Richard Arconti 
Are you concerned about PFAS in your water supply? If that’s the case, you’re likely worried about its effects on you and your family’s health. Hence, you might be considering using reverse osmosis as an in-home filter solution. This begs the question, how does reverse osmosis remove PFAS? And is it an effective PFAS treatment?
The EPA has come out with data showing that negative health effects can come from PFAS exposure levels much lower than initially thought! In some cases, you should not be exposed to any level of PFAS for certain negative health effects [1].
In this article, let’s learn more about reverse osmosis and discover how it can help treat forever chemicals in your drinking water. Let’s dive in!
What Exactly Is PFAS In Drinking Water
PFAS are useful in producing oil, stain, water, and heat-resistant products since they are stable and don’t significantly interact with other chemicals. The source of PFAS comes from your non-stick cookware, cosmetic products, water-repellent garments, stain-resistant fabrics and carpets, fire extinguishers, and fast food containers. PFAS have also received a lot of attention for their use in firefighting foam.
Also known as the “Forever Chemicals,” PFAS (Perfluoroalkyl and Polyfluoroalkyl Substances) is a family of 4,700 persistent man-made chemicals that are not naturally occurring in nature. In other words, these are indestructible chemicals that are virtually non-degradable, accumulating in the environment and the human body.
The most common class of PFAS is the PFOA (Perfluorooctanoic Acid) and PFOS (Perfluorooctane Sulfonate). PFOA and PFOS degrade exceedingly slowly in the environment, posing potential health and environmental hazards.
How Does PFAS Get Into The Water Supply?
PFAS are released into the environment at locations where they are manufactured, used, discarded, or spilled [2]. They can be transported by rainwater run-off into different surface waters, seep through the soil, and move into underground drinking water sources. Local water utilities are still learning about the presence of PFAS in drinking water and effective treatment remains limited. This is why having an in-home filtration system is critical for healthy tap water.
Acceptable PFAS Amounts In Water
To protect the citizens against the potential long-term health impacts from specific PFAS exposure in drinking water, the EPA’s lifetime health advisory levels, expressed in parts per trillion (ppt), indicated that PFOS levels should not exceed 0.02 ppt and 0.004 ppt for PFOA. This practically means you should not have any exposure to PFAS and the EPA has issued a Drinking Water Health Advisory accordingly.
Related Article: Best Reverse Osmosis Systems For PFAS
How Does Reverse Osmosis Remove PFAS?
Reverse Osmosis (RO) is a type of water treatment process that eliminates impurities (ions, chemicals, and micro-sediment) from water by applying pressure to drive water molecules through a semipermeable membrane. After this treatment, you’ll be left with pure, drinking water free of contaminants.
RO method is excellent for getting rid of PFAS. More than 90% of PFAS, both long- and short-chain forms, can potentially be removed from the feedwater.
To remove PFAS from drinking water, reverse osmosis depends on the permeability of the membrane surfaces. The holes of the membrane surface should ideally be 0.0001 microns.
Note that PFAS molecules are around 2 nanometers (or 0.002 microns) in size. Compared to the pores in a RO membrane, this is 10x larger than the RO membrane. So when the water is pumped through the membrane, it filters out the larger fluorinated molecules, and only water passes through the membrane. Thus, it leaves you with treated water.
The great perk about RO systems, they constantly reuse the water that has already passed through the membrane! The waste is thus reduced to a significantly lesser volume, approximately 20% of the volume of the raw water.
Over time, PFAS and other compounds removed during the filtration process become highly concentrated in the waste, resulting in a concentrated solution known as brine.
What Other Contaminants Are Removed During The Reverse Osmosis Process?
Reverse osmosis eliminates a lot of different contaminants aside from PFAS. Compounds gotten rid of by RO include: arsenic, chlorine, fluoride, heavy metals, lead, mercury, nitrates, bacteria, pesticides, pharmaceuticals, and sulfates
How To Test For PFAS In Water At Home
Knowing if you have PFAS, PFOS, or PFOA in your tap water can be confusing. Even large water treatment plants are still grappling with the problem. Fortunately, there are a number of resources you can use at home to detect the presence of forever chemicals in your drinking water.
