It’s no secret that reverse osmosis is a top-tier option for cleaning up your drinking water — but can it handle chlorine?
The short answer: yes, but not on its own.
RO systems rely on a combination of pre-filters and a semi-permeable membrane to remove contaminants. While the membrane is excellent at filtering out heavy metals, dissolved solids, and other microscopic threats, chlorine can damage it over time. That’s why these systems come equipped with carbon filters up front — to handle chlorine before it ever reaches the membrane.
In this guide, we’ll break down how they work, how it deals with chlorine specifically, and what to look for if chlorine is your top concern.
Key Takeaways:
- 💧 RO systems can remove chlorine — but only with the help of carbon pre-filters.
- 🧪 Chlorine can damage RO membranes, so it needs to be filtered out first.
- 🔍 Most RO systems include activated carbon filters to handle chlorine and chloramine.
- 🚿 If your water smells or tastes like chlorine, make sure your RO system includes the right filters.
- 🧰 For maximum effectiveness, look for systems with NSF-certified carbon filtration stages.
⚠️ What Are the Health Risks?
Chlorine does a pretty decent job at disinfecting water, but prolonged exposure — especially through drinking — can raise a few concerns for sensitive individuals. Here are some of the possible side effects and why some people prefer to reduce it in their water:
- Dry skin & irritation – Showering in chlorinated water may leave your skin feeling dry or itchy.
- Eye discomfort – Some people report stinging or redness, especially with higher levels.
- Respiratory sensitivity – Chlorine vapor may trigger issues in those with asthma or allergies.
- Unpleasant taste or smell – That pool-like flavor isn’t dangerous, but it’s not exactly refreshing.
- Byproducts like THMs – Long-term exposure to chlorine byproducts (like trihalomethanes) has been loosely linked to potential risks involving the liver, kidneys, and nervous system.
For most people, the levels in treated tap water are considered safe. But if you’re aiming to reduce exposure — especially for children or vulnerable family members — filtering chlorine out can offer some peace of mind.
How Does Reverse Osmosis Work?
If biology wasn’t your strong subject, remember that osmosis is the tendency for molecules to move from areas of higher concentration to areas of lower concentration.
RO filtration systems reverse osmotic pressure, forcing water through a semi-permeable membrane with very tiny pores that eliminate all dissolved solids larger than water molecules.
If you use city water, incoming water pressure is usually enough to power the process. But if you have a well that delivers less than 50 psi, you’ll need a system equipped with an electric or a non-electric permeate pump.
💧 How Is Chlorine Removed from Tap Water?
Chlorine is a strong disinfectant, but it’s also relatively easy to remove — if you’re using the right technology.
Most standard filters, like those in pitchers or faucet attachments, use activated carbon. It works really well at improving taste in smell by capturing the chlorine molecules as the water passes through.
But when it comes to more advanced systems (like reverse osmosis), the removal process is actually a two-step approach:
- Carbon Prefiltration – Before water reaches the RO membrane, it flows through a carbon filter. This step removes most of the chlorine — which is important because chlorine can degrade the RO membrane over time.
- Membrane Filtration – After the chlorine is taken care of, the membrane filters out smaller contaminants like lead, nitrates, and even fluoride.
While RO systems aren’t technically “chlorine filters,” they do remove it — just not all on their own. The carbon filter does the heavy lifting upfront.
💡 Bonus: Most R.O’s also remove other common contaminants like lead, fluoride, arsenic, and PFAS — giving you broad protection beyond chlorine.
💧 Why Pre-Filters Matter in RO Systems
Reverse osmosis membranes can’t handle chlorine directly — it damages the membrane. That’s why RO systems include pre-filters made from activated or catalytic carbon. These filters remove chlorine first, so the membrane can do its job filtering everything else.
⚗️ Chlorine vs. Chloramine – Why It Matters
Not all disinfectants are created equal.
Many public water systems have shifted from chlorine to chloramine, a compound made by combining chlorine with ammonia. Why the switch? Chloramine sticks around longer in the distribution system, offering extended protection against bacteria.
But here’s the catch:
💡 Chloramine is harder to remove. Standard carbon filters struggle with it, and unlike chlorine, it doesn’t evaporate from water left to sit on the counter.
So where does RO fit in?
While the membrane itself doesn’t filter chloramine directly, systems with high-quality catalytic carbon filters in the pre-treatment stage can effectively break it down before it ever touches the membrane. This is an important upgrade to look for if you know your water supply contains chloramine instead of chlorine.
Bottom line: If your city uses chloramine, not just any filter will do — make sure your system is equipped to handle it.
🛠️ Types of Reverse Osmosis Systems
Not all RO systems are built the same. Here’s a quick look at the most common types and how they differ:
- Whole House RO Systems – These treat every drop of water entering your home. They’re powerful but expensive — usually reserved for situations with very high contamination levels or unique water quality issues.
- Under Sink Systems – Installed beneath your kitchen sink, these are the most popular type for households. They typically include multiple stages of filtration, including carbon pre-filters to remove chlorine.
- Countertop Units – A great option for renters or smaller households. These plug into your faucet and don’t require installation — just set them up and go.
- Tankless Systems – Sleek and space-saving, these newer models filter water on demand without a storage tank. They’re often faster and take up less room, but may come at a higher price point.
💡 Thinking About RO? Here’s the Trade-Off
It’s one of the most thorough water treatment methods available — but like any system, it comes with upsides and downsides. Here’s a quick breakdown to help you decide if it’s the right fit for your home:
| 👍 Pros | 👎 Cons |
|---|---|
| Removes chlorine, lead, PFAS, and dozens of other contaminants | Wastes water during filtration (about 2–4 gallons per 1 gallon filtered) |
| Improves taste, smell, and clarity of drinking water | Removes beneficial minerals (like calcium and magnesium) |
| Great for people with sensitivities to chemical additives | May require re-mineralization for better taste or balance |
| Under-sink systems are compact and easy to install | Filters need periodic replacement (typically every 6–12 months) |
| Tankless systems save space and filter on demand | Higher upfront cost compared to basic filters |
🔍 Bottom Line: If you’re concerned about a wide range of water contaminants — including chlorine — RO’s offers peace of mind. Just be aware of the maintenance and water use so you can weigh value vs. cost.
💧 Where Reverse Osmosis Works Best
These systems shine when water quality really matters. They’re ideal for:
☕ Coffee & Tea Lovers – Reduces off-flavors that come from chlorine or hard minerals — better water means better brew.
🥤 Drinking & Cooking – Delivers crisp, clean water right from the tap.
👶 Baby Formula – Removes chlorine, fluoride, and other chemicals not suited for sensitive systems.
🧪 Home Testing or Labs – Produces low-mineral, high-purity water that’s perfect for experiments and aquariums.
🏡 Homes with Well Water – When paired with pre-treatment (like sediment or carbon filters), RO systems help safeguard against common well contaminants like nitrates, arsenic, and bacteria.
Have a look at our top list. of RO systems.
Final Thoughts
Chlorine is a modern miracle with a dark side. But you can have your cake and eat it too by filtering it out of your water once it’s done its job with a reversal osmosis filter.
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