Frequently Asked Questions About Berkey Water Filters
Find answers to frequently asked questions about Berkey products here. These answers are updated from time to time. All answers are based on information from the manufacturer’s knowledge base, supplemented by our own experiences.
Usage
How long does it take for the water to flow from the top container to the bottom container?
The top container of your Berkey water filter should be completely filled in about 2 hours (a small layer of water will remain). The more successful the priming, the faster the flow rate will be. So if it takes longer than 2 hours, we recommend priming again. If this is your first time, the priming likely did not go well, and there is still too much air trapped in the Black Berkey filter elements. If you’ve been using the system for a while, this is a sign that you need to prime it again.
Priming ensures that the air is removed from the filters, which allows them to flow more quickly again. You can use the Priming Button, the Black Berkey Primer, or the blue Primer Rite for this. See also the instructional videos.
Is this your first time using the Berkey water filter? If so, here’s something important to keep in mind:
— the filtration rate will increase slightly during the first 12 to 24 hours.
If the speed remains low and water is still in the upper tank after well over 2 hours, please contact us and we’ll be happy to assist you.
There's still some water left in the top container—how is that possible?
It’s perfectly normal for a few centimeters of water to remain in the upper chamber. This is because the Black Berkey filter elements sit on a rim, and water naturally cannot pass over this rim. In addition, the water pressure is very low when there’s only a small amount of water left in the upper chamber, which prevents the water from flowing through. This applies when the water level is still just slightly above the rim of the filter element.
You can discard any remaining water if you're refilling the top chamber of your Berkey water filter.
The Black Berkey filter cartridges each have a different filtration rate—how is that possible?
This is possible! No two Black Berkey filter elements are exactly the same—they’re all unique. As a result, one filter element may be used up faster than another. These differences arise during production (the baking process), and while filters from the same box are often similar, this isn’t always the case. So it’s not a problem and nothing to worry about.
The flow rate of the Black Berkey filters has noticeably decreased. What can I do about this?
If you notice a significant difference in the filtration rate of the Black Berkey filters, this is a sign that it’s time to prime them again. Before cleaning, try to resolve the issue first by priming the Black Berkey filter elements again. You shouldn’t clean them too often; when using tap water, once every 6 months is sufficient. If priming doesn’t improve the filtration rate, then it’s time to clean them. But after cleaning, you’ll need to prime them again.
Priming ensures that the air is released from the filters, which allows them to flow more quickly again. After using them for a while, air gradually builds up in the filters again. You can use the Priming Button, the Black Berkey Primer, or the blue Primer Rite for this. See also the instructional videos.
If you do need to clean the filters, please refer to the instructions under the heading "Cleaning, Maintenance, and Storage."
The bottom chamber of my Berkey water filter is completely full of water, but (almost) no water is coming out of the faucet. How is this possible?
This is what's known as an "airlock." In this case, the containers fit together so perfectly that no air can get in. It's hard to predict in advance when this will happen, because sometimes they fit together too perfectly.
There are two ways to solve this problem:
Option 1. Use the Anti-Airlock Clip. If you ordered a Berkey water filter starting in the summer of 2022, you’ve already received it. This clip is included in the Priming Starter Kit, which has been provided free with every Berkey water filter starting in the summer of 2022. If you do not have the Priming Starter Kit , you can order the Anti-Airlock Clip separately from us; click here.
Place the clip on the rim of the lower chamber, with the rounded side facing outward. Then place the upper chamber back on top. This will allow sufficient air to enter, preventing a vacuum from forming, and the water will flow out normally.
Option 2. You can also try rotating the top container into different positions to see if that improves the fit and allows air to pass through. Another solution is to “roll” the lower housing:
- Carefully remove any Black Berkey filter elements from the system and set the upper housing aside.
- If already installed, remove the faucet from the lower housing.
- Place a towel on a smooth, hard surface. Place the lower chamber on its side on the towel, holding the towel firmly in place.