Conduct A Home Water Test
Using a quality home water test kit is an effective method. Our favorite lab test kit from Tap Score is the most accurate way to test for PFAS in water at home. This water test kit has everything you need to take a representative sample of your tap water and send it off to an accredited lab for analysis. They will provide you with the results that include a complete, quantitative examination of typical PFAS chemicals down to amounts of less than 2 parts per trillion (PPT).
Check Environmental Working Group (EWG) Database
EWG’s database provides a free comprehensive analysis of tap water quality. Users may look up their water provider by ZIP code, view a list of contaminants in their water, and see how those levels compare to state and national averages and health guidelines.
Look at Consumer Confidence Reports (CCR) For Local Water Tests
There is a lot of information regarding the quality of your drinking water that can be found in Consumer Confidence Reports (CCRs). It also refers to water quality reports or drinking water quality reports. Some states like Minnesota are also beginning to build databases specific to PFAS contamination.
How Much PFAS Does Reverse Osmosis Remove?
Now that we know RO systems can treat PFAS, just how effective are they at removing PFAS? Reverse osmosis works because the RO membrane pores are so small they capture nearly all impurities. In fact, RO systems can remove 99.9% or more of these forever chemicals. Yes, they can be more pricey than some alternatives, but they’re easy to use and consistently delivers pure and clean water for drinking.
Activated carbon and ion exchange resins are two popular alternatives to traditional water filters due to their low initial cost and low ongoing maintenance requirements. Evidence suggests that these alternatives are not as effective as reverse osmosis at removing PFAS from drinking water. Short-chain compounds are more common today and more difficult to remove with just the activated carbon or ion exchange resin technologies.
Different Types Of Reverse Osmosis PFAS Treatment Systems
Reverse osmosis systems come in all shapes and sizes. Depending on your circumstances, there will be a RO water filter that works best for your needs. Whether its an under-sink unit, or a whole house system, here are some of the different options:
Point-of-Use RO
A point-of-use RO system address a single source, as opposed to a whole house RO system. The most popular point-of-use option is an under sink RO water filter system. This is hooked up to the water supply under your sink to ensure that your family members have access to clean water. The under-sink units come in either tank-based or tankless.
Because under sink ROs have been around for many years, they are also the most affordable option. If you live in a tiny home with little storage space, a tankless reverse osmosis system may be your best option. This innovative technology eliminates the need for the traditionally bulky tank under kitchen sinks.
Countertop RO
If you don’t want to deal with installation, a countertop RO is the way to go. This also makes them perfect for apartments, RVs, or anywhere on the go with access to electricity. Countertop RO systems consist of small, compact filter units that combine multiple filtration stages on a kitchen countertop. The filtration system is attached to the sink’s faucet or a water container to create purified tap water.
Whole House RO
Also known as point-of-entry RO systems, because it is installed right where the water supply enters your house. All the water that enters your home will be purified by this system. They are ideal for homes with a heavily contaminated water source. Conversely, undersink ROs are used primarily for drinking or cooking water. The whole house RO will take care of water for drinking, showering, washing machines, etc. The whole house RO generally consists of a pre-filter, sediment filter, RO membrane cartridge, and carbon post-filter.
Do all In-Home Water Filters Remove PFAS?
Reverse osmosis has been shown to be extremely effective. Unfortunately, not all in-home drinking water filters can effectively eliminate PFAS. According to Duke and NC State researchers, most filters are only partially successful in eliminating PFAS. Several of them, if not serviced regularly, might actually make matters worse. Here are the best alternatives to reverse osmosis for PFAS removal from your water at home.
Boiling Water
Boiling water does not remove PFAS. It is an easy and effective way to purify water at home. It can kill disease-causing microorganisms such as bacteria and viruses in the water. However, it cannot eliminate toxic metals and other impurities.
Brita Filters
Brita filters do not specifically remove PFAS from drinking water. You can find Brita filters in several water bottles and pitchers. These filters can be used to get rid of contaminants in water that might make it smell bad, taste bad, or be unsafe to drink. Their conventional filters remove chlorine and mercury from water by employing carbon in a sieve-like fashion. Ion-exchange resin is included in Brita filters to remove heavy metals like zinc, copper, and cadmium.
