Berkey Water Filters and TDS Readings

TDS (Total Dissolved Solids) is the least effective type of test to determine whether water is suitable to drink. Sadly, many water filter companies use a TDS meter reading in their marketing campaigns touting their results, using it as a marketing ploy to trick an uniformed public into thinking their water is better than all others.

In this article we'll help explain what a TDS reading means, along with why many customers experience an increase in this TDS readings during the initial break-in of the black berkey filters.

Total dissolved solids (TDS) is the combination of all inorganic and organic contents contained in a liquid having a molecular, ionized, or micro-granular (colloidal sol) dissolved form. These contents could include minerals like salt, magnesium and potassium, along with heavy metals such as mercury and lead.

Total dissolved solids are normally only discussed for freshwater systems, since salt comprises some of the ions constituting the definition of TDS. Although TDS is not generally considered as a primary pollutant (e.g. it is not deemed to be associated with health effects), it is instead used as a general indicator of the presence of a broad array of chemical and mineral contaminants that could be in water.  You'll see these TDS readings or minerals listed on the back of bottled water sometimes.

bottled_water_labels Here's the PH and TDS readings of some popular bottled water brands.

Higher or lower TDS readings do not always mean better when it comes to minerals. In the cases above, one bottle water may have simply higher potassium levels than the other, so their TDS reading would be higher to account for this.

What About Heavy Metals?

This is where a TDS meter reading can have value. Remember, the TDS reading does not only cover beneficial minerals, it also includes any heavy metals that may be the water. And, it's pretty well known that we don't want to be ingesting heavy metals.

So, if you know you have heavy metals in your drinking water, then this would be the only time you'd want the TDS reading to go down after running through a water filter.

But now you're probably wondering, "Well, how do I know if there's any heavy metals in my water in the first place?" The answer is that you'd have to test it. There's no way to know what the specific levels of minerals or heavy metals are unless it's tested by a lab.  If you're on city water, then you can typically contact them for these details. If you're on well water, then you would need to have your water tested by a local lab facility.

Important note: City water tested levels are at the originating water facility, and do not account for any contaminants that may be picked up in the pipes along the way to your home.

And this is why a TDS reading has limited value. It only gives you a total aggregate number, but you never know if this number represents beneficial minerals or harmful heavy metals.

What about Berkey And TDS readings?

The Black Berkey element formula utilizes two ingredients that will add TDS to any water passing through the elements during it's initial break in (first 5 full system flushes). Firstly, all filters that utilize any form of carbon in their formulation increase TDS, as carbon fines (invisible) will attach to water as it passes through the element. Many filters utilize nano-sized particulate in high quality carbon micro fines to create the outer "mean porosity" and interior tortuosity of the block or cross section of the filter elements.

Several tests are performed on automated lines to insure exact porosity and final destructive tests determine the durability of the element. Two of these tests purge or remove most of these fines, which enable the flow of water through the element through open micropores. Additional fines are removed during initial black berkey priming, however there may still be some non-harmful nano size carbon micro fines present in the water after filtration (first 5 flushes).

The flagship Black Berkey Filter Elements will remove all heavy metals from the water while leaving in the beneficial minerals. The flagship Black Berkey Filter Elements will remove all heavy metals from the water while leaving in the beneficial minerals.

The Drinking Water Regulations in the United States typically regulate TDS not to discover micro fines of carbon but rather unsuspecting organic and inorganic chemicals along with other micro pollutants - like heavy metals.

The second and probably most common reason for increased TDS in water run through a Black Berkey element is the ion exchange media. Ions are a form of TDS, and as indicated above, are found in sea water and in water subject to any substance that ionizes liquids and or air (air ionizers) etc. There are millions of ions in the air and they are essential to life. Ions do not comprise a health risk but rather, a health benefit. While TDS increase will likely be on the very extremely low end (1-5 TDS increase) may continue to exist for the life of the filter.

Another simple test would be to test water before and after a pass through an inexpensive Carafe style water filter like a Brita. You will observe the same increase in TDS during break-in.

Final Wrap Up

The benefit of the black berkey filters is that they have been designed to remove any harmful heavy metals from the water while leaving in the beneficial minerals. So, if you do not have heavy metals in your water, you will most likely not see any change in your TDS readings pre and post the filtration through the berkey.

