TDS in Water Explained? Effects on Taste, Safety, and Beyond

If you’re concerned about the quality of your drinking water, you may have heard the term TDS thrown around. However, TDS can also come from artificial sources like wastewater treatment plants, industrial runoff, and agricultural practices. It’s important to understand the sources of TDS in your water so you can take steps to manage and reduce it if necessary.

Key Takeaways

  • Common sources of TDS include minerals, metals, and salts naturally found in soil and rocks, as well as man-made sources like wastewater treatment plants and industrial runoff. 
  • Understanding TDS is important because it can affect your water’s taste, safety, and overall quality.

Understanding TDS

Understanding TDS is crucial for ensuring your water is safe to drink and use. Total Dissolved Solids (TDS) is a measure of all the organic and inorganic substances that are dissolved in water. TDS can include anything from minerals and salts to heavy metals and organic compounds.

What are the Substances Found in Water?

What are the Substances Found in Water

Water is a universal solvent, which means it can dissolve a wide range of substances. Some of the most common substances found in water include:

  • Inorganic Salts: These are minerals that are dissolved in water, such as calcium, magnesium, and potassium. Inorganic salts can affect the taste and hardness of water.
  • Organic Compounds: These are substances that contain carbon and are found in living organisms. Organic compounds can include everything from pesticides and herbicides to pharmaceuticals and personal care products.
  • Heavy Metals: These are high-density metals and can be toxic to humans in high concentrations. Some examples of heavy metals in water are lead, mercury, and arsenic.
  • Water Treatment Chemicals: These are chemicals that are added to water during the treatment process to disinfect and purify it. Common water treatment chemicals include chlorine, fluoride, and alum.
  • Nuisance Particles: These are substances that are not harmful to human health but can affect the appearance of water. Nuisance particles can include sediment, algae, and bacteria.

What are the Sources of TDS?

TDS can come from a variety of sources, both natural and man-made. Here are some common sources of TDS in water:

Natural Sources

  • Minerals in Soil and Rocks: Water can pick up minerals such as calcium, magnesium, and potassium as it passes through soil and rocks. These minerals dissolve in water and contribute to TDS.
  • Decaying Organic Matter: Dead plants and animals can release organic compounds into water, increasing TDS levels.
  • Saltwater Intrusion: When saltwater infiltrates freshwater aquifers, it can increase TDS levels in the affected groundwater.

Man-Made Sources

  • Agricultural Runoff: There are a variety of salts and minerals in fertilizers and pesticides used in agriculture that can contribute to TDS in nearby water sources.
  • Industrial Discharges: Many industries discharge wastewater with high TDS levels into nearby rivers and streams.
  • Water Treatment Chemicals: Some water treatment chemicals, such as chlorine and fluoride, can increase TDS levels in treated water.
  • Domestic Wastewater: Household activities such as bathing, laundry, and dishwashing can contribute to TDS levels in sewage and wastewater treatment plants.

Importance of TDS in Water

Importance of TDS in Water

Measuring TDS in water is important for several reasons. Here are some of the most important ones:

Water Quality

TDS is an important indicator of water quality. The solids in the water get dissolved easily when the TDS level is high. While some dissolved solids are harmless, others can be responsible for causing harm to human health.

Taste and Appearance

There can be an effect on the taste and appearance of water due to the presence of TDS in it. Water with a high TDS level may taste salty, bitter, or metallic. The appearance can be cloudy or hazy.

Water Treatment

TDS is an important factor in water treatment. If the TDS levels are high, it can interfere with the effectiveness of water treatment processes, like reverse osmosis or distillation.

Environmental Impact

TDS can also have an impact on the environment. High TDS levels can affect the aquatic life in rivers, lakes, and streams. It can also contribute to soil salinization and affect the growth of crops.

How Many Types of TDS are there in Water?

When it comes to checking types of TDS in water, there are two main types: natural and man-made. Natural TDS is the result of minerals and other substances that are present in the water source. Man-made TDS, on the other hand, is the result of human activity, such as using chemicals to treat water.

Depending on the source of the water, the TDS varies differently. For example, water from a mountain stream will have a different TDS than water from a lake. In general, natural TDS tends to be lower than man-made TDS.

