Total Dissolved Solids - 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.
Are Total Dissolved Solids - TDS?
"Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. This includes
anything present in water other than the pure water (H20) molecule and suspended solids. (Suspended solids are any
particles/substances that are neither dissolved nor settled in the water, such as wood pulp.)
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).
In general, the total dissolved solids concentration is the sum of the cations (positively charged) and
anions (negatively charged) ions in the water.
Parts per Million (ppm) is the weight-to-weight ratio of any ion to water.
Total Dissolved Solids - 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,
whether for better or for worse.
A TDS meter is based on the electrical conductivity (EC) of water. Pure H20 has virtually zero conductivity.
Conductivity is usually about 100 times the total cations or anions expressed as equivalents. TDS is calculated by
converting the EC by a factor of 0.5 to 1.0 times the EC, depending upon the levels. Typically, the higher the
level of EC, the higher the conversion factor to determine the TDS. NOTE - While a TDS meter is based on
conductivity, TDS and conductivity are not the same thing. For more information on this topic, please see our FAQ
Where Do Dissolved Solids Come
Some dissolved solids come from organic sources such as leaves, silt, plankton,
and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during
the winter, and fertilizers and pesticides used on lawns and farms.
Dissolved solids also come from inorganic materials such as rocks and air that may
contain calcium bicarbonate, nitrogen, iron phosphorous, sulfur, and other minerals. Many of these materials form
salts, which are compounds that contain both a metal and a nonmetal. Salts usually dissolve in water forming ions.
Ions are particles that have a positive or negative charge.
Water may also pick up metals such as lead or copper as they travel through pipes
used to distribute water to consumers.
Note that the efficacy of water purifications systems in removing total dissolved
solids will be reduced over time, so it is highly recommended to monitor the quality of a filter or membrane and
replace them when required.
Why Should You Measure the TDS Level in Your
The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million
(ppm)) for TDS. Numerous water supplies exceed this level. When TDS levels exceed 1000mg/L it is generally
considered unfit for human consumption. A high level of TDS is an indicator of potential concerns, and warrants
further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and
sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others)
may also be dissolved in the water.
Even the best water purification systems on the market require monitoring for TDS to ensure the filters and/or
membranes are effectively removing unwanted particles and bacteria from your water.
Why is low TDS pure water healthier to
We are all affected by toxic minerals and chemicals found in the air and in our food on a daily basis. Water is
the only way the body has to flush out these toxins. The purer the water is to start with, the higher its capacity
to collect and cleanse these compounds from the body.¹
Why is it especially important for children to
consume low TDS pure water?
A child’s immune system and detoxification system are still developing throughout early
childhood and teen years. Exposure to even very low levels of toxic chemicals or lead in drinking water at a young
age can lead to increased risks of degenerative diseases and learning disorders in later years. Since many of the
crucial defense systems that help protect adults from disease and environmental pollutants are not fully developed
in children, they are much more sensitive to contaminants. A child consumes 3 times as much water per pound of body
weight than an adult does, so they get a much bigger dose of the contaminants in our water. Their developing bodies
are simply much more sensitive.²
Currently, the health standards that determine how much and what levels of contaminants we
are permitted to consume in our drinking water are all based on the potential effects on
How can water with high TDS be undesirable or
It may taste bitter, salty, or metallic and may have unpleasant odors
High TDS water is less thirst quenching.
High TDS interferes with the taste of foods and beverages, and makes them less desirable to consume.
Some of the individual mineral salts that make up TDS pose a variety of health hazards. The most problematic are
Nitrates, Sodium, Sulfates, Barium, Cadmium, Copper, and Fluoride.
According to Dr. Allen E. Banik with Carlson Wade, "If a person drinks 2 pints of water a day, this will total
4500 gallons of water passing through his body over a 70 year span. If the water is not totally pure, this 4500
gallons will include 200-300 pounds of rock that the body cannot utilize. Most will be eliminated through excretory
channels. But some of this will stay in the body, causing stiffness in the joints, hardening of the arteries,
kidney stones, gall stones and blockages of arteries, microscopic capillaries and other passages in which liquids
flow through our entire body.³"
I'll make a modification to the statement by Dr. Banik and Wade. Some of the Total
Dissolved Solids may be good minerals calcium, magnesium, selenium, zinc, etc., and may have a positive effect on
your health. Some to the TDS may be toxic levels of chloride, sulfate, iron, lead, fluoride, etc., and may have a
negative effect on your health.
The only way to know if Total Dissolved Solids (TDS) may have a negative effect
on your and your families body is to a water test:
1. Waterwarning.com (Charles Strand)
3. “Water can undermine your health,” by Norm W. Walker
4. “Your water and Your Health,” by Dr. Allen E. Banik with Carlson Wade
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