We hope this helps with any questions or concerns. Again, TDS is actually the least effective type of test to determine whether water is suitable to drink. In actuality, most involved in this type of discussion are unaware and don't understand the variety of sciences concerning water filtration.

Typically this type of discussion arises from those promoting the use of RO and Distillation methods, which drastically reduce TDS. Unfortunately, such water is acidic, is never found in nature, and therefore can confuse the body. Research has shown that when drinking this water for extended periods of time, the body will typically attempt to re-mineralize itself by robbing essential minerals from other parts of body. For more information on this issue please see the below references:

6 thoughts on “Berkey Water Filters and TDS Readings”

  • Trisha Smet

    I bought my mother a Berkey unit and she was thrilled to be able to drink her tap water. She replaced her filters in March 2017. However, she was just told, based on a water filtration company that offered a FREE water analysis that her water has a TDS of 700. She was told that this level is deemed unsafe for human consumption.
    Of course, she is alarmed. I've entered her email address so you can inform her directly.
    Please advise.

    • Dan DeBaun

      Hi Trisha -

      The TDS meter only measures dissolved solids such as heavy metals and beneficial minerals, NOT chemicals, bacteria, etc... Without a detailed breakdown of what the levels of each dissolved solid in that test read out as, it would be difficult to respond to this company's claims accurately. That TDS reading of 700 could be all minerals or it could be heavy metals. The EPA's recommended maximum level of TDS in water is 500, however there is no scientific evidence that TDS makes any difference, and no health impact has been identified below 2,000. The Berkey will remove the heavy metals from the water, and not the beneficial minerals, so it is likely that this reading represents all beneficial minerals. If there is still concern from you or your mother, I recommend getting a detailed reading of what each dissolved solids level reads out at.


  • Zasele

    I just used a TDS EZ tester on my Big Berkey filter water and it reads 260-262. I measured my tap water and it's 255. How's that even possible when the filter is suppose to take away, not add to the water. What's going on?

    • Dan DeBaun

      Hi Zasele -

      A TDS meter measures only Total Dissolved Solids or minerals; dissolved solids are simply dissolved minerals in an ionic form. A TDS meter does not measure the amount of biological and chemical contaminates. Black Berkey elements are designed to leave in your water the healthful and beneficial minerals and to extract only the unwanted heavy metals such as lead and mercury as well as sedimentary minerals such as iron oxide and aluminum. Therefore, your TDS reading will not change much unless you have a significant amount of heavy metals or sedimentary minerals in your water. When it comes in a little higher, this is a result of either the dust wash off from the break in of the filters, or you have some calcium or other mineral deposits in the lower chamber, that are increasing the post filtration mineral content reading on that meter.

  • Tracy Beaudry

    there are many people who believe we shouldn't have too many minerals in our water because we do nothave gizzards and can then get kidney stones... isn't that why many people do reverse osmosis because they don't went too many minerals in the water... and be harmful to your gut

    • Dan DeBaun

      Hi Tracy -

      We would preface our response by saying one should consult a doctor if they believe this is a serious issue that may impact their body. However, clinical research does not necessary back up these beliefs that mineral water is harmful. In fact, just the opposite, as mineral water is considered healthy for you by the mainstream and alternative medical communities. Doctors actually sometimes prescribe mineral water for those to help with alleviating already existing kidney stones.

      For the very most part, mineral-free water is not something that is found in nature. Our bodies have been drinking water with minerals for as long as we've existed on this earth, so I believe it would be safe to say our bodies have adapted to these minerals in our water. The very recent theory that drinking mineral-free water for extended periods of time is somehow good for us, would seem counter to common sense. (We do believe short term mineral-free water can have bodily benefits)

      With that being said, every person's body and nutritional needs are different, and given this, there may be times where having a lower or higher mineral content may be more therapeutic for the individual. For example, some folks may have abnormally high levels of calcium in their water, and it's possible it may make sense to take steps to decrease this water intake. We again would advise a doctor consultation if this is an area of concern, where proper blood work, etc can be done for that specific individual.


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