Every filter on the shelf promises better water. Very few say a word about fluoride. If you’ve decided you want it out of your drinking water, the next question is which option does the job.
Reverse osmosis does. It removes most of the fluoride in tap water. Below, we cover how much it takes out, how it works, and what changes on city water versus a well.
Quick Answer: Does Reverse Osmosis Remove Fluoride?
Yes. A reverse osmosis (RO) system removes most of the fluoride in your water, whether it comes from a city line or a private well. According to the Water Quality Association, an industry group for water treatment, RO removes roughly 80 to 95 percent of fluoride, depending on the membrane.
How Reverse Osmosis Gets Fluoride Out of Your Water
An RO system pushes water through a membrane with extremely small openings. Water gets through. Fluoride dissolves in water as tiny charged particles, and the membrane holds back most of them, along with other dissolved minerals and salts. A stream of water rinses them away.
Most under-sink systems work in stages. Sediment and carbon filters go first and protect the membrane, and the membrane does the fluoride work. Many systems finish with one more carbon filter right before the faucet. The treated water collects in a small storage tank. RO makes water slowly, so the tank keeps a full glass ready when you turn on the tap.
Those carbon stages also cut chlorine taste and smell. If chlorine is on your list too, our guide on how to remove chlorine from tap water covers your options. According to the CDC, RO also removes metals such as lead and copper.
How Much Fluoride Does Reverse Osmosis Remove?
According to the Water Quality Association, cellulose membranes remove 80 to 90 percent of fluoride, and thin-film composite membranes remove up to 95 percent. Where your system lands in that range depends on the type of membrane, your water pressure, and how old the membrane is.
As a rough example, if your tap water is at 0.7 parts per million (ppm), the unit water reports use, and your system removes 90 percent, the water at your RO faucet comes out around 0.07 ppm. Membranes wear over time, so replacing the filters and membrane on schedule helps the system hold its removal rate.
City Water or Well Water: What Changes?
On city water, your utility sets the fluoride level, and both Jefferson City and Columbia add it on purpose. Jefferson City’s 2025 report shows a 0.7 ppm target and readings from 0.23 to 0.97 ppm. Columbia’s 2025 report lists 0.7 ppm. Utilities add fluoride to a set target, so your tap should sit close to those numbers. You can find your own number in your utility’s annual water quality report.
Wells work differently. Private wells fall outside the rules that cover city systems, so nobody checks your fluoride unless you do. Wells also get no added fluoride, so whatever is in yours comes from the ground. Some wells have almost none, and some carry natural fluoride in higher amounts. A free water test tells you which one you have. It also shows whatever else is in the water, like iron or hardness, which can change what setup makes sense.
What Installing an RO System Involves
Most home RO systems go under the kitchen sink, with a small faucet on the counter for the filtered water. The system ties into your cold water line and your drain, and installation typically takes one to two hours. RO works best at a water pressure of about 40 to 80 PSI, and an installer checks yours before setting one up. Plan on replacing the filters every six to 12 months and the membrane every two to three years, depending on your water usage and quality. Some models need no tools for filter swaps. Our guide on what to know before installing a reverse osmosis system covers the prep in more detail.
What to Ask Before You Buy an RO System
Four questions cover most of it. What type of membrane does the system use, since that sets the removal range above? How often do the filters and membrane need replacing, and who handles it? Does the system fit under your sink with room for the tank? Last, what does a water test say about your water? The answers show whether a system fits your home, and a good installer will walk you through all four.
Frequently Asked Questions
Does reverse osmosis remove all fluoride?
No system removes every bit. RO gets most of it, which is why the range runs from 80 to 95 percent instead of 100. The exact number depends on the membrane and your water.
Does reverse osmosis remove fluoride and chlorine?
Yes. The membrane handles fluoride, and the carbon filters that come with most RO systems handle chlorine taste and smell.
Does reverse osmosis work on well water?
Yes. RO removes fluoride from well water the same way it does from city water. Iron, hardness, or sediment in a well can call for extra treatment ahead of the RO system, and a water test shows which of those you have.
Does an under-sink RO system treat the whole house?
No. It treats one tap, the one you drink and cook from. Showers and laundry keep running on regular water.
Do pitcher and fridge filters remove fluoride?
Usually not. They typically use activated carbon, and the CDC says the main job of those filters is to improve taste and smell. Read the box, since a filter that reduces fluoride will say so.
Does a water softener remove fluoride?
No. Softeners are built to catch hardness minerals like calcium and magnesium, and fluoride passes right through.
Ready to Take Fluoride Out of Your Drinking Water?
Mid-Mo Water Solutions installs and services reverse osmosis systems that remove fluoride from your drinking water, for homes in Jefferson City, Columbia, Lake of the Ozarks, and the surrounding mid-Missouri communities. Contact Mid-Mo Water Solutions and we’ll help you choose a system that fits your home and your water.