More than 60 percent of public water supplies in the US contain added fluoride to prevent tooth decay. Proven effective, it’s nonetheless controversial as new research links excess fluoride consumption to health problems.
If you’d rather not take your chances, you can remove fluoride with a reverse osmosis filter. But RO technology can be as confusing as the fluoride issue.
If you’re wondering what’s a semi-permeable membrane, and how does reverse osmosis remove fluoride in water, keep reading. We’ll get to the bottom of that and more.
Key Takeaways:
- Yes, reverse osmosis systems are effective at removing fluoride from water.
- Reverse osmosis systems contain a semi-permeable membrane that helps to remove impurities and contaminants like fluoride.
- The process of reverse osmosis works by pushing water through the membrane and trapping the contaminants on one side while allowing only clean and pure water to pass through to the other side.
What Is Fluoride?
Fluoride is a naturally occurring element. How much of it is in groundwater depends on the concentration of fluoride in the surrounding rock. Some level of fluoride is found in nearly all water supplies — even ocean water contains 1 part per million (ppm).
The types of fluoride added to tap water to prevent dental cavities, however — sodium fluoride, sodium fluorosilicate and fluorosilicate acid — aren’t the same as the natural calcium fluoride found in soil. Yet once they’re dissolved, the result is the same — fluoride ions in your drinking water.
Fluoride in Drinking Water: The Controversy
Few health issues generate as much debate as adding fluoride to the municipal water supply. Experts on both sides have their opinions.
The WHO and the American Dental Association endorse drinking fluoridated water to improve dental health, saying it’s safe for human consumption. But agencies differ on how much fluoride should be added.
The US Department of Health and Human Services recommends maximum fluoride levels of 0.7 mg/L to mitigate health risks, such as dental fluorosis —an irreversible white tooth discoloration. The EPA, however, permits up to 4.0 mg/L.
So, while there’s a mountain of irrefutable evidence showing that added fluoride fortifies tooth enamel and reduces dental cavities by up to 40 percent in children, balancing the risk of dental fluorosis versus the benefit of less tooth decay is largely left up to consumers.
With the availability of fluoride toothpaste and topical fluoride treatments offered by dentists, many are wondering if adding fluoride to our drinking water supply is still safe. Limited studies link high fluoride intake to health issues from hypothyroidism to kidney disease.
If you’re on the fence, drinking filtered water is the obvious solution.
Do Reverse Osmosis Filters Remove Fluoride from Water?
Fluoride is a stubborn contaminant. The types added to municipal drinking water are salts that dissolve readily in water and are hard to filter. It’s the same struggle we have removing salt from seawater.
The ordinary activated carbon filters in refrigerators and filtration pitchers don’t remove excess fluoride. You need a special type of filter.
Reverse osmosis water purification systems are among the few that not only remove fluoride molecules, but they also reduce most other common contaminants.
How Much Fluoride Do Reverse Osmosis Systems Remove?
The reverse osmosis filtration process eliminates 90-95 percent of fluoride plus other contaminants. If your goal is fluoride-free water, some multi-stage RO systems also include an activated alumina filter to further improve fluoride removal rates.
How Does Reverse Osmosis Remove Fluoride?
A reverse osmosis filter forces water through a semi-permeable membrane with tiny pores that remove most contaminants larger than water molecules. Pure water is collected in a storage tank while contaminants go down the drain.
Pros and Cons of Reverse Osmosis Systems
Reverse osmosis filters remove fluoride and more, but like most filtration systems, they have pros and cons.
Pros:
Reverse Osmosis Systems Remove a Broad Range of Contaminants
RO water filters reduce fluoride, dissolved minerals, heavy metals and more. It’s the same technology water treatment plants use.
The only substances an RO filter doesn’t readily remove are chemicals. That’s why most systems are equipped with a carbon prefilter. Together, they reduce fluoride and most other contaminants including:
- Chlorine
- Pesticides
- Herbicides
- Drug residue
- Industrial chemicals
- VOCs
- Bacteria, parasites and more
A multi-stage RO system produces virtually pure drinking water.
