Does High TDS Mean You Need a Water Filter?

If you know anything about pure water, you know it is colorless, odorless, and tasteless. But because water is an excellent solvent, it can dissolve different materials that can change its color, smell, and taste – not only the sugar in your morning brew but also a variety of organic and inorganic materials collectively called TDS (Total Dissolved Solids).

Perhaps when you saw “high TDS” in the title of this article, you immediately assumed the worst. After all, water companies often market TDS as bad for consumers, carrying on the stereotype. However, high TDS isn’t automatically dangerous. Ultimately, it depends more on the nature of the dissolved solids in the water than the amount.

But make no mistake, TDS can alter the aesthetics of your drinking water – its color, scent, and taste profile. It can also build up in pipes and appliances in higher concentrations, reducing their performance and increasing maintenance costs.

If you want to learn about TDS in drinking water, this article explains what they are, the different types, how to measure them, and what they can tell you about your water supply. It also reveals whether you need a filter if your water has a high TDS level.

What is TDS?

TDS stands for Total Dissolved Solids. It refers to the total amount of dissolved organic and inorganic matter in a volume of water. Essentially, TDS includes everything in the water besides the H2O molecules. The higher the TDS level, the more materials are dissolved in the water.

Types of TDS in Tap Water

Total dissolved solids comprise various metals, minerals, salts, anions, and cations dissolved in water. The following list details some common ones that may be present in your drinking water:

  • minerals (calcium, magnesium, potassium, fluoride)
  • metals (zinc, aluminum, iron, copper, lead, cadmium)
  • chemicals and chemical elements (pesticides, herbicides, chlorine, chloramines, nitrate, sulfates, arsenic)
  • salts (sodium, chloride)
  • microbes (bacteria, viruses, parasites)
  • bicarbonates

Sources of TDS in Drinking Water

As water journeys from the source to your tap, it often encounters various solids in the environment. As explained earlier, water is an excellent solvent, meaning it can pick up and absorb many of these solids and bring them straight to your tap.

Organic compounds can originate from rivers, mineral springs, salt deposits, seawater intrusion, carbonate deposits, and other sources. A classic example is high amounts of TDS in water from a mineral spring. Because the water in a mineral spring typically flows underground through rocks with high mineral content, it can dissolve many minerals found in the rock and soil it passes over or through – calcium, magnesium, sodium, etc. As the water dissolves these minerals, they remain at varying concentration levels. This natural process helps the water taste “right” by slightly raising its pH, but the water can also dissolve potentially harmful metallic compounds like copper, lead, zinc, and iron.

Humans also play a significant role in accumulating dissolved solids in drinking water sources. For instance, chlorine may come from water treatment plants, pesticides and herbicides may come from agricultural run-off, and lead may come from old plumbing pipes. Sometimes, dissolved solids are purposefully added to water, as bottled mineral water in the grocery store may contain mineral additives, like electrolytes and fluoride, which are not found in “pure” water.

Other man-made sources of TDS in drinking water include:

  • water treatment chemicals
  • urban and agricultural run-off
  • salts used for road de-icing
  • sewage and industrial wastewater
  • plumbing pipes and hardware
  • anti-skid materials

How To Measure TDS in Water

The simplest way to measure dissolved solids in water is to use a TDS meter (also known as a TDS tester). Since dissolved ions like salts and minerals increase the conductivity of water, a TDS meter can measure the conductivity of the solution and estimate the TDS from that reading. The higher the amount of dissolved ionized solids, the higher the water’s electrical conductivity.

Many TDS meters display readings in parts per million (ppm) — a reading of 1 ppm means that the water contains 1 milligram of dissolved solids per kilogram of water. However, conductivity tests are not always reliable.

TDS meters measure the conductivity of water and multiply the result by a conversion factor. But this only works if the dissolved solids in the water produce ions. Some solids, such as pesticides, gasoline, motor oil, and pharmaceuticals, don’t produce ions when dissolved and are undetected by TDS meters.

Sure, you can purchase a TDS meter to conduct a baseline assessment of your water. But before buying one, you should know that it does not check for the presence of contaminants in water. That means a TDS meter may indicate that your water has an excellent TDS rating, causing you to believe that your water is safe, while the water still contains all kinds of potentially dangerous pollutants.

This being the case, consider sending a water sample to a water testing center or laboratory to reveal precisely what types of TDS are in your water. Also, your water supplier must test public water supplies and maintain reports regarding water quality and will provide them upon request.

Learn more: Why TDS is Just a Myth For Measuring Drinking Water Quality

Effects of High TDS in Water

According to the EPA, the maximum concentration of TDS in drinking water is 500 ppm. However, many water supplies have TDS levels that surpass this limit. Readings above 500 ppm require further investigation for toxic particles, chemicals, and heavy metals, and readings above 1000 ppm are considered unsafe for human consumption. Again, it is essential to remember that when it comes to your health, the type of dissolved solids in your water is more important than the amount.

The following are several effects high TDS can have in water:

Weird taste and smell

A high TDS level means you have an abundance of dissolved minerals in your water, which typically includes minerals. But even if the high TDS level is due to lots of beneficial minerals, it can give water a bitter, metallic, or salty taste, discolor the water, and create an unpleasant odor.

