What’s flowing from your tap might seem clean, but there’s a good chance it’s been chemically treated, and not all disinfectants are created equal.
For over a century, cities across the U.S. have used chlorine in drinking water to eliminate harmful water contaminants like bacteria. More recently, many have made the switch to chloramine – a combination of chlorine and ammonia that sticks around longer in the system.
Both do their job. But both also raise questions about long-term exposure, potential health effects, and how to filter them out at home.
If you’re wondering what your family is actually consuming, you’re not alone. At Leaf Home, we believe clean water shouldn’t be a mystery. So we’re breaking down how water gets treated, and how you can check exactly what’s in your city’s supply.
In this article:
- Understanding Water Disinfection
- Health and Safety Considerations
- Disinfection Practices Across U.S. Cities
- Managing Disinfectants in Your Home
- Your Water, Your Choice: What Every Homeowner Should Know
- Frequently Asked Questions
Understanding Water Disinfection
Before water reaches your faucet, it’s treated to remove dangerous bacteria, viruses, and parasites. Municipal public water systems rely on chemical disinfectants to make this possible, but the type of chemical used can affect everything from your health to how your tap water tastes.
The Importance of Disinfecting Drinking Water
Water disinfection is one of the most important public health advances of the last century. Without it, harmful pathogens like E. coli, Giardia, and norovirus could spread quickly through the water supply, putting entire communities at risk. Disinfectants neutralize these threats before they ever reach your home.
Chlorine vs. Chloramine: What’s the Difference?
The U.S. began disinfecting drinking water with chlorine as early as 1908, marking a major turning point in the control of waterborne illness. By 1929, chloramine was introduced as an alternative. Today, both methods are still widely used, but each comes with different advantages and concerns.
While both chlorine and chloramine are used to kill microbes in water, they differ in how they work and what they leave behind.
- Chlorine (Cl₂) is a powerful disinfectant that works quickly and effectively, but it can dissipate before reaching the far ends of the water system.
- Chloramine (NH₂Cl) is more stable, allowing it to linger in water longer, offering ongoing protection.
This difference in stability also affects how each one tastes and smells. Chlorine is often described as giving water a “pool-like” odor, while chloramine tends to be less noticeable. However, chloramine can react differently with other compounds in water, leading to its own set of chemical byproducts. More on this below.
Health and Safety Considerations
Disinfectants like chlorine and chloramine are essential for keeping drinking water safe, but that doesn’t mean they come without tradeoffs. Even small amounts can leave behind byproducts that raise questions about long-term health effects, especially for families with unique health concerns. Let’s take a closer look at what the science and safety standards say.
Regulatory Standards and Health Impacts
The Environmental Protection Agency (EPA) sets a strict limit on how much disinfectant can be in your tap water. For both chlorine and chloramine, the maximum allowed is 4.0 milligrams per liter (mg/L) – a level considered safe for the general population.
Your city’s water is tested regularly to make sure it stays below that limit. Still, there’s increasing concern about what happens when disinfectants react with organic materials in the water. These reactions can create disinfection byproducts, which may pose health risks over time, even when the original disinfectant levels fall within EPA guidelines.
If your city uses chlorine:
When chlorine interacts with naturally occurring materials in water, it can create compounds called trihalomethanes (THMs) and haloacetic acids (HAAs). These are known as disinfection byproducts, and they’re linked to potential health concerns like bladder cancer and issues affecting the liver and kidneys. Because of these risks, THMs and HAAs are federally regulated and closely monitored by water utilities.
If your city uses chloramine:
Chloramine creates a different group of byproducts, including N-nitrosodimethylamine (NDMA) – a probable human carcinogen, according to the EPA – and chloronitramide anion, a compound still being studied. NDMA can form in trace amounts during treatment and is currently unregulated, though researchers are watching it closely due to its toxicity even at very low levels.
Who Should Be Cautious with Water Disinfection
While chlorine and chloramine are safe for most people at regulated levels, certain groups may need to take extra precautions:
- Dialysis patients: Chloramine must be removed from water before it enters a dialysis machine, since standard medical filters don’t remove it.
- People with asthma or other respiratory sensitivities: Disinfectants can vaporize in hot water and irritate the lungs, especially during showers or dishwashing.
- Aquarium and pond owners: Chloramine is toxic to fish and amphibians, even in very small amounts. Unlike chlorine, it doesn’t go away on its own through boiling or letting the water sit. Aquarium water must be treated with neutralizers or conditioners made specifically to break down chloramine before it’s safe for aquatic life.
- Homebrewers: Both chlorine and chloramine can interfere with yeast activity during fermentation. This can affect the taste and quality of beer or kombucha. Chlorine can usually be removed by boiling or letting the water sit, but chloramine requires Campden tablets (potassium metabisulfite) or filtration with catalytic carbon to neutralize it completely.
These disinfectants play an important role in public health, but it’s still a good idea to understand how they affect your household. When you know what’s in your water, it’s easier to take steps that protect your health, your hobbies, and the people and pets that you care about.
Disinfection Practices Across U.S. Cities
Not all tap water is treated the same way. While every city aims to deliver clean, safe drinking water, the method used to disinfect it can vary depending on local infrastructure, cost, and public health goals. Understanding what your city uses is a simple step that can help you choose the right filtration system and feel more confident about the water coming into your home.
Major Cities Utilizing Chlorine
Many large cities, including New York City, Chicago, and Atlanta, continue to rely on chlorine as their primary disinfectant. Chlorine has been widely used for decades because it is both affordable and fast-acting. It begins killing bacteria and viruses almost immediately.
