Although it looks crystal clear, drinking water contains microscopic particles of a wide range of substances. Whether you receive your drinking water from a private well or a municipal water treatment system, these microscopic particles are known as total dissolved solids, or TDS. While some dissolved solids can be unpleasant – or even unhealthy – certain of these substances have benefits. To determine which dissolved solids your water contains, and in which quantities, a TDS meter can be of value. What is a TDS meter, and do you need one for your home? In this guide, we will share the details of these meters including how they work and why they can be a smart choice for homeowners concerned about water quality.
What are Total Dissolved Solids?
Total dissolved solids (TDS) are those microscopic and near-microscopic particles in water supplies. As mentioned in our introduction, dissolved solids can be unhealthy, or they can be beneficial. TDS includes:
- Minerals like calcium and magnesium
- Salts, including potassium and sodium
- Mineral bicarbonates
- Organic matter
Most of these solids originate from natural sources, such as the minerals and geological features surrounding the water source. Other sources may include agricultural runoff, storm water, and contamination or discharges from wastewater treatment facilities. Levels of TDS vary by location; in areas with higher levels, water is often described as “hard” water.
Can Water Filtration Remove Dissolved Solids?
Water filters are an effective way to remove unpleasant or even harmful substances from the water you use for drinking, cooking, and bathing. Multi-stage whole house water filter systems can and do remove suspended or dissolved solids, but in many cases, the particles are too small to be trapped by the filter elements. In fact, measuring TDS in post-filtered water can reveal that the levels are virtually unchanged from the pre-filtered water.
To ensure clean, pure water, reverse osmosis (RO) systems are designed to remove excessive levels of dissolved mineral carbonates and inorganic salts. Coupled with a water filtration system, RO units deliver fresh-tasting water to your home.
Are Total Dissolved Solids Dangerous?
Dissolved solids are found in nearly every water source. Under normal circumstances, these dissolved minerals and salts are present in very low quantities. TDS is measured two ways: parts per million (ppm) or milligrams per liter (mg/L). In general, TDS levels of 200 mg/L or lower are considered safe, while higher levels can cause serious health concerns. At levels over 400 mg/L, the water is considered unsafe to drink.
TDS imparts certain taste and odor characteristics to water. At lower levels (100-200 mg/L), these dissolved particles help the water to taste normal. In other words, the absence of these dissolved solids may make the water taste flat or unpleasant. At higher levels of TDS, the water may taste unpleasant and may have an egg-like sulfur odor. These taste and odor characteristics are tied to the pH level of the water. Below 100 mg/L of TDS, water can have a low pH, making it more acidic and influencing the taste of the water. This can damage water supply piping and water-using appliances. The higher the TDS, the higher the pH. Too high of a pH level is just as bad as too low; drinking water with high pH levels (and corresponding high TDS levels) may result in gastrointestinal issues and may irritate the skin.
Measuring Dissolved Solids: The TDS Meter
Now that you’ve learned about TDS and how it influences water quality, how can you measure it? A TDS meter is the solution. This small handheld electronic device is placed in a water sample. By pushing a button on the device, the sensor detects the TDS level and displays it on a small digital screen. TDS meters are quick and easy to check the quality of the water you drink. They can also be used to let you know when it is time to change the filter elements in your whole house water filtration system. TDS meters can also be used for measuring water quality for:
- Hydroponic systems
- Gardening and landscaping irrigation
- Swimming pools
Finally, TDS meters can help you check your whole house reverse osmosis system to ensure it is running at maximum efficiency.
While TDS meters can be a valuable addition to your home, they do not test for all contaminants like heavy metals, pesticide residues, or petroleum contamination. In addition to using a TDS meter for measuring water quality, laboratory testing of water sources can help you pinpoint the exact levels of contaminants in your water.