- Apply light pressure with both hands to the side of the lower chamber; roll the chamber back and forth across the hard surface. Focus your attention on the upper part of the lower chamber. This will slightly reshape the lower chamber and allow for proper airflow between the upper and lower chambers.
If you choose to roll the dice, it might not be resolved after just one try, but in that case, you could try again.
After filtering, there's still some limescale in, for example, a kettle. How is this possible?
It’s good to know that a Berkey water filter doesn’t completely remove calcium from the water. Larger amounts are reduced, and synthetic calcium is removed. However, a Berkey water filter retains beneficial minerals (those that occur naturally in water and are good for human health) in the water. And calcium is one of them. So you retain the mineral calcium in the water, and this can still cause some scaling. In short, a Berkey water filter is not designed to remove calcium from the water.
Water is leaking from the faucet connection—what's wrong?
If water is leaking from the faucet connection, it’s most likely because the faucet isn’t installed properly. So, empty the bottom tray and disassemble the faucet. Then check to make sure all the parts are in the right place. It’s important to have one rubber O-ring on the outside and one rubber O-ring on the inside. Next, reinstall the faucet and tighten the nut (on the inside) as much as possible. Then hold the nut on the inside in place and turn the faucet on the outside. You’ll notice that it tightens even further. Keep doing this until you can’t tighten it any further. If the faucet isn’t straight, do the following: release the nut on the inside and turn only the faucet on the outside until it’s straight. This is because the entire unit rotates as one piece. If you accidentally turn it too far, DO NOT turn it back. Doing so will loosen it again. So if you’ve gone too far, simply turn the entire unit again until it’s properly secured.
If done correctly, the faucet should no longer leak at the connection.
Water is coming out between the two containers—what's going wrong?
If water gets between the top and bottom chambers of your Berkey water filter, it means the bottom chamber is too full. This happens when the top chamber is refilled while the bottom chamber isn’t empty yet. In that case, the water simply continues to filter through, causing the lower chamber to overflow. The excess water then leaks out between the two chambers.
It’s best to fill the upper chamber completely the first time you refill it. Let this water run through. When you notice that the lower tank is almost empty (as indicated by the sight glass valve or the water pressure), refill the upper tank completely. You can do this because the upper tank is slightly smaller than the lower tank, and the filters in the upper tank take up space. The lower tank therefore has excess capacity compared to the upper tank. By doing it this way, you prevent water from leaking between the two tanks.
Can I use a Berkey water filter with a water softener?
The Black Berkey filter cartridges are designed to remove heavy metals, but they will not remove the mineral salts added by a water softener. This is because a water softener adds mineral salts to the water to make it softer. The salt used to soften water is not removed by a Black Berkey filter cartridge and will actually cause the cartridge to become clogged. You can still use a Berkey water filter if it’s possible to bypass the water softener. Most water softeners have a bypass valve or a way to divert water before it passes through the softener. Therefore, we strongly recommend using that water instead of running softened water through your Black Berkey filter cartridges.
Materials
What are the plug-offs made of?
There are three different types of locking plugs:
- Black blocker plugs are included as standard with all Berkey Light water filters and some stainless steel models. The black plugs are made of FDA-approved Buna rubber.
- Off-white stopper plugs (rubber cork) are available for the Berkey Light models and some stainless steel models. The off-white plugs are made of food-grade M18 pure natural rubber.
- White locking plugs (bolt and nut) are used in some stainless steel models. They come with a nut, a screw, and two transparent rings. The nut and screw are made of polypropylene. The rings are made of food-grade silicone.
Please note that the water in the lower chamber of your water filter will not come into contact with any of the plugs. This is because the water is filtered before it reaches the lower chamber.
Is the base of the Black Berkey filter element BPA-free?
Yes, the base of a Black Berkey filter element is BPA-free.
Cleaning, Maintenance, and Storage
When and how do I clean the Black Berkey filter cartridges?
