Difference Between Salt Water and Fresh Water

Our planet is covered with both huge masses of land and water everywhere. Although water comprises the maximum part of the earth, it has many forms and sources for a various organism to collect and use it.


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The oceans and seas are full of saline water; thus, glaciers and ice caps have fresh water.

Note: Fresh water is defined as having a TDS value of less than 3,000 mg/L. TDS levels between 3,000 and 10,000 mg/L are regarded as brackish water. Water that contains more than 10,000 Mg/L will be regarded as salinity. Brine is the common name for groundwater that has a salinity higher than seawater (approximately 35,000 mg/L).

Key Takeaways

  1. Saltwater has a higher salinity level than freshwater.
  2. Fish and other marine life thrive in saltwater, while freshwater is suitable for some species.
  3. Freshwater sources include lakes, rivers, and groundwater, while saltwater sources include oceans, seas, and saltwater lakes.

Salt Water vs Fresh Water

The difference between Salt Water and Fresh Water is that the saltwater is mainly present in the oceans and seas, and the salinity of the water is very high, which is unfit for human consumption while in contrast, freshwater is mainly present in the rivers, lakes, wells, streams, ponds, etc. and the salinity of the water is lower than 1% and is fit for human consumption.

Salt Water vs Fresh Water

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Salt Water is defined as the water present in the oceans and seas with a greater percentage of salt, minerals in them. Because of the high levels of salinity, it is not safe for drinking or any other purposes for humans.

Saltwater is considered to have much more density. Some examples of fishes living in saltwater are – sharks, tuna, yellowtail, bluefish, albacore, common dolphins, eels, etc.

Fresh Water is defined as water that has a composition of salt less than 1% in it and is colorless, tasteless, odorless. The freshwater sources available to humans are lakes, streams, ponds, wells, etc.

The water collected from the rain is also a source of freshwater. The freshwater is present on the earth in very little quantity and must be used efficiently. Some examples of freshwater fishes are – catfish, cisco, sunfish, etc.

Comparison Table

Parameters of ComparisonSalt WaterFresh Water
DefinitionWater with high salt and mineral content.  Water with less than 1% salt content and is without any odor, color, and taste.
Sources Sea and OceansLakes, Ponds, Streams, etc.
Density High densityLow density
Freezing Point -2 °C0 °C
Examples of Fishes Marlin, mackerel, snapper, cod, butterfish, etc.Salmon, pike, trout, catfish, charr, etc.

What is Salt Water?

Saltwater is also known as saline water this is so because of the presence of high amounts of salt present in it. Saline water is generally present in the oceans and sea.

As the earth is covered by 97% of water and the majority is of seas and oceans thus ultimately, the percentage of availability of saltwater is more.

The salinity of the saltwater is measured by different scientists, and the result of it they concluded that per liter of saltwater (seawater) contains about 35 grams of salt. It is measured in parts per thousands (ppt), thus meaning 35 ppt.

Scientists have studied properties of saline or saltwater in which one of them is about their boiling and freezing point, which is both different than freshwater.

As the main concern is related to the freezing point of the saltwater thus, it is lower than -2 C and may be lower than that. This is because of the presence of salt content in the water.

There is another property concerned with it that is the tonicity of the water, which is something related to the concept of osmosis.

The water moves through a semi-permeable membrane to the side where is a high solute concentration to make even the solution.

Therefore, saltwater is a hypertonic solution and has to be consumed frequently to absorb water and eliminate salts by the organisms living there.

salt water

What is Fresh Water?

Freshwater is defined as the water that has a low salt concentration in it along with that it does not have any taste, odor, or color. The sources of freshwater can be divided into two types – the standing reservoirs like ponds, lakes, inland wetlands, and floating reservoirs like rivers, streams, etc.

The percentage of the freshwater available on the earth is very limited and is about 3%, of which almost 1% is available to humans as the rest is preserved as ice caps and glaciers.

The organisms which cannot live in the extreme hot or extreme cold are found in freshwater. Some of the examples of fish living in freshwater are – Salmon, pike, trout, catfish, char, cisco, sunfish, etc.

The density of fresh water is about 1 g/mL, which is less than that of saltwater. Scientists have studied various properties of freshwater, and thus, tonicity is one of them.

The organism whose habitat is freshwater uses the phenomenon of osmoregulation which is, to be precise, is a process where absorbs water and frequently excrete it out from their body to even the salt concentration.

fresh water

Main Differences Between Salt Water and Fresh Water

  1. Saltwater is said to be the water with a high content of salts and minerals in it, whereas freshwater contains salts and minerals in less than 1%. 
  2. The main source of saltwater is oceans and seas, while the main source of freshwater is lakes, ponds, rivers, streams, etc. 
  3. The density of saltwater (or saline water) is quite high and measures about 1.025 gram/mL, while the density of freshwater is equal to 1 g/mL. 
  4. The freezing point of the saltwater (or saline water) is around –2 °C, while the freezing point for freshwater is about 0 °C.
  5. Examples of fishes living in saltwater are – Marlin, mackerel, snapper, albacore, shark, tuna, yellowtail, etc., while some examples of fishes living in freshwater are – catfish, cisco, sunfish, salmon, pike, char, etc. 
Difference Between Salt Water and Fresh Water
  1. https://www.sciencedirect.com/science/article/abs/pii/037702659390046A
  2. https://www.sciencedirect.com/science/article/abs/pii/S0379073819300866
  3. https://setac.onlinelibrary.wiley.com/doi/full/10.1002/etc.5620211127?casa_token=JXEsP_EhMXQAAAAA%3Abt4IrziiVMEB8CJCZfzP27kh2K2-B2rSQ930AWwVa2qB0veHGrUu1qzHEUmGsQWHJPkyRWJncSynFA
  4. https://www.sciencedirect.com/science/article/abs/pii/S0025326X01001357
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