Man-made TDS can come from various sources, including industrial activities, agricultural runoff, and municipal water treatment. In some cases, man-made TDS can be harmful to human health. For example, high lead levels in drinking water can lead to lead poisoning. Here are some examples of high and low TDS levels in water:

TDS LevelType of TDS (High or Low)
Less than 300 mg/LLow TDS. This is typical of water from mountain streams and springs.
300-600 mg/LModerate TDS. This is typical of water from rivers and lakes.
600-900 mg/LHigh TDS. This is typical of water from wells in arid regions.
Above 1200 mg/LVery high TDS.

This is typical of water from industrial sources and some municipal water supplies. It’s important to note that TDS alone is not a reliable indicator of water quality. Water having high TDS levels can indicate the presence of harmful contaminants; low TDS levels do not necessarily mean that the water is safe to drink.

Other factors, such as pH and specific pollutants, must also be considered when assessing water quality.

What are the levels of TDS?

The levels of TDS in water can vary depending on the source and location of the water. Generally, TDS levels below 500 ppm are considered safe for human consumption, while levels above 1000 ppm may cause concern. To give you an idea of the TDS levels in different types of water, we’ve created the following table:

Type of WaterTDS Level (ppm)
Bottled Water100-500 ppm
Brackish Water1000-5000 ppm
Mineral Water500-1500 ppm
Seawater35,000 ppm
Tap Water50-200 ppm

As you can see, TDS levels can vary widely depending on the type of water you’re testing. If you’re concerned about the TDS levels in your water, it’s a good idea to have it tested by a professional. They can give you a better idea of the specific TDS levels in your water and recommend a filtration system if necessary.

Measurement of TDS

TDS is typically measured in parts per million (ppm) or milligrams per liter (mg/L). There are various tools and techniques available for measuring TDS in water.

Tools and Techniques

One of the most common tools for measuring TDS in water is the TDS meter. TDS meters work by measuring the electrical conductivity of water. The more conductive the water, the higher the TDS level. TDS meters are inexpensive and easy to use, making them popular for homeowners and professionals alike.

Another technique for measuring TDS is by using a refractometer. Refractometers work by measuring the refractive index of water. The refractive index is affected by the concentration of dissolved solids in water. Refractometers are more expensive than TDS meters but can provide more accurate results.

Interpreting Results

The interpretation of TDS results depends on the use of the water. This can affect the taste, odor, and appearance of the water. TDS levels may be closely monitored in industrial applications to ensure the water quality used in production processes. In agriculture, TDS levels are used to determine the suitability of water for irrigation.

Factors Affecting TDS

Factors Affecting TDS

Water’s total dissolved solids (TDS) concentration varies depending on several factors. Here are some of the factors affecting TDS:

Water Source

The source of water is one of the primary factors affecting TDS. Groundwater sources typically have a higher TDS concentration than surface water sources. This is because groundwater comes into contact with more minerals and dissolved solids as it travels through soil and rock formations.

Treatment Chemicals

Chemicals that treat water, such as chlorine, can increase TDS concentration. This is because the chemicals themselves are dissolved solids.

Environmental Contaminants

Environmental contaminants, such as agricultural runoff and residential (urban) runoff, can contribute to TDS concentration in water. These contaminants can contain dissolved solids such as minerals and salts.


Evaporation can increase TDS concentration in water. As water evaporates, it leaves more concentrated dissolved solids behind. This is why TDS concentration is typically higher in water bodies with high evaporation rates, such as lakes in arid regions.

Water Hardness

Water hardness refers to the concentration of dissolved minerals in water. Hard water typically has a higher TDS concentration than soft water.

Industrial Discharge

Industrial discharge from factories and sewage treatment plants can contribute to TDS concentration in water. Industrial discharge can contain dissolved solids such as metals and chemicals.

Human and Animal Waste

Human and animal waste can also contribute to TDS concentration in water. This is because waste products can contain dissolved solids such as nitrogen and phosphorus.

Impact of TDS on Health

Total Dissolved Solids (TDS) in drinking water do not necessarily pose a health risk. Still, it can affect the water’s taste, appearance, and odor.


