We get this question often and I hope I can help explain your TDS meter’s Parts Per Million or “ppm” readings. 

Our filters utilize a patented Ionic-Adsorption micro-filtration process that features a 2.0micron pore size.

This allows us to have the Highest Contaminant Reduction in the industry!

However, many customers are curious as to why our filters don’t reduce the Total Dissolved Solids, or “TDS” found in tap water.

Here’s why:

The TDS is not an accurate indication of water quality.

Total Dissolved Solids aren’t linked with adverse health effects. In fact, the main component of TDS is: minerals (such as calcium, potassium, iron etc.). Higher TDS readings often indicate higher levels of the trace minerals in the water which is actually desirable.

The best part about our product is that it is able to filter out the chemicals, disinfectants and heavy metals in ONE STEP but is also able to leave the healthy mineral content of the water in tact.

Our filters are not designed to remove minerals such as other Reverse Osmosis or Distillation do.

The recent popularity of inexpensive and portable TDS meters has now made testing one’s tap water fairly common practice. However, these devices really don’t tell the whole story, and most people are led to believe that high levels of TDS is bad when in fact, bottled mineral water will have readings in excess of 250ppm!

So if you are testing your water with a TDS meter, know that your readings will vary, and that a TDS reading higher than the tap water is NOT an indication of a faulty filter.

How can this be one might ask?

As a by-product of our patented ionic-adsorption filtration process, the charge of water passing through the filter changes slightly. This can result in TDS readings HIGHER than the tap water itself. The TDS meters are sensitive to changes in positive (+) or negative (-) charges and a higher reading DOES NOT reflect a poor water quality. It actually indicates that the filter is working and doing it’s job to remove contaminants!

1) One of the things the TDS meter does is measure the conductivity (positive or negative charge) of the water. Our filters use an Ionic adsorption process leaving the water with a slightly positive charge. This will cause the meters to show a higher TDS reading when in reality nothing has been added to the water. In essence, it proves that the filter is working.

2) If the filters haven’t been properly flushed before they test it, there can be some residual carbon from the filter that falls off. Our filters are made from a form of Activated Coconut Carbon and during shipping some of the carbon shakes off naturally which could result in a higher TDS reading. But the carbon we use is EPA approved and has NO Health effects whatsoever. 

For more information about our filtration technology please visit us online at http://www.clearlyfiltered.com/pages/test-results

Thanks for reaching out and we hope you continue to enjoy your ClearlyFiltered products!


  • Posted On October 24, 2018 by Brian

    well if its really removing heavy metals that would cause the tds readings to go down then since metals are a solid.

  • Posted On April 25, 2018 by Muhammed rasif

    I’m from india my doubt is does vessal filters remove every condaminents in water

  • Posted On September 18, 2016 by Tami Duncan

    What exactly is filtered out? I’m wanting to filter out nitrates…does your filter do this? Thanks.

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