Chlorine is often a better fit for systems with shorter water distribution networks or older infrastructure. Because it doesn’t last as long in the water, some municipalities apply it closer to the point of delivery or combine it with other treatment methods to keep protection consistent.
Major Cities Utilizing Chloramine
Other cities have made the switch to chloramine, especially in places where the water needs to travel longer distances. Cities like Los Angeles, Boston, Philadelphia, and Tampa use chloramine because it stays active in the system longer, helping ensure protection from the treatment plant all the way to your faucet.
Chloramine is also linked to fewer regulated byproducts, such as THMs and HAAs. Although it works more slowly than chlorine, its stability makes it a smart choice for cities with sprawling water networks or warmer climates where residual disinfection needs to last.
How to Find Out What Your City Uses
If you’re not sure how your tap water is treated, it’s easy to find out. Here are the simplest ways to check your city’s disinfection method:
- Search your address at MyTapWater.org: This independent resource offers detailed breakdowns of water quality reports for many U.S. utilities.
- Use the EWG Tap Water Database: Enter your ZIP code to see what contaminants have been detected in your local supply, plus how your city treats it.
- Check the EPA’s Local Drinking Water Information page: This tool links to state-by-state water quality data and local contact info.
- Look at your annual Consumer Confidence Report (CCR): Most water utilities mail this each year, but you can also find it on your provider’s website.
- Call your local utility: Still not sure? Just ask. Public works or customer service can usually confirm which disinfectant – chloramine or chlorine – your system uses.
Knowing your state water quality and disinfection method can help you choose the right filter, avoid unnecessary exposure, and get the full benefits of filtered water at home.
Managing Disinfectants in Your Home
Even when your city stays within EPA guidelines, many homeowners still prefer to reduce or remove disinfectants from their drinking water. Whether you’re concerned about taste, health byproducts, or specific household needs, the right filtration system can make all the difference.
Filtration Options
Choosing the best filter starts with knowing what you’re trying to remove. And not all systems are equally effective against chlorine and chloramine:
- Activated Carbon Filters: These are among the most common filters found in pitchers and faucet attachments. They work well to reduce chlorine, improving both taste and odor, but are not effective against chloramine.
- Catalytic Carbon Filters: For homes with chloramine-treated water, catalytic carbon is also a great choice. This advanced form of carbon has been chemically enhanced to break the chlorine-ammonia bond in chloramine, effectively removing it. These are typically found in higher-end whole-house filtration systems.
- Reverse Osmosis (RO) Systems: These offer the most thorough level of filtration, using a multi-stage process to remove a wide range of contaminants, including chlorine, chloramine, heavy metals, PFAS, fluoride, and other impurities. While they tend to cost more and often require professional installation, they’re ideal for households seeking comprehensive water purification.
No matter which option you choose, make sure your system matches your local water treatment method. For chloramine-heavy areas, paired solutions like RO and catalytic carbon offer broader coverage and help you get the full benefits of filtered water, including better taste, fewer byproducts, and added peace of mind.
Your Water, Your Choice: What Every Homeowner Should Know
Chlorine and chloramine are both widely used to make drinking water safe, but each comes with different trade-offs. Chlorine acts fast but fades quickly, while chloramine sticks around longer and produces different chemical byproducts. Understanding which disinfectant your city uses can help you make more informed decisions about your water and the filtration options that best suit your household.
From health impacts to homebrewing concerns, knowing what’s in your water is the first step toward better protection. Whether it’s reading your local water report, investing in the right filter, or simply wanting a cleaner glass from the faucet, you don’t have to figure it out alone. With the right tools and knowledge, cleaner, safer water is well within reach.
Learn more about how you can get a free water test from our experts at Leaf Home Water Solutions.
Frequently Asked Questions
Is it safe to drink water treated with chloramine?
Yes. Chloramine-treated water is considered safe to drink under current EPA guidelines, which limit residual disinfectant levels to 4.0 mg/L. However, chloramine can cause skin, eye, or respiratory irritation in some people, especially at higher concentrations. Chloramine must be removed for specific uses, such as dialysis and aquariums, where it can be harmful even in trace amounts. That’s why knowing your water treatment method, and using appropriate filtration, is essential.
Do standard water filters remove chloramine?
No, not all filters remove chloramine. Basic activated carbon filters (like those in pitcher systems) are effective at reducing chlorine but not strong enough to break down chloramine. To remove chloramine effectively, you’ll need either a catalytic carbon filter or a reverse osmosis (RO) system that includes a catalytic carbon stage before the membrane. This pre-filtration step helps break the chlorine-ammonia bond so the RO membrane can do its job. Always check the filter’s specifications to make sure it’s rated for chloramine removal.
Why do some cities switch between chlorine and chloramine?
Cities may switch based on infrastructure needs, public health goals, or regulatory compliance. Chloramine is more chemically stable, making it better for cities with longer distribution systems. It also produces fewer regulated byproducts like THMs and HAAs. However, some municipalities still prefer chlorine for its cost-effectiveness and faster disinfection during treatment.
Do some cities switch disinfectants seasonally?
Some cities also switch seasonally: temporarily using chlorine for a few weeks each year to flush the distribution system and clean out biofilm or sediment. According to the North Texas Municipal Water District, nearly 40% of U.S. water providers that use chloramine make this kind of temporary switch annually. It’s a common and EPA-recognized maintenance practice designed to keep water quality high.
