Water containing little or no dissolved salts of calcium or magnesium, especially water containing less than 85.5 parts per million of calcium carbonate. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "soft water" in a sentence
"The only soft water available is caught in rain-barrels."