An RO System Is Easy to Install
Installing a whole-house filter requires cutting into the main water line. If you’re handy, you can do it. But if you don’t know which is the business end of a ratchet, you’re better off hiring a pro, and that can double the cost of the project.
A countertop or undersink RO system can be installed in under an hour with no special tools or plumbing expertise.
RO Water Filters are Apartment-Friendly
Unlike whole-home water filters, RO systems require no permanent changes to the plumbing system. Compact, they connect to the kitchen faucet or the cold water line under the sink and can be easily disassembled. An RO water filter is an investment, so if you move often, why not take it with you?
Cons
A Reverse Osmosis System Can Reduce Water Pressure
An RO system dispenses drinking water from a storage tank. The internal pressure is limited, resulting in slower-than-average water flow from the tap.
They Require a Special Faucet
RO filters are not compatible with most kitchen faucets. Instead, they come with special air-gap dispensers that keep contaminated backflow from the plumbing system out of the storage tank. Some people don’t like the aesthetics, and the faucets can be tricky to install if you don’t have a third hole predrilled in your sink.
But they protect the integrity of your tap water supply. Even in a power outage, you can safely use the contents of the storage tank.
RO Filters Have Limited Capacity
Whole-house filtration systems treat your home’s entire water supply. Every drop is clean no matter which faucet or showerhead it comes from. But most RO units are undersink filters that treat water for drinking and cooking. Storages tanks hold just 3-5 gallons at a time.
The reverse osmosis process is slow, so most systems can only purify a maximum of 25-75 gallons per day. That’s plenty for most households, but a large family could run dry.
Whole-home reverse osmosis filters that produce water on demand are available but are cost-prohibitive at $3500 and up. Tankless systems are competitively priced, but the technology is still shaky.
Maintaining a Reverse Osmosis System Costs More
Conventional carbon filters cost a few dollars in bulk, but a reverse osmosis membrane can set you back $100 or more. They last longer — 1-3 years on average — but when maintenance time comes, the bill can hurt.
Reverse Osmosis Water Filters Waste Water
Reverse osmosis works by applying pressure to an RO membrane. Like spraying a garden hose against a wall, you can’t catch all the spray in a tiny bucket because the pressure is too high.
Similarly, a reverse osmosis system sends 1-3 gallons of fresh water down the drain for every gallon of purified water it makes. The wastewater can be repurposed, but it’s a hassle most people don’t want.
And Most Require a Booster Pump to Operate
Most wells don’t produce enough water pressure to power a reverse osmosis system without a booster pump. City water users fare better, but unless incoming pressure is at least 60 PSI, you’ll need an electric or permeate pump.
Electric pumps add to your utility bill. Permeate pumps don’t, but they’re somewhat less effective. Both make noise while operating.
Top FAQ’s
RO systems strip healthy minerals from water. Without calcium, magnesium and potassium, tap water lacks dimension.
Some customers report their drinking water tastes better because it has fewer contaminants. For others, the off taste persists. But flavor is subjective, and most people say they get used to the change quickly.
Whole-house filters that remove fluoride as effectively as RO filtration system can cost $1500 or more plus the price of installation. Undersink reverse osmosis filters are more affordable, starting at $200.
The only alternatives to an RO system for removing fluoride are activated alumina and bone char filters. Alumina removes fluoride, arsenic and hydrogen sulfide but little else. Bone char filters remove contaminants from arsenic to thallium but less fluoride.
If you have excess fluoride and other contaminants in your drinking water, you can’t beat a reverse osmosis water filter for the price. Despite its drawbacks, few filters excel at removing contaminants like an RO system.
Final Thoughts
Don’t lose sleep over fluoride in your water. A high-efficiency RO membrane eliminates large quantities of fluoride plus other toxins that make your tap water taste bad and can affect your health. Cheaper and more ecologically sustainable than buying bottled water, reverse osmosis is among the best solutions to water fluoridation.
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