Granular Activated Carbon (GAC or Charcoal Filters)
Activated carbon filters work well with long-chain variants like PFOA and PFOS, but shorter chain PFAS do not adsorb as well in carbon [4].This filter is designed to slow down the growth of bacteria. Carbon blocks are inexpensive and effective in filtering out contaminants and chlorine. Since it has a reasonable flow rate, this type of filter can help in the retention of essential minerals. They are often a complement to RO systems as a pre-filter to the reverse osmosis membrane.
Ion Exchange Resins
The negatively charged PFAS ions are attracted to the positively charged anion resins in ion exchange filters. Water is filtered through a filter containing specialized resin. This resin is made to filter out harmful dissolved ions from water and substitute them with others.
Ion exchange is an effective water filtration method because it can eliminate many inorganic contaminants, including arsenic, sulfates, uranium, fluoride, nitrates, etc. This filtration method can also purify water by removing certain minerals.
Distilling Water
As one of the most efficient water purification methods, distillation involves evaporation and re-condensation of water. It eliminates all trace contaminants while leaving behind just pure water. Most notably, you won’t ever have to buy new filter cartridges. The drawbacks are that distilled water is described as tasting “flat”. It also takes several hours to distill one gallon of water.
Drawbacks of Using Reverse Osmosis For PFAS Treatment
Wastes Water
Yes, reverse osmosis “wastes” some water. There will be some rejected water due to the high level of filtration achieved by RO. While around 75% of incoming water is discarded, only about 25% is actually recovered by water stations. The most efficient approach to prevent this from being wasted is to save it for later use in the garden or for flushing.
Filter Replacement Costs
The cost per gallon of water produced is minimal when the system is purchased and installed. However, routine filter maintenance and replacements are costly and must be done frequently. Despite its low maintenance requirements, RO systems require annual cleaning and sterilization.
Higher Purchase Price
Reverse osmosis is also highly expensive, with some whole-home devices costing thousands of dollars. However, while the high cost does shorten the time it takes to filter water, it also wastes a lot of water in the process.
Requires Installation
You must consider several factors before installing a reverse osmosis system. Think about the plumbing factors, the space required, an outlet’s availability, and the electrical source.
FAQs For Reverse Osmosis PFAS Removal
What water treatment technology is best for PFAS at home?
Activated carbon, ion exchange resins, and high-pressure membranes are certain technologies that can potentially remove PFAS from your drinking water. In fact, these technologies are in drinking water treatment facilities, hospitals or building water systems, or residences.
Do any water filters remove PFAS?
The sad news is that not all domestic water filters can eliminate PFAS entirely from drinking water. Water purified by reverse osmosis or a two-stage filter reduced PFAS levels, including GenX, by at least 94%. On average, activated-carbon filters eliminated 73% of PFAS contaminants.
Does the reverse osmosis system remove PFOA and PFOS?
Yes, reverse osmosis is a common and highly effective method of treating water to eliminate PFOA and PFOS. It is a micro-filtration method for removing ions, compounds, and micro-sediment. It is more effective than activated carbon or ion exchange resins at filtering out PFAS from water, removing 99.9 percent or more contaminants.
Does boiling water remove PFAS?
False. PFAS cannot be eliminated by boiling. In fact, heat does not degrade PFAS but concentrates the chemicals, making them even more toxic if consumed. These chemicals are designed to extinguish fires and to remain stable under extremely harsh settings. Thus, it will take highly extreme conditions to degrade them.
Does distilling water remove PFAS?
Metals, microorganisms, toxins, bacteria, pollutants, sediment, minerals, and viruses are all eliminated during the distillation process.
A report found that the overall PFAS concentration in “purified” bottled waters (those commonly treated using reverse osmosis) was lower than in “spring” bottled waters (those not filtered via reverse osmosis).
Does Zero Water filter Remove PFAS?
The water is filtered through 5 levels in the ZeroWater filter. Therefore, it can remove all the suspended particles, inorganic compounds, and pollutants in drinking water. ZeroWater removes chlorine, lime, lead, glyphosate, PFAS (PFOS / PFOA), and microplastics.