Black Berkey filter elements do not necessarily need to be cleaned every time you clean the Berkey water filter housing (the lower and upper chambers). However, this may vary depending on the region and water source. In certain parts of the world, the water is much dirtier than in other areas, and it will be necessary to clean the elements more frequently—possibly even more often than cleaning the rest of the system requires. If your water is muddy or very dirty, we recommend pre-filtering it by running it through some kind of cloth—such as a shirt, sheet, bandana, etc.—before filling the Berkey water filter with it. Although this isn’t necessary, it helps keep the cleaning schedule for the filter elements to a minimum by trapping debris that could clog the pores of your Black Berkey filter elements.
When is it time to clean your filters?
- You should clean the elements when you notice a significant decrease in flow rate.
- You may also want to consider cleaning the elements periodically. For example, every 6 months (IMPORTANT!! Never more often than once every 6 months, unless you notice a decrease in flow rate). The advantage of this is that you won’t experience a slow flow rate. Cleaning the elements on a regular schedule is at your discretion. This is a suggestion, not a requirement.
How do you clean the filters?
- Empty your Berkey water filter and remove the Black Berkey filter cartridges.
- Use a scouring pad or a stiff brush and gently scrub the outside of the Black Berkey filter elements under cold running water.
- Reinstall the filters. If you're not familiar with this process, check out our instructional videos.
- Reinstall the Black Berkey filter cartridges in the Berkey water filter.
- Finally, fill your Berkey water filter and, if necessary, perform a red dye test as described in the instructional videos to ensure that the Black Berkey filter elements are still effective.
How should I store my Black Berkey filter cartridges, and how long do they last?
Once you've used your elements:
The storage method depends on how long the Black Berkey filter elements will remain unused:
If the filters are not used for 4 to 15 days and you want to avoid having to prime them again, remove the filters from the water filter, place them in a sealable bag or container, and put them in the front of the refrigerator to prevent them from freezing. This keeps the filters mostly saturated (wet), so that re-priming is usually not necessary. If, for any reason, the filters are working more slowly than usual, prime them again until water droplets begin to form on the outer wall of the filter for 10 seconds.
For long-term storage, we recommend drying the filters and storing them in a sealed container. It’s important that they are completely dry before being stored long-term to prevent potential bacterial growth. One way to dry your filters is to leave them on a windowsill for one to three days and let them air dry. We also offer a tool to assist with both priming and purging: the Black Berkey Primer. The advantage of purging Black Berkey filter elements with the Black Berkey Primer is that they dry very quickly. Once the filters are completely dry, place them in a storage bag, such as a large, sealable bag. The elements are extremely powerful and can absorb odors and smoke from the air. By sealing them in a bag, they cannot absorb odors from the air. When you’re ready to use the filters again, clean them by scrubbing the outside with a scouring pad or a stiff brush. Then prime the filters again—either by hand or with the Black Berkey Primer—before reinserting them into the water filter.
In theory, the Black Berkey filter elements have an unlimited lifespan.
**Please note that the storage methods listed above apply only to Black Berkey filter cartridges.
If you've never used these elements before:
If the cartridges are unopened and still in their original packaging, make sure not to store them in a room with strong odors (such as a laundry room or garage). Since the elements contain carbon as one of their components, they may absorb odors from the room in which they are stored. For example, if they are stored in a laundry room, they may pick up the scent of strongly scented items such as laundry detergent.
** If you are also storing the top and bottom chambers of your Berkey system, it is best to empty both chambers before storing them. Water that sits for a long time promotes the growth and reproduction of bacteria. We recommend washing your Berkey system with soapy water before letting it dry.
How should I store my Berkey Fluoride & Arsenic filters (PF-2)?
If you've already used the elements:
The Berkey Fluoride & Arsenic filter cartridges (PF-2) can be stored in the refrigerator for a short time (see below); however, be sure not to store them in the freezer. To do this, remove the filters from the water filter, place them in a sealable bag or container, and store them toward the front of the refrigerator to prevent them from freezing.
