Does Reverse Osmosis Remove Total Dissolved Solids From Drinking Water
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Does Reverse Osmosis Remove Total Dissolved Solids (TDS) From Water?

Welcome to our comprehensive guide on reverse osmosis and its effectiveness in removing total dissolved solids (TDS) from water.

In this article, we will delve into the concept of TDS, its impact on human health, and how reverse osmosis systems can help improve water quality. So, let’s get started!

Key Takeaways

  • Total Dissolved Solids (TDS) refers to the amount of dissolved substances in water, including minerals, salts, metals, and organic compounds.
  • TDS can be found in various water sources, including tap water, well water, and municipal water supplies.
  • Reverse osmosis (RO) is a water treatment technology that uses a semi-permeable membrane to remove impurities, including TDS.
  • RO systems are capable of reducing TDS levels in water, providing cleaner and safer drinking water.
  • When choosing an RO system, factors such as installation and maintenance, costs, water flow rate, physical space availability, and customer reviews should be considered.
  • Regular testing using a TDS meter can help monitor water quality and ensure the effectiveness of the RO system. – Alternative methods such as water distillation and water softening can also reduce or remove TDS, but RO is generally more efficient.

What Are Total Dissolved Solids?

Total Dissolved Solids (TDS) is a measure of the combined content of all organic and inorganic substances present in water, expressed in parts per million (ppm). These substances may include minerals, salts, metals, and other dissolved ions. TDS levels can vary depending on the source of water and its geographic location.

Where Are Total Dissolved Solids Found?

TDS can be found in various water sources, including tap water, well water, and municipal water supplies. The TDS levels in water can be influenced by factors such as the surrounding environment, geological formations, industrial activities, and agricultural practices. For example, water from underground sources like wells may have higher TDS levels due to mineral leaching from surrounding rocks and soil.

How Do Total Dissolved Solids Get Into A Home’s Water Supply?

Total dissolved solids (TDS) can come from various sources, both natural and man-made. Natural sources of TDS include springs, lakes, rivers, plants, and soil. For example, when water flows underground in a natural spring, it absorbs minerals, such as calcium, magnesium, and potassium, from rocks. Saltwater intrusion may contribute to the TDS concentration of groundwater in coastal areas.

Additional sources of dissolved solids include on-site sewage systems, runoff and wastewater from urban, industrial, or agricultural areas, runoff from roads treated with de-icing compounds, and wastewater from mineral extraction activities such as coal mining and natural gas drilling. Human activities can also produce TDS in water. Pesticides and herbicides may come from agricultural runoff, lead may come from old plumbing pipes, and chlorine may come from water treatment plants.

Total dissolved solids are even purposefully added to water sometimes, as bottled mineral water you come across in the grocery store may contain mineral additives.

Impact Of Total Dissolved Solids On Human Health

Total Dissolved Solids (TDS) are all the good and bad elements in drinking water, including organic and inorganic substances such as minerals, salts, metals, cations, or anions dissolved in water. The TDS level is measured in parts per million (PPM) and milligrams per liter (mg/L). The higher the TDS, the more minerals are dissolved in the water. While TDS alone is usually not a health hazard, high levels of specific ions included in the TDS measurement, such as nitrate, arsenic, aluminum, copper, or lead, could present health risks.

There are many concerns about high total dissolved solids in drinking water. Some of the biggest issues are that high total dissolved solids can lead to kidney stones, especially when hard water levels are over 500 PPM, and other health problems like heart disease and diabetes. High levels of TDS around 1000 ppm are considered unfit for human consumption, as they may taste salty, metallic, or bitter. Low levels of TDS, around 100 ppm, may have a flat or diluted taste to it and be unpalatable.

Several studies suggest that consuming water with low TDS may cause mineral leaching from healthy tissues in the body. However, the World Health Organization (WHO) states that TDS in drinking water primarily originates from natural sources, sewage, industrial waste, urban run-off, and chemicals used in the water treatment process. Inorganic minerals are considered inert because they don’t contain enzymes and therefore aren’t usable in the physiological process of human cell growth. These harmful minerals accumulate because the body cannot excrete or use them.

