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Home > Know Your Water > TDS of Water

TDS Of Water

What is TDS?

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). 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.

What Are Total Dissolved Solids?
"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.) 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. 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.

Where Do Dissolved Solids Come From?
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 Water?
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.

Filter Performance
Test your water to make sure the reverse osmosis or other type of water filter or water purification system has a high rejection rate and know when to change your filter (or membrane) cartridges. Know More

High TDS indicates Hard water, which causes scale buildup in pipes and valves, inhibiting performance.Know More

Coffee and Food Service
For a truly great cup of coffee, proper TDS levels must be maintained Know More

Taste & Health
“It is more important to have an adequate intake of water than it is to have enough calories. Water for drinking should be free of unpleasant odors and flavors in order to make sure the individual will ingest enough to meet his/her requirements.” - Dr. Olaf Mickelson, former president of the American Institute of Nutrition .

Why is pure water healthier to drink?
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 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 adults. 

How can water with high TDS be undesirable or harmful?
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. 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

Don’t you need the minerals in your drinking water?

Inorganic Minerals

  • It is believed that mineral waters help furnish elements for body metabolism. However, there is scientific proof to suggest that most of these minerals are in an inorganic (dead) form. While they may enter the circulation, they cannot be used in the physiological process of building the human cell.
  • With this in mind, we can see that mineral water may give "dead" or "inorganic" minerals to the body which cannot be properly assimilated.
  • These inorganic minerals only interfere with the delicate and complex biology of the body. 4
  • The body's need for minerals is largely met through foods, NOT DRINKING WATER." -The American Medical Journal
  • Fact: The organic minerals in tap water represent only 1% of the total mineral content of the water.
  • One glass of orange juice contains more beneficial minerals than thirty gallons of untreated tap water.

Organic, or Bioavailable Minerals

  • Only after they have passed through the roots of plants do these inorganic minerals become organic (through photosynthesis) and capable of being assimilated into our tissues as ORGANIC Minerals.
  • Pure water removes the inorganic mineral deposits in your body. Organic minerals are fully absorbed and remain in your tissues.
  • According to many nutritionists minerals are much easier to assimilate when they come from foods. Can you imagine going out to your garden for a cup of dirt to eat rather than a nice carrot; or drinking a whole bathtub of water for LESS calcium than that in an 8 ounce glass of milk? 
Read the Water Quality Association's Science Advisory Committee's report on "Consumption of Low TDS Water"

Water Hardness
Does hard water really create problems for the homeowner? Hard water can be a very costly addition to your home primarily because it leaves a residue called hard water scale on all washable surfaces.
Over a period of time, hard water scale can clog your plumbing which eventually reduces water pressure. It damages water heaters, dishwashers, washing machines, coffee makers and virtually all appliances through which water passes. This scale leaves spots or streaks on dishes and glassware, and dulls the look of clothing, floors, sinks, tubs, and even hair.
Corrosion often occurs because of highly acidic water that gradually eats away pipes, appliances, heaters, boilers and air-conditioning units.
Water Softeners are designed to soften water so that it washes brighter, rinses cleaner and feels much better. 
High TDS indicates Hard water, which causes scale buildup in pipes and valves, inhibiting performance. Since TDS is related to water hardness, using a TDS meter can be your first step in determining the degree of hardness of the water. Generally speaking, the higher the level of TDS (ppm), the higher the degree of hardness. 
Water hardness is typically reported in grains per gallon, milligrams per liter (mg/l) or parts per million (ppm). One grain of hardness equals approximately 17.1 ppm (mg/L) in TDS. 
Note that since TDS includes hard solids and soft solids, 17 ppm does not necessarily equal 1 grain of hardness. Coffee and Food Service

During the brewing of coffee and espresso, solids are extracted from the coffee grounds and can therefore be measured with a TDS meter. Depending on brew temperature, extraction time, grind coarseness, amount of coffee etc., the TDS value measured will vary. The monitoring of the TDS value will ensure consistent product quality and help to identify if extractions are within acceptable parameters.
You'll also want to measure incoming water TDS. For coffee brewing equipment a TDS value of 100-200 PPM is ideal. For espresso machines we recommend a TDS of approximately 50 PPM.
The above information was provided by Espresso Planet.


Water quality plays a vital role in the foodservice industry. Not only does water quality determine the taste and quality of all beverages served, it also determines the operating efficiency and longevity of water-fed foodservice equipment. As important as premium water is to a foodservice establishment's customers, so is the reduction in water related maintenance problems to the foodservice operator. Warewashers, Booster Heaters, Steamers & Combi-ovens, Proofers, Ice Machines, Coffee, Tea, & Espresso Machines, Hot Water Dispensers, etc., are all susceptible to water related problems caused by sediment, hard water (mineral scale deposits), corrosion and chlorine.
Most water supplies contain ample amounts of dissolved mineral salts such as calcium and magnesium. When water temperature increases in equipment such as booster heaters or steamers, dissolved hard minerals precipitate out of solution and reform as solid particles in the form of mineral scale deposits. These deposits “cling” to each other, building up layer upon layer of hard-to-remove mineral scale resulting in plugged nozzles, clogged pipes, and insulated heat-transfer surfaces. Scale on heating elements acts as an insulator inhibiting the heat energy transfer to the water resulting in slower heat cycles and increased energy consumption. Scale bonded to water-sensing level devices cause false probe readings, resulting in inadequate amounts of water fill. Under- filled tanks cause heating elements to dry fire and overheat, leading to costly repairs.

Minimizing the TDS of your process water can:
  • Increases Quality Uptime
  • Increases Life Cycles
  • Lowers Operating Costs
  • Lowers Maintenance Costs

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