialysis? | Must be removed | Must be removed |
| Safe for fish tanks? | Must be removed | Must be removed |
| Removable by boiling? | Yes | No |
| Removable by carbon filter? | Yes | Requires catalytic carbon |
Pros and Cons of Each
Chlorine advantages:
- Fast-acting disinfectant
- Easier to remove at home through boiling or standard carbon filtration
- Well-understood, widely used for over a century
Chlorine drawbacks:
- Breaks down faster in pipes, limiting effectiveness over long distances
- More noticeable taste and odor
- Reacts with organic matter to form trihalomethanes (THMs) and HAA5 disinfection byproducts at higher levels
Chloramine advantages:
- Stays active longer in the distribution system
- Produces fewer trihalomethane byproducts
- Less noticeable taste and odor in most cases
Chloramine drawbacks:
- More corrosive to pipes and rubber plumbing fixtures over time
- Cannot be removed by boiling or standard carbon filters
- Requires catalytic carbon for effective removal at home
- Harmful to dialysis patients if not removed from dialysis water
- Toxic to fish and aquatic animals
Health Effects: What to Know
For most people, drinking water treated with chloramine or chlorine at regulated levels does not cause harm. The EPA and CDC both state that water treated with either disinfectant at standard levels is safe to drink, cook with, and bathe in.
That said, there are specific groups who need to pay closer attention.
- Dialysis patients: Both chlorine and chloramine must be removed from water used in dialysis machines. Chloramine can enter the bloodstream during dialysis and interfere with red blood cells. Standard dialysis filters may only remove chlorine, not chloramine. If you or a family member is on dialysis, check with your dialysis provider to confirm your equipment handles chloramine.
- People with respiratory sensitivities: Chloramine vapors can accumulate in enclosed spaces like showers and small bathrooms. People with asthma or other respiratory conditions may notice increased irritation. Improving ventilation and using a whole-house filter can help.
- Skin and hair: Both chlorine and chloramine can dry out skin and hair with regular exposure through bathing and showering. Chloramine in particular may cause irritation for people with sensitive skin. A whole-house carbon filtration system reduces exposure at every tap and shower.
- Fish and aquatic animals: Both chlorine and chloramine are toxic to fish at typical tap water concentrations. Chlorine can be neutralized by letting water sit out or using a dechlorination product. Chloramine requires a specific dechlorination product that targets both the chlorine and ammonia components. If you have an aquarium, check that your treatment product is rated for chloramine, not just chlorine.
- Plants: Chloraminated water is generally safe for most household plants. Some sensitive species may be affected over time with regular watering. Using filtered or distilled water for sensitive plants is a straightforward solution.
How to Remove Chloramine from Your Water
This is where chloramine differs from chlorine in a meaningful way. Standard activated carbon filters reduce chlorine effectively but do not reliably remove chloramine.
To remove chloramine, you need one of the following:
Catalytic carbon filters: These are specifically designed to break down chloramine. Catalytic carbon has a higher surface activity than standard carbon and can handle the chloramine molecule more effectively. Whole-house catalytic carbon filters are the most common solution for homeowners who want chloramine removed at every tap.
Reverse osmosis systems: RO filtration reduces chloramine along with a wide range of other contaminants. An RO system installed under the kitchen sink gives you filtered water for drinking and cooking.
Combination systems: Some homeowners use a whole-house catalytic carbon filter paired with an RO system under the sink for drinking water. This addresses both whole-home exposure and point-of-use drinking water quality.
Note: Boiling water removes chlorine but does not remove chloramine. If your water has been switched to chloramine treatment, boiling is not an effective removal method.
How Do I Know If My Water Has Chloramine?
The clearest way is to check your annual Consumer Confidence Report, which your water district is required to publish each year. It lists the disinfectants used and their levels.
You can also call your water provider directly or check their website. If LADWP is your provider, their site includes information on the ongoing system-wide chloramine conversion.
A water test is the most complete option. It confirms what’s in your water and at what levels, which helps you decide whether a filter makes sense and what type would work best.
Chloramine in Tap Water FAQ
Is chloramine safe to drink?
Yes, at the levels used in municipal water treatment. The EPA and CDC consider chloraminated water safe for drinking, cooking, and bathing for most people. Specific groups, including dialysis patients, should take additional precautions.
Does chloramine affect the taste of water?
Chloramine generally has less of a noticeable taste and odor than chlorine. Some people are still sensitive to it. A carbon or catalytic carbon filter reduces both taste and odor from either disinfectant.
Can I remove chloramine by boiling water?
No. Boiling removes chlorine but does not remove chloramine. You need a catalytic carbon filter or reverse osmosis system to reduce chloramine in tap water.
Is chloramine safe for my fish tank?
No. Chloramine is toxic to fish and aquatic animals. Standard dechlorination products may only neutralize chlorine. Use a product specifically rated to remove both chlorine and ammonia (the two components of chloramine) before adding tap water to your aquarium.
Is chloramine safe for plants?
Most household plants tolerate chloraminated water without issue. Sensitive species may do better with filtered or distilled water over time.
What filter removes chloramine?
Catalytic activated carbon filters are the most effective option for removing chloramine. Standard carbon filters work well for chlorine but are less effective against chloramine. Reverse osmosis systems also reduce chloramine along with many other contaminants.
Free chlorine vs chloramine: what’s the difference?
Free chlorine refers to chlorine that hasn’t yet reacted with other compounds in the water. Chloramine is formed when chlorine combines with ammonia. Free chlorine is more reactive and breaks down faster. Chloramine is more stable and stays in the water longer.
How Culligan of Los Angeles Can Help
As LADWP continues its system-wide conversion to chloramine, more LA households will be dealing with water that standard filters aren’t built to handle. If you’ve noticed changes in your water’s taste or smell, or you’ve received a notice from your water district about a disinfectant switch, a water test is a practical first step.
Culligan of Los Angeles offers free water tests that can identify what’s in your water, including which disinfectants are present and at what levels. From there, a Culligan water specialist can walk you through which filtration option, whether a whole-house catalytic carbon system, an RO filter, or a combination, fits your home and your concerns.
If you’re not sure what’s coming through your tap, testing takes the guesswork out of it.