The Fluoride & Arsenic filter cartridges (PF-2) last only one year. “Short-term” therefore refers to the next use within that year. Keep in mind that the longer the cartridges are not in use, the more their ability to filter fluoride and arsenic may decrease. In addition, it is advisable to prime them every 2 weeks while they are in storage to keep the filtration process active.
If you've stored them in the refrigerator, we recommend priming the Berkey Fluoride & Arsenic filter elements (PF-2) again before using them. Do this for up to 1 minute in each direction.
The Berkey Fluoride & Arsenic filter cartridges (PF-2) should not be allowed to air-dry, as this can cause some bacterial growth in the filters.
If you've never used these elements before:
If the batteries are unopened and still in their original packaging, make sure not to store them in a room with a strong odor, such as a laundry room or garage. Since the elements contain carbon as one of their components, they may absorb odors from the room where they are stored. For example, if they are stored in a laundry room, they may pick up the scent of strongly scented items such as laundry detergent.
Tests and Results
Does a Berkey water filter also remove PFAS?
The Environmental Working Group (EWG) tested 10 water filtration systems for their ability to remove 25 individual per- and polyfluoroalkyl substances (better known as “PFAS”) from tap water. In the EWG’s tests, the Berkey water filter (equipped with Black Berkey filter elements) removed PFAS to undetectable levels, earning the system a place in the “Best Overall” category.
The Berkey water filter was also praised for its large capacity compared to other water filters tested, and its “exceptionally long filter life” (each pair of authentic Black Berkey filter elements can filter up to approximately 22,700 liters (11,350 liters each) of tap water before replacement is recommended). CBS News Philadelphia produced a news report on the EWG tests, in which the Berkey water filter is mentioned. You can watch it here. CBS Colorado also mentioned the Berkey water filter in a TV news segment about the EWG test, which you can watch here.
The EWG’s water filter test results were released a week after the United States Geological Survey (USGS) published its study showing that the drinking water of nearly half of U.S. households contains at least one type of PFAS. PFAS have been in use since at least the 1950s and have been linked to a wide range of health problems in humans, including certain types of cancer and developmental, metabolic, and immune disorders, among others. PFAS are called “forever chemicals” because they take a very long time to break down in the environment.
To protect yourself from PFAS in your drinking water, you need to make sure you have a final filtration system. Consider, for example, a Berkey water filter equipped with the powerful Black Berkey filter elements, which have been independently tested by accredited laboratories to remove perfluorinated chemicals to levels below the detection limit.
Read more:
- EWG: News Release | Guide to PFAS Water Filters
- CBS Colorado: Which Water Filters Can Block PFAS
- CBS News Philadelphia: Environmental Group Tests to Find the Best Water Filters for Removing PFAS
- New Study: “Forever Chemicals” Found in Nearly Half of U.S. Tap Water
- Do Black Berkey® Elements Remove PFAS and Other PFCs from Drinking Water?
- Black Berkey® Elements: The Final Barrier Against PFOA and Other PFCs in Drinking Water
Laboratory test results for the Berkey water filter
For all laboratory test results for the Berkey water filter: click here. You will be redirected to the manufacturer’s knowledge base, where all results are listed on a single page. These results cover all tests conducted using the Black Berkey filter elements, which are the filter elements used in the Berkey water filter.
This page also includes the test report for the Berkey Fluoride & Arsenic (PF-2) filter cartridges.
How do I know if my filters are working properly? – Red dye test
IMPORTANT PRELIMINARY INFORMATION
The red food coloring test is intended solely to verify that your Berkey water filter is assembled correctly—ensuring that no water is coming from anywhere other than the stems of the Black Berkey filter elements and that the filters are not exhausted. Berkey Water Systems does not have independent test results showing the percentage by which the red food dye is filtered out. Therefore, they cannot officially claim that this contaminant is reduced. Consequently, if the instructions below are not followed—for example, if a higher concentration of red food dye is used—it is likely that the dye will not be reduced by 100%. It is therefore important to follow the instructions below carefully, paying particular attention to the amount of red food coloring used and ensuring that the test is not performed more than twice a year.