To ensure safe drinking water, it is recommended to test the drinking water to know the levels of TDS. If the TDS levels are high, employers should make sure that they provide their employees with safe drinking water by installing a filtration system that removes contaminants like bacteria, viruses, and heavy metals from tap or surface water.

Does Reverse Osmosis Remove Total Dissolved Solids From Water?

Does Reverse Osmosis Remove Total Dissolved Solids From Drinking Water?

Yes, reverse osmosis removes total dissolved solids (TDS) from drinking water. Reverse osmosis is the most comprehensive and popular way to remove and/or reduce TDS in water. Reverse osmosis eliminates nearly all TDS, or at least should reduce it to a very low level (< 50ppm).

RO membranes, in general, remove 90% or more of the contaminants present in the water, including TDS[2]. Reverse osmosis (RO) system reduces TDS in water by forcing the water through a semipermeable membrane.

The membrane has tiny pores that allow water molecules to pass through but block larger particles such as dissolved minerals, salts, and metals. RO removes TDS by forcing the water, under pressure, through a synthetic membrane. The membrane contains microscopic pores which will allow only molecules smaller than 0.0001 microns to pass through. As the molecules of dissolved metals and salts are large compared to the water molecules, water squeezes through the membrane leaving the metals and salts behind.

How Reverse Osmosis Systems Work

Reverse osmosis systems work by applying pressure to the water, forcing it through the semi-permeable membrane. The membrane has extremely small pores that allow water molecules to pass through while trapping larger molecules, including dissolved solids and contaminants. The purified water is then collected while the concentrated wastewater is flushed away. This process of filtration helps remove impurities, including TDS, from the water, resulting in improved water quality.

Advantages and Disadvantages Of Using Reverse Osmosis

Using a reverse osmosis system for water filtration offers several advantages. Apart from removing TDS, it also eliminates other common contaminants such as bacteria, viruses, chlorine, and heavy metals. RO systems provide a convenient and reliable source of clean drinking water, directly from the tap.

However, it is worth noting that the process of reverse osmosis can be slow and may result in some water wastage. Additionally, the membranes in RO systems require regular maintenance and replacement to ensure optimal performance.

What Else Does Reverse Osmosis Remove?

Reverse osmosis systems are effective at removing a wide range of impurities from water. In addition to TDS, RO systems can remove bacteria, viruses, chlorine, fluoride, lead, mercury, arsenic, and other contaminants. The combination of various filtration stages in RO systems ensures comprehensive purification, providing clean and safe drinking water.

Alternative Ways To Remove Total Dissolved Solids From Water

Other than RO, there are several alternative ways to remove total dissolved solids (TDS) from water, including:

1. Ion Exchange: This method lowers the TDS in water by exchanging ions with a resin bed. This method is commonly used in industrial settings and may require periodic regeneration of the resin bed to maintain its effectiveness.

2. Distillation: This method involves boiling water and then collecting the steam, which is then condensed back into water. This process removes TDS from the water.

3. Deionization: This method removes TDS by exchanging positive and negative ions with a resin bed. This method is commonly used in industrial settings and may require periodic regeneration of the resin bed to maintain its effectiveness.

4. Water Softener: This method works by removing certain minerals, such as calcium and magnesium, which can contribute to high TDS levels. However, it is important to note that water softeners may not remove all TDS from the water.

It is important to note that boiling water will not reduce TDS in water, and there is no other natural way to do it other than a water filtration system.

How To Know If Water Is Contaminated With Total Dissolved Solids

To determine the TDS levels in water, a TDS meter can be used. These handheld devices measure the electrical conductivity of water and provide an estimate of its TDS content. Higher TDS levels may indicate the presence of contaminants or excessive mineral content, requiring further water quality analysis.