If your water has high chlorine levels, you may find that your water has a chemical taste and smell. Also, when cooking, your pasta or other meals can absorb an unpleasant taste from the boiling water. The higher the TDS concentration, the stronger the flavor will be. (A reverse osmosis system is recommended to improve the taste and smell of bitter tap water.)

Tooth pitting and discoloration

High TDS levels in water can also cause tooth pitting or discoloration, mainly if the TDS includes high amounts of fluoride. While small amounts of fluoride may benefit teeth, too much can lead to undesirable cosmetic effects, especially in children.

Dry, itchy hair and skin

If your skin is sensitive and is repeatedly exposed to water with high mineral content (mainly calcium and magnesium), it can result in persistent dryness. You may find yourself moisturizing your skin several times a day, all to no avail. That’s because when water contains high amounts of calcium, it can change the skin’s oil chemistry, hindering its ability to produce natural oils that keep the skin supple. But even worse, this residue can disrupt your skin barrier, clog your pores, and leave your skin susceptible to acne breakouts, inflammation, eczema, pimples, rashes, itching, blemishes, and many other adverse skin conditions.

Like the skin, hard water can make it challenging to achieve a thorough rinse, causing a buildup in your hair, which can leave behind residue. It doesn’t matter if you wash your hair several times a day trying to fix the problem; nothing will change. That’s because the issue concerns what’s in your water, not your rinse, lather, or routine.

Learn more: Is Tap Water Bad for Your Hair and Skin?

Scale buildup in pipes, plumbing fixtures, and appliances

High mineral content in your water can also lead to pesky household problems, including:

  • Scale buildup in your pipes, restricting water flow and pressure (a water softener is recommended to filter calcium and magnesium and can prevent scale buildup.)
  • Damage to appliances like water heaters, shortening their lifespan and effectiveness
  • Stains and limescale deposits on countertops, shower doors, sinks, tubs, faucets, and toilets
  • Faded colors on laundry
  • Water spots on dishes and utensils

Learn more: How to Save Your Water Heater from the Damaging Effects of Hard Water

Severe health problems (and even death)

While high TDS is typically caused by lots of minerals in the water, which usually have little to no short-term effect on human health, other toxic compounds in the water, such as lead, arsenic, and nitrate, can be detrimental to our health. For example, even in small doses, lead exposure can cause brain and nervous system damage, while PFAS exposure is linked to cancer, thyroid disease, high cholesterol, and other health problems.


Is Low TDS in Water Harmful?

If your water sample contains less than 100 ppm, it is generally considered low TDS content. A low TDS typically means the water lacks minerals, such as calcium, magnesium, and zinc, leaving the water with a flat taste. If the water contains those beneficial minerals, 150-250 ppm can be an excellent range for optimal health. However, if it includes residuals from pesticides, PFAS, lead, and similar contaminants, 100 ppm would be an extremely high reading, and drinking the water would be dangerous.

Does a high TDS meter reading mean you need a water filter?

While you can use your water’s TDS level to determine if you need a water softener to prevent scale buildup due to mineral accumulation in pipes and appliances, you shouldn’t rely on it alone to decide if you need a water filter.

To decide if you need a water filter for your home, your best options are to request a detailed water quality report from your local water supplier or send a water sample from your home to a certified laboratory for testing. If there are contaminants in your water, knowing which ones are present will help you choose a water filter for your home.

TDS Treatment with Springwell

If you are concerned about your water’s TDS level, a high-quality water filter system is your best choice for clean, safe, great-tasting water. However, determining if the dissolved solids are harmful or beneficial requires research and analysis. If your water contains essential electrolytes and minerals, you don’t want to unintentionally filter them out with the unhealthy stuff.

Luckily, our Whole House Water Filter System can help eliminate toxic contaminants like copper, lead, chromium-6, pesticides, pharmaceuticals, and disinfection byproducts without removing beneficial compounds. It also removes chlorine and other contaminants that cause bad taste and odors, leaving your entire household with refreshing and great-tasting water. The sediment pre-filter blocks out dirt, sand, silt, debris, rust flakes, and other suspended solid particles 5 microns or above in size. It also reduces cloudiness in water caused by suspended solids that can cause the water to appear brown, orange, or yellow.

If you’re looking for a system that filters water at specific taps in your home, there are many under counter or countertop water filter options, offering various levels of filtration power depending on what contaminants you need to address.

Contact us for more information about TDS and water filters, and we’ll be happy to answer your questions. Also, browse our collection of whole house water filters, under-counter reverse osmosis systems, and other drinking water systems, and feel free to contact us with any questions.

Final Thoughts

High TDS in drinking water isn’t always dangerous – it ultimately depends on the types of dissolved compounds in the water. So, when testing your water for TDS, look beyond the TDS count, and pay close attention to common dissolved solids like lead, copper, pesticides, chlorine, etc. If your water contains these toxic contaminants, consider shopping our line of water filtration products, or call or visit us for more information.