The Black Berkey filter cartridges are powerful enough to remove red food coloring from water. By conducting a red food coloring test, you can be sure that your Berkey water filter system is working properly.
GUIDELINES
- We recommend performing this test the first time you use the system and then every six months (after cleaning) to ensure that the Black Berkey filter elements are working properly.
- The red dye test is intended only for Black Berkey filter cartridges and NOT for other filter cartridges (such as the Fluoride & Arsenic filters) that do not filter out the dye. This test is also not recommended for the Sport Berkey water bottle.
- Make sure the food coloring is RED. Red food coloring (unlike the other colors) does not contain any minerals, so the system recognizes it as a contaminant. Also, do not use natural red food coloring (such as beet juice), as this is not recognized as a contaminant either. The goal is to use a synthetic red food coloring, so be sure to use theoriginal red food coloring.
- The red dye test must be performed after the Black Berkey filter elements have been primed.
CONDUCTING THE TEST
NOTE: Check out ourinstructional videos for a clip showing how to perform the red dye test.
1. Start with an empty water filtration system (upper and lower chambers) and remove any fluoride filters (if installed).
2. Place only the upper chamber (with the Black Berkey filter elements installed) on glasses of similar size (so that the filter stems protrude from the glass). This makes it easy to immediately see which filter passes and which fails the test.
3. In a separate pitcher, add 3 drops (= 0.15 ml) of food coloring per liter of water and mix (a bottle of original red food coloring is enough to perform a full test multiple times). Pour the red water into the upper reservoir until the filters are completely submerged. Note: Never pour red food coloring directly from the bottle onto the filters or into the upper reservoir. Always mix the food coloring with water in a separate pitcher first.
4. Allow the water to filter from the upper reservoir into the glasses below. When the glasses are three-quarters full, pour the remaining water out of the top reservoir. Note: The glasses may fill at different rates.
5. Check the water in each glass. It should be clear, without a pink or red tint. If the water in any of the glasses is red or has a pink tint, that specific filter may be defective or spent. See below.
IF YOU NOTICE A RED COLOR IN THE WATER, CHECK THE FOLLOWING:
1. Are the wing nuts tightened properly? Do not tighten the wing nuts with a tool; they should be tightened by hand until you feel resistance—that is sufficient. If the wing nuts are too tight, this can damage the threads on the stem and/or the grooves on the wing nut. This can affect the seal. If this has occurred, please contact us.
2. Are you using natural red food coloring or a different color of food coloring? Non-natural red food coloring is the only type recommended for this test.
3. Is the black ring from the Black Berkey filter elements also inside the top housing, and is the wing nut tightened at the bottom? If the black ring is on the outside of the bottom housing (i.e., right next to the wing nut), this is not a proper seal. As a result, the test will fail. Place the black ring on the inside of the upper chamber and repeat the test.
4. Do the plug caps properly seal the unused holes (if applicable)? Are the plug caps securely installed so that the holes are truly sealed? For plug caps with a bolt and nut, there must be a sealing ring on both sides (not just on one side). If the plugs are leaking, this will cause the test to fail. Tighten the plugs more securely and repeat the test.
5. Are you retesting a filter element that failed? If so, make sure to rinse this filter element and prime it again before retesting. Also, ensure that all the water has been drained from the lower container (or glass). If you’re using the lower container or a glass to collect water, first rinse it thoroughly with clean water. Now you’re ready to repeat the test.
6. If you’ve done all of the above and a filter element still fails the red dye test, please contact us. Black Berkey filter elements come with a two-year warranty (in periods). Review the warranty terms.
NOTE: Check out our instructional videos for a clip showing how to perform the red dye test.