How Much Total Dissolved Solids Is Safe In Well Water?

According to the United States Environmental Protection Agency (EPA), total dissolved solids (TDS) are considered a secondary standard, meaning that it is a voluntary guideline in the United States. The EPA recommends a maximum level of TDS in water of 500mg/L (500ppm). The National Secondary Drinking Water Standard for TDS in the United States is also 500 mg/L. The Bureau of Indian Standards (BIS) sets the upper limit of TDS levels in water at 500 ppm, while the World Health Organization (WHO) recommends a TDS level of 300 ppm. It is important to note that while high TDS levels may not pose a direct health risk, they can affect the taste and quality of the water, and may cause staining of fixtures and corrosion of pipes.

Key Considerations When Choosing a Total Dissolved Solids Water Filter

Installation & Maintenance

Consider the ease of installation and the maintenance requirements of the TDS water filter. Some systems may require professional installation, while others can be easily set up by homeowners. Additionally, ensure that the system’s maintenance requirements fit your lifestyle and budget.


Determine the initial cost of the TDS water filter as well as the ongoing expenses for replacement filters or membranes. Compare different options to find the most cost-effective solution for your household.

Water Flow Rate

Evaluate the water flow rate of the TDS water filter. Higher flow rates can provide more water in less time, ensuring a sufficient supply for your household’s needs.

Physical Space Available

Consider the available space for installing the TDS water filter. Some systems require more space than others, so ensure you have adequate room for the system you choose.

Customer Reviews

Read customer reviews and ratings of different TDS water filters to gauge their performance, reliability, and customer satisfaction. Real-world feedback can provide valuable insights into the effectiveness of the system.


Total dissolved solids (TDS) can affect the taste and quality of drinking water. Having high levels of TDS in water can also indicate the presence of other contaminants that may threaten human health. Reverse osmosis systems are highly effective in removing TDS from water, providing clean and safe drinking water. When selecting a reverse osmosis system, consider factors such as installation and maintenance, costs, water flow rate, available space, and customer reviews. Regular monitoring of water quality using a TDS meter is important to ensure the effectiveness of the system. While there are alternative methods to reduce TDS, reverse osmosis is generally the preferred option due to its efficiency and comprehensive filtration capabilities.

FAQs – Does RO Remove Total Dissolved Solids From Water

Q: Does reverse osmosis remove total dissolved solids (TDS)?

A: Yes, reverse osmosis (RO) is an effective method to remove total dissolved solids from water.

Q: What are TDS?

A: Total dissolved solids (TDS) refer to the combined content of inorganic and organic substances found in a liquid, primarily water.

Q: How do I measure TDS?

A: TDS can be measured using a TDS meter which detects the electrical conductivity of the water and gives a reading in parts per million (ppm) or milligrams per liter (mg/L).

Q: What is considered a high TDS level?

A: Generally, a TDS level above 500 ppm is considered high and may indicate poor water quality.

Q: Can RO membranes reduce the TDS level in water?

A: Yes, the reverse osmosis (RO) process utilizes a semi-permeable membrane to effectively reduce the TDS level in water.

Q: Does RO remove all TDS from water?

A: While reverse osmosis can significantly reduce the TDS level, it may not remove 100% of the dissolved solids. However, it can achieve a very low TDS level.

Q: Can tap water have low TDS?

A: Yes, tap water can have a low TDS level depending on the water source and treatment process it undergoes.

Q: What is the impact of high TDS in drinking water?

A: High TDS in drinking water may affect the taste, odor, and overall quality of the water. It can also pose health concerns if it contains excessive levels of certain contaminants.

Q: Can water softeners reduce TDS levels?

A: Water softeners primarily focus on removing minerals that cause hardness in water and may not have a significant impact on reducing TDS levels.

Q: Is low TDS water safe for drinking?

A: Yes, low TDS water is generally considered safe for drinking. However, it’s important to ensure that the water meets other drinking water standards and does not contain any harmful contaminants.

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