Using a TDS Meter on Berkey Water

Using a TDS Meter on Berkey Water

What is a Total Dissolved Solid?

According to, “Total Dissolved Solids (TDS) are the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water, expressed in units of mg per unit volume of water (mg/L), also referred to as parts per million (ppm).”

It is important to understand, beneficial minerals (like calcium, potassium, etc.) and harmful contaminants (ie heavy metals and sedimentary minerals) are both considered total dissolved solids.

How Berkey Filters Water


TDS Meters and Water Quality

A TDS meter cannot identify between; healthy ionic minerals, harmful sedimentary minerals, and heavy metals. In other words, TDS is not a good way to measure the "cleanliness" of water because beneficial minerals are also considered total dissolved solids.

A TDS reading of 0 would indicate the absence of all TDS, including healthy beneficial minerals, bad minerals, and heavy metals, this type of water is also called “dead water”. Learn more about dead water in our Berkey vs Reverse Osmosis comparison. Zero Water Filters also utilize a TDS meter to gauge the filter life and water quality, read more about how Berkey stacks up against Zero Water Filters.

It is our belief at Berkey Filters, that a water purification system should filter out things that are harmful to your body, but leave in the helpful things such as beneficial minerals. The Black Berkey elements, utilized in all our Berkey Systems, are designed, to do exactly that! The Berkey Black filter’s proprietary design allows healthful beneficial minerals (like calcium, potassium, etc.) to remain in your water and remove; chemicals, harmful sedimentary minerals, heavy metals and many other contaminants (200+ in total) see our independent test results!

When a TDS meter is used on Berkey Water, the reading both before and after the water has gone through the system is about the same. This is because the Berkey Filters leave beneficial minerals (a TDS) in your water. This will be the case unless you have a significant amount of heavy metals or sedimentary minerals in your pre-filtered water.

How Berkey Filters Water

Testing Berkey Water

Rather than using a TDS meter on your Berkey Water, we recommend running the Red Dye test. This is a simple test you run on your Black Filters to visibly see if the Black Filters are removing the chemically colored red food coloring. Please note only McCormick’s Red dye should be used as it is the only purely chemically composed red food coloring. Do not use gel coloring.

Important side note: When using a Berkey system for the first time, it is common for a TDS meter to initially show a higher reading, due to the manufacturer’s process dust and carbon that are compressed in the media of the filter element. After running four to five batches of water through your Berkey system, you should notice a this higher reading is reduced.