Does a Berkey water filter contain or filter out graphene oxide?
The Black Berkey filters are made from a patented blend of various components, including, for example, high-quality carbonized coconut shell. Berkey Water Systems confirms that there is no graphene oxide in the composition of the filter elements.
Furthermore, Berkey Water Systems does not have any test reports available that verify the reduction of graphene oxide by the Black Berkey filters. Without test results, they cannot claim that the filter elements are capable of reducing or removing this contaminant.
What do the results from a TDS meter indicate?
A TDS meter does not detect much of a difference between unfiltered water and water filtered through a Berkey filter. This is normal, and the reason has to do with what a TDS meter actually measures. According to tdsmeter.com , “Total Dissolved Solids (TDS) is the total amount of mobile charged ions, including minerals, salts, or metals dissolved in a given volume of water, expressed in units of milligrams per unit volume of water (mg/L), also known as parts per million (ppm).” TDS is directly related to the purity of water and the quality of water purification systems and affects everything that consumes, lives in, or uses water—whether organic or inorganic—for better or for worse.”
This statement is both correct and incorrect. It is correct in describing what a TDS measurement consists of, namely the “total amount of mobile charged ions, including minerals, salts, or metals dissolved in a given volume of water.” It is incorrect in its conclusion that TDS is related to the purity of the water and the quality of the water purification system. If the measure of a water filtration system were how close it could bring the water to pure H₂O, then it might be correct. But people need minerals to live. So beneficial minerals in your water are actually a good thing. A high-quality water filtration system should filter out substances that are harmful to your body while leaving behind the beneficial ones, such as minerals. Black Berkey filter cartridges are designed to leave healthy and beneficial minerals in the water and to remove unwanted heavy metals such as lead and mercury, as well as sedimentary minerals like iron oxide and aluminum.
So, if you use a TDS meter, you’ll find that the reading is roughly the same both before and after the water has passed through the Black Berkey filter cartridges. And that’s exactly right. The Black Berkey filter cartridges retain all the beneficial minerals. So, of the substances that a TDS meter can actually detect, the Black Berkey filter elements will remove only the undesirable heavy metals—such as lead and mercury—as well as sedimentary minerals like iron oxide and aluminum. That’s why the TDS reading won’t change much, unless your water contains a significant amount of heavy metals or sedimentary minerals.
A TDS meter does not measure the amount of biological and chemical contaminants (including, for example, chemicals, medications, hormones, many pesticides and their residues, bacteria, and viruses). The most important thing is not to rely solely on a TDS meter to determine whether your water is safe. You can have water with a low TDS level that still contains harmful bacteria. You can have water with a high TDS reading that is completely safe (e.g., pure, uncontaminated seawater… although you wouldn’t drink it, but that’s only because it’s mineral salt). So make sure you know what a TDS meter actually measures.
Replacement
How do you know when the Fluoride & Arsenic filters (PF-2) need to be replaced?
The Fluoride and Arsenic filters (PF-2) last for up to 3,700 liters of water or 1 year, whichever comes first. Of course, it’s very difficult to keep track of the number of liters, so we recommend using them for one year.
How long do Black Berkey filters last?
The filter's lifespan varies depending on the source water and the level of contamination. The recommendation for when to replace the filter depends on several factors. For example, when filtering chlorine, the filters last for more than 45,000 liters per pair. However, there are various contaminants in the water, and their concentrations can vary.
The Black Berkey filters are designed to last for many years. However, we now live in a different time than we did a few years ago. The number of contaminants has only increased, and they have become increasingly severe (think, for example, of PFAS or the significant rise in pharmaceutical residues, pesticides, etc.). This has a huge impact on the filters, meaning they need to be replaced a bit sooner. Of course, it’s difficult to keep track of exactly what’s in the water and in what quantities, which is why we recommend replacing Black Berkey filters every 3 years at most when using tap water. If you use water from another source, we recommend replacing them sooner.