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  • Understanding TDS Water and Your Treatment Options

    When drinking water just doesn’t taste or look right, the culprits are often minerals and salts that have dissolved in the water. These are commonly known as total dissolved solids (TDS).

    What is TDS in water? TDS most commonly refer to the levels of dissolved ions in your water, like calcium, magnesium, potassium, sodium and nitrates. They naturally occur in water after it filters through bedrock and soil. A certain amount of dissolved solids in water is normal, and even beneficial, but problems start when levels of TDS increase beyond what would accumulate naturally.

    Fortunately, tests can reveal the amount and composition of TDS, and treatment solutions can provide safer, better-tasting water straight from the tap.

    Effects of Dissolved Solids in Water

    Unnatural levels of TDS accumulate in municipal and well water from a variety of sources, including storm water runoff, agricultural runoff, and particularly in snowy areas where salt and other minerals are used as road de-icers.

    The Environmental Protection Agency (EPA)’s National Secondary Drinking Water Regulations recommends fewer than 500 mg/L (500 ppm) of TDS in water supplies to avoid issues with taste, odor and color; however, you may also notice these problems at even lower levels. The Guidelines for Canadian Drinking Water Quality note that TDS levels above 500 mg/L result in excessive scaling in water pipes, water heaters, boilers and appliances.

    TDS can appear as discoloration in water, or you may notice these other symptoms:

    • Cloudy, turbid appearance
    • Salty, bitter or metallic taste
    • Corroded pipes or fixtures
    • Shorter lifespan for water-using appliances

    Too Much or Not Enough? How to Look For TDS in Your Water

    The EPA recommends that well owners test their water for TDS levels (and other potential issues) annually. Residents who get their water from public suppliers may also want to do a test because keeping TDS under 500 ppm is only a guideline—the agency doesn’t enforce the standard.

    To measure the amount of TDS in your water at home, you can buy a hand-held device called a TDS meter. However, it likely won’t tell you the full story. The meters often indicate how many dissolved ions are present, but they don’t tell you which ions are in there. Your water may simply have many minerals like calcium, magnesium, and potassium. On the flip side, your water also may have issues beyond TDS that you can’t see, taste or smell, such as elevated levels of contaminants like lead and arsenic.

    Since TDS water testers can’t give you an indication of the overall safety of the water, and since detecting some substances like lead requires more sophisticated assessments, consider other means of testing. A water treatment professional can take a sample and provide a much more detailed report for you, along with recommended solutions specific to any issues you may find.

    Treating TDS With Reverse Osmosis Filtration

    So can you buy a TDS water filter? Reverse osmosis (RO) water filtration systems are generally the most efficient and effective way to remove TDS, and their negative effects, from your water. Reverse osmosis drinking water systems typically contain a semipermeable membrane that separates the water from dissolved solids.

    These systems often installed at the point of use, like under the kitchen sink or hooked up to an icemaker or refrigerator’s cold-water dispenser. Typically, water first flows through a prefilter to remove larger sediment like sand and then through an activated carbon filter, which reduces chlorine taste and odor. Look for a system certified by a third party such as the Water Quality Association.

    Safety and Taste of Low TDS Water

    RO systems can reduce TDS by as much as 95% and produce water that has a TDS level of between 1 and 100 ppm. Drinking this low TDS water is safe. A study from the Water Quality Association concludes, “the consumption of low TDS water, naturally occurring or received from a treatment process, does not result in harmful effects to the human body.”

    While the RO process can remove beneficial minerals from the water, we typically get enough of these through the food we eat. Think of it this way: removing those minerals won’t likely hurt you, but keeping in the bad stuff could.

    Notably, while some people enjoy the flavor of high TDS water like bottled mineral water, our Culligan local water experts often find customers prefer the taste of water with fewer TDS. (And if you’d like to add natural calcium minerals back into reverse osmosis water, you can add Culligan’s Mineral Boost cartridge to your system.)

    With an RO system, you can essentially get the benefits of bottled water from the tap – and improve the water you use for cooking and in other beverages, like lemonade and tea. You may even find yourself staying better hydrated by turning more often to a nice glass of refreshing, great-tasting water.