According to the World Health Organization (WHO), low to moderate levels of TDS in drinking water can benefit human health, as they provide essential minerals such as calcium, magnesium, and potassium. These minerals are vital for maintaining healthy bones, teeth, and muscles and help regulate the body’s fluid balance.


On the other hand, high levels of TDS in drinking water can cause several health problems, including:

Gastrointestinal Issues

Drinking water with high TDS levels can lead to diarrhea, vomiting, and nausea. This is because high levels of TDS can cause an imbalance in the body’s electrolytes, which can disrupt the digestive system.

Kidney Damage

High TDS levels can also strain the kidneys, which leads to kidney damage and failure. This is because the kidneys work harder to remove the excess minerals and contaminants from the body.

Cardiovascular Disease

Consuming water with high TDS levels can increase the risk of cardiovascular disease, leading to high blood pressure and an increased risk of stroke and heart attack.

Birth Defects

High TDS levels in drinking water can also lead to congenital disabilities in infants, as they can cause developmental problems in the fetus.

How to Manage and Reduce TDS?

How to Manage and Reduce TDS

If you want to manage and reduce TDS in your water, there are several methods you can use. Here are some practical solutions to help you reduce TDS levels in your water:

Reverse Osmosis

One of the most popular methods that removes total dissolved solids from water is Reverse Osmosis. This RO water purifiers remove most TDS, including dissolved salts, minerals, and dangerous chemicals, down to 0.0005 microns small.

RO systems use a semi-permeable membrane that helps to filter out contaminants from the water. The membrane allows water to pass through while blocking dissolved solids, leaving you with purified water.


Distillation is another reliable method to reduce TDS in water. It involves boiling water and then collecting the steam in a separate container and leaving behind the dissolved solids. Distillation removes up to 99% of TDS, including heavy metals and harmful impurities.

Ion Exchange

This is a process that replaces dissolved ions with other ions of similar charge. In this process, water passes through a resin bed containing charged ions. When the water passes through the resin bed, the ions are exchanged with those present in the resin bed. This process can remove hardness-causing minerals like calcium and magnesium, contributing to TDS.


It is a process that removes TDS by using a semi-permeable membrane. It is similar to reverse osmosis but operates at a lower pressure. Nanofiltration can remove up to 90% of TDS, including heavy metals, pesticides, and other contaminants.


It is a process that uses a membrane to remove particles and dissolved solids from water. The process operates at a lower pressure than reverse osmosis and removes particles to 0.01 microns. Ultrafiltration can remove up to 80% of TDS, that includes bacteria, viruses, and other contaminants.


Is 25 TDS safe for drinking water?

Yes! 25 TDS is safe for drinking water. In fact, water with low TDS levels may lack essential minerals and nutrients that are beneficial for human health. However, it is important to note that water with very high TDS levels may have an unpleasant taste and may not be suitable for consumption.

What is the appropriate TDS level for drinking water, as per WHO?

No specification is confirmed by the World Health Organization (WHO) for knowing the TDS level for drinking water. However, they recommend that the TDS level not exceed 1000 mg/L or ppm. They also state that water with TDS levels below 300 mg/L may not provide adequate levels of essential minerals.

Is 300 TDS water good for you?

Yes, 300 TDS water can be good for you. Water with TDS levels between 300 and 500 mg/L may contain essential minerals such as calcium, magnesium, and potassium that benefit human health. However, it is important to note that water with very high TDS levels may have an unpleasant taste and may not be suitable for consumption.

Does TDS indicate water quality?

TDS can indicate water quality, but it is not the only factor to consider. High TDS levels may indicate the presence of dissolved solids such as minerals, salts, and metals that can affect the taste and appearance of water.

However, low TDS levels may also indicate the absence of essential minerals beneficial for human health. Other factors to consider when evaluating water quality include pH, hardness, and the presence of contaminants such as bacteria, viruses, and chemicals.


Now that you better understand TDS in water, you can make more informed decisions about your water consumption. Remember that TDS is just one factor to consider when evaluating the quality of your drinking water.

Other factors to consider include pH, hardness, and the presence of contaminants. If you worry about the quality of your drinking water, consider having it tested by a certified laboratory.