Saline Water Use in the United States

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Do you wear contact lenses? If so, you most likely use a saline water solution to clean them. But what else do we use saline water for and do we really use that much? Read on to learn all about the use of saline water.

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Saline Water Use in the United States

In today's world we are all more aware of the need to conserve freshwater. With the ever-growing demand for water by growing populations worldwide, it makes sense to try to find more uses for the abundant saline water supplies that exist, mainly in the oceans. As these pie charts of the Nation's water use show, about 16 percent of all water used in the United States in 2015 was saline. (All 2015 water use information is from the report Estimated use of water in the United States in 2015.) The second chart shows that almost all saline withdrawals, over 97 percent, were used by the thermoelectric-power industry to cool electricity-generating equipment.

Fresh and saline water withdrawals and saline water withdrawals by category of use, 2015

Two pie charts, showing total water withdrawals (fresh and saline), and saline water withdrawals, for certain categories of water use, for year 2015.

 

What is saline water?

Water that is saline contains significant amounts (referred to as "concentrations") of dissolved salts, the most common being the salt we all know so well—sodium chloride (NaCl). In this case, the concentration is the amount (by weight) of salt in water, as expressed in "parts per million" (ppm). If water has a concentration of 10,000 ppm of dissolved salts, then one percent (10,000 divided by 1,000,000) of the weight of the water comes from dissolved salts.

Here are the USGS definitions for different concentration classes of saline water:

  • Fresh water - Less than 1,000 ppm
  • Slightly saline water - From 1,000 ppm to 3,000 ppm
  • Moderately saline water - From 3,000 ppm to 10,000 ppm
  • Highly saline water - From 10,000 ppm to 35,000 ppm
Saline water withdrawals by State, 2015

 

Saline water withdrawals by State, 2015

Florida had the largest saline withdrawals, accounting for approximately 23 percent of the total in the United States, mostly saline surface-water withdrawals for thermoelectric power. Oklahoma and Texas accounted for about 50 percent of the total saline groundwater withdrawals in the United States, mostly for mining.

 

Trends in saline-water withdrawals, 1950-2015

Trends in total fresh and saline water withdrawals, 1950-2015

Trends in total fresh and saline water withdrawals, 1950-2015.

As our trends chart shows, the use of saline water, and freshwater, also, has been trending downward since peaking in 1980. Of interest, from 1950 to 1975 the use of saline water increased at a much higher rate than freshwater use.

 

 

 

 

 

 

 

 

Water withdrawals for the United States, 1950-2010.  Data are in billion gallons per day (Bgal/d)

  1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Fresh 174 227 240 270 318 342 363 336 335 337 349 349 306
Saline 10 19 31 44 54 70 71.9 60.3 68.3 60.8 63.5 60.9 48.3
TOTAL 184 246 271 314 372 412 435 396 403 398 416 410 355

Data for freshwater withdrawals for 1980-2000